I am a retired EE, and never paid much attention to power systems, preferring information and computation,but you make this stuff compelling! I watch your videos often, and it, almost makes me want to go back to work! Keep up the great work!
I didn't know about Dolivo-Dobrovolsky's greatest inventions until today( I never heard about him either). Thanks to you Kathy now I know who really invented the most practical and efficient 3-phase AC. Dolivo-Dobrovolsky is so under rated ! 3-Wire 3-Phase !! What a genius !
YUP, but is it a Y or Delta (meaning a triangle) which came first? Is the Y better for lighting or motors? A Delta can have a center tap in the midst of a winding to give 120 volts while a Y will give 1.732 X the voltage from phase to phase as compared to the voltage from the neutral or one side of the three windings to a phase conductor.
@@raymondgarafano8604 With the D-configuration you will have the main voltage across the windings at all times (centre tap to 120V is an abomination that offers no real advantage except an insignificant reduction of insulation needed), but you won't have a neutral point.
Simply put, this is a better explanation of these events, than I heard in my EE Engineering classes at UCLA, LOL. Kathy, I do not know your history, but you were, imho, born to teach:) Thumbs up across the board.
If a TH-cam content creator Does a better job at explaining electrical engineering, Then a professor at UCLA… Than why the heck is college so expensive???
I 100% agree. This is like 4 or 5 different lectures and probably more than 2 or 3 classEs. Power systems and electromechanics was my favorite subject and I never heard all of this together or this organized.
I worked at a power plant for 35 years and studied the basics classes back then. At the first power plant i worked at it was very old unit . The equipment worked well but has long since been removed. Glad i ran onto this channel. I certainly watch more of your videos . I remember i think that air craft were a lot higher frequency . Thanks for the history lesson..
Thanks to your presentations Kathy, as a retired electrical engineer, I am still exited about the beginnings of the sciences and their industrial implementation.
Not only do I now understand the history of this form of energy distribution, I finally have a better working understanding of the manner in which AC works in modern systems. Great job, Kathy. As a retired middle-school Natural Sciences teacher and junior college Horticultural Adjunct, it's wonderful to see someone explaining science in such a meaningful manner, using original sources. Pray, continue!
Thank you Kathy. I am so grateful for your work. There are many excellent science educators on TH-cam but your thoroughness and uninhibited passion set you apart. Your videos will play a part in my child’s education.
In all my 50 years being in electronics with a bachelor's degree in electronic engineering, I never knew the information you just presented. I'm impressed ,and decided to subscribe.
I'm glad to discover your channel! I wanted to understand 3-phase to discuss with my son who does theater lighting. This video helps make sense of electrical distribution and evolution. I liked, subscribed and plan to view more episodes. I love your enthusiasm! Thank you for the research and well organized presentation.
As a Polish electrician and electronics hacker, I'm proud of Dolivo-Dobrovolsky and absolutely delighted with this episode :) Oh, and there are a few other important Polish inventions in electrical engineering: a FW bridge rectifier (or, as Electroboom would call it, FULL BRIDGE RECTIFIER!) and an electrolytic capacitor - both invented by Karol Pollak. How would electronics look now if not for him? I guess we'd still go with the centertapped windings. To think that most of the principles and inventions lied out by him are the mainstay of modern electrical distribution systems, though now that we've got highly efficient DC/AC converters, we may be seeing some DC power system resurgence especially in the international ultra high voltage networks, not to mention the solar installations. DC switching on the other hand, arc quenching in particular... makes me wonder if it can be easily solved using IGBTs or FETs (thyristors won't do, they stay latched until power is cut off, making them useless for this purpose).
Awesome job !!!!!! I build electrical control panels for several clients including Westinghouse Nuclear (worked as an engineer for them a decade ago). Your timeline is sooooo much clearer than any I had read. I also did not know where the 50 vs 60 Hz came from ... loved that part of the story! Thanks so very much !!!!!!
Kathy, the difference you're pointing that Tesla's three phase motor needed 6 connecting wires and Dolivo´s had only 3 makes a world of difference and thanks to you I can see where these two inventors differ and the huge Dolivo-Dobrovolsky´s breakthrough. How elegant is Dolivo´s 3 wires solution; I'm in awe !. Thank you for helping me see it so clearly !
"Doliwa - is a Polish coat of arms. It was used by several szlachta families in the times of the Polish-Lithuanian Commonwealth." Dobrowolski is the family name and you can translate it as "Goodwill". But i agree that is very well made video and amazing work made by Kathy.
In fact, this is a key observation, I just saw the full episode and I was angry on so many years of misinformation. Tesla added his 3 coils variant as a variant of the 2 phases device, no study really in the background. As a filling of possibilities in the patent. He did not know the huge difference between 2 and 3 phases. In fact, all that we use today is the AEG system, so is clear for me in one moment the Americans understood but was no way for them to recognize it... Tesla himself probably knew it best.
Kathy - A very informative video. I love the history and reasons behind what we use today. I used to be a volunteer at the Folsom Historic Powerhouse in Folsom, CA. It was built in 1995 and we told our visitors that it was the first long distance 3-phase powerhouse in the US. It was built just a bit before the Niagara Fall powerhouse was put online. Niagara used Westinghouse 2-phase generators. I believe that GE got the power transmission contract to Buffalo and used Scott-Tee connected transformers to convert to 3-phase. It's interesting that the Folsom powerhouse has four 3-phase generators and used 12 wires to send the power 26 miles down to Sacramento. This was because the original governors were not stable enough to allowed the generators to be synchronized. The AC was converted to DC in Sacramento with M-G sets and then paralleled in order to power streetcars. The change to Lombard governors in around 1906 allowed the paralleling of the generators. Folsom used GE generators. I believe this was because the Livermore Brothers used financing by GE in order to build the powerhouse.
That is fascinating! I read somewhere, I think Allerhand, A “The Earliest Years of Three-Phase Power” Proceedings of the IEEE vol. 108 (Jan, 2020), that Westinghouse lost out on the Folsom gig because he refused to use 3-phase! It is fascinating to me that Westinghouse was so advanced and adventurous with AC versus DC and then so resistant to 3-phase.
@@Kathy_Loves_Physics As a Professional Control Systems Engineer, and powerhouse docent, I'm familiar with some of the older technology but never learned much of the history. Thanks for combining the two in an interesting way.
Hi Jim, Well now I'll have to visit, if still open, I'm in Citrus Heights and driven by often. Thank you for reminding me of fascinating things right near me.
My sis lives in Orangevale. The first time I was visiting years ago and biked on the bike trail along the American River I noticed the 'strange' building. Then I found the web site about Folsom Power Station. Now I recognize the face of the man who runs the site - very informative, and big thank you. I had no clue it's one of oldest hydro power houses in North America. As for the 3 phase system the one used in Europe (at least in Poland and German speaking countries) is a bit different from North American, that most of the buildings like farms, small shops, receive 3 phases 380V, in order to run 3 phase motors equipment. Most new houses are also 3 phase ready. No need for strange rotary phase converters or transformers in order to run lathe or milling machine in garage ;) - thanks to Dobrovolski and AEG. I guess two phase residential system is cheaper to build and that is main reason it remains in use until today. BTW, in Canada from time to time I see 230-240V European single phase devices run from 2 phase system: other than speed in case of motors, no real issues such as overheating.
I don't know why the TH-cam algorithm sent you my way last week, but I'm glad it did. The level of detail and citation you go into is wonderful, and you're a great story teller. Too much of what gets taught in science classes about the history of science seems to be more like folklore, so it's wonderful to find someone who digs in to get the details right.
Dobrovolsky's contribution in the development of 3-wire 3-phase electricity was really an eye opener for me as I had all along thought that Tesla was the sole inventor.I had known of the contribution of Steinmetz however.
@@europoamerico7605 from memory the first ac was generated by a French woman using a Faraday designed machine. The commutator was introduced to this machine by Andre-Marie Ampere, thus producing the first generated, rudimentary dc.
It doesn't change much whom invented what. Tech should be available to everybody,but now days Tech has become only profits and no benefits for everyone, but the end results its the same. Tech make rich some and screw over the rest,a truly excellent tech is the one that once built last over time and not break after 1 2 years due to the fact that Markets need something new every few months to make more profits... In the facts is the human kind greed that is driving today's world,along with non stop pollution of the planet. On which we all live and when the planet dies we all will die with the planet.. Capitalism and Political Corruption... 🤣🤣🤣🤣🤣🤣🤣🤣🤣
You always create exactly the right mix between illuminating personal motivations and technical background that makes following the subject not only a breeze but very enjoyable.
You should do a video about the frequency of the line. Motor users wanted lower frequencies, and lighting wanted higher frequencies. Various grids were from 16hz to 100hz over the years and finally settled on 60hz after WW2. Also there' a national time keeper to keep track of the number of 60hz transitions per day and run the grid a little faster or slower at night to "catch up" so our bedside clocks stay accurate. Lots of stuff about this that would be right up your alley!!
Very well done. People usually think I'm a weirdo when I start talking about 3 phase power...I think "most" people literally don't even know it's a thing. I used to have a big old warehouse building that was fully electric in 1910, it had modern power service but all of the original 1910 3 phase knob and tube stuff was in place and disconnected. Incredible to look at and see how advanced it was for the time. The distribution board with the slate back and live knife switches looked like something from a movie set. At over 100 years old, add some plastic insulation and change fuses for breakers and it's an almost identical system to what we are still using today. The original light switches were all rotary - this is why we say *turn* on the lights when we mean flip a switch. They have a neat little window with the word on or off when you turn it.
Kathy, I’m brand new here, but the research and delivery of information is nothing short of AMAZING! I love that you don’t waste our time with wasted B-roll videos and other stuff. Your information and expertise is why we are here. Thank you, Thank you, Thank you! (One for each phase :P)
I am so glad that I happened upon your channel. Back in the 70s, my uncle, who had been a printer since the 1920s, called me for help. He had an ancient printing press that was needed for an important production run. There was something wrong with its motor and control system - its two-phase motor and control system! This was the first I had heard about two-phase as I only knew about single-phase and three-phase. This ancient machinery looked like you would expect early 1900s devices and controls to look like. Somehow I figured out what was wrong and got it all working. That was my first and only exposure to two-phase power. Thank you so much for this terrific history lesson. You have a new subscriber!
I was surprised a number of years ago that I noticed a 2 phase motor at the scrap yard. It was for sale, but I obviously had no use for it. Two phase can be made from single phase, but I'm not an engineer to discuss this. Lancaster Pennsylvania had been wired for 2 phase many years ago, and this motor was evidently from that era.
I have never said this lightly but I love you! Your channel lit a fire in my heart over a year ago by showing me that electricity isn't as complicated as it looks on the outside while still having a close to limitless amount of uses that people would believe was just a load of fiction if they didn't see it with their own eyes. Because of you I am currently halfway through my freshman year in college majoring in electrical engineering followed by big plans based on the future uses and generation of electricity
I thought I knew this history. The Westinghouse+Tesla vs Edison story is very familiar to me. I had never heard of Dolivo-Dobrovolsky. Thanks for clearing up the details of how 3-phase became dominant electrical distribution system.
@@wiadroman Well, 50% of everything is still a lot. Is sad nowadays we are more worried who is taking more attention than who is doing more. Yes, there is a difference. Good to see at least 0.000001% of world population devotes their lives to human adavancing as civilization. Unfortunatelly that number is in decline
Kathy thanks so much for putting this up , ive been in electrical / mechanical engineering for 40 + years and you've taught me stuff i did not know ( i double checked ) , thanks for putting me right , liked and subbed , thanks again .
My life isnt quite at completion as yet. How ever Your disitation admirably executed i must say filled so many blanks. I thank you kindest Regards David
Wow! What a brilliant person and a great speaker. Looking forward to your book. I have been an electrical engineer for 45 years and didn't know the connections Kathy made with the history. How could you not love math, science, and engineering?
Great video! I'm electrical engineering student and there is a lot of talk about Michał Doliwo-Dobrowolski at my university. There is even a statue of him near the building. I wonder how many underrated scientists there are, who didn't have the political circumstances to become globally known.
Fascinating stuff, especially as I worked as a design and test engineer for a transformer manufacturing company way back in the 1970s. I couldn't do history to save my life at school, but I love the history of science and technology.
Fun fact: The 18th of December 1893 the worlds first commercial 3-phase power transfer was inaugurated. The transfer line ran between Hällsjön (the source, water turbine IIRC) and Grängesberg (at the time one of the largest iron ore mines in Europe) in southern Dalarna, Sweden. The distance of the transfer was 13 kilometers and transferred up to 9300 Volt. Remains of the facilities can be seen to this day. A testing and demonstration facility connecting Lauffen and Frankfurt in Germany had been in operation for a few years before.
8:57 Thank you, great video as always. I can remember long ago asking (pre-internet) who created this crazy star delta stuff (which is brilliant) - now I know Mikhail Dolivo-Dobrovolsky.
I'm not. As interesting as it is, it's not really something you learn in school. I do not know what you studied. But if you studied history, that's a bit too electricity-specific to be learned. If you study physics, it's more a historical thing than an electric thing. Now, if you study the history of electricity, I'm with you, you should have learned that!
I like two things about this channel. 1) The willingness to have a balanced view about history, eschewing the common practise of fixating on just the well known players (ie Tesla/Edison etc) whilst ignoring the contributions of others who were pivotal especially from a practical perspective. 2) The presenter - Kathy, you are just so damn watchable !
Wow these stories are always more complicated than one hears. Thanks for telling me about the amazing contributions of Dobrovolsky et al. There's such a lot of Tesla hype ;) Great stuff, subscribed, thanks.
Thanks for yet another exciting video! Thank you for researching so deeply into the topics you cover. I had never heard of Mikhail Dolivo-Dobrovolsky before. Way back in my youth I was an intern for two weeks at an electrical motor servicing workshop, where my first, and main, task during my internship was to re-wire a three-phase motor. This was no easy task; I remember having to remove the - very scorched and burnt - coils from the stator (a dirty, smelly job), count the number of turns in each coil , measure the wire gauge (to ensure I matched the correct electrical properties), wind the individual coils, mount them without damaging the laquering, having a 'grown-up' weld the wires together in the correct configuration, and dip-coating the stator with insulating laquer before it could be tested. I was thrilled that it ran! I had, in fact, re-wired a three-phase motor! BTW, I like that purple shirt.
Great video, Kathy! I, too, stumbled upon this video while browsing something unrelated. (Thank you Google!) Previously I had a vague understanding of the 3-wire, 3-phase system, but now I see it clearly. The history is fascinating, as well. Thank you for presenting such an interesting lesson.
Dear Kathy, Thanks so much for your amazing compilation of videos on the history of science. I understand that the amount of research that goes into making these is immense. Keep the great work going!! Glad that I came across your channel.🙏
One of my buddies in HS in 1964 and I built a 12v DC motor from nails and Cu wire for Science Fair. He went down in Vietnam January 1970 as a helicopter Army Warrant Officer. 58,479 brothers and sisters never made it back. May they rest in peace.
excellent presentation , I don't often watch yt video from beginning to end in one sitting but you know how to keep the audiences attention , thanx for clearing up some vague points of history for me Kathy , very educational !
I work on 3 phase field oriented motor control and hence pretty much into 3-ph for past 18 years or so. But have never heard of "Dobrovolsky". Thanks for the great video.
@@Kathy_Loves_PhysicsIll have to agree with mr or mrs Vapors,,, I have been an electronics engineer repair guy tinkerer and instrument maker and now in my 60s still doing work in film and i have to say your videos are really enjoyably to watch and this old dog has even leaned a few new tricks ( or at least history) of a few things even i did not know.. Thanks for taking the time and effort to do these vids and research all this wonderful history. I love your style and enthusiasm telling these stories. keep it up!
@@Kathy_Loves_Physics Nicola Tesla is not serbian. When asked by a reporter where he was from, he said Austro-Hungarian which the area is current day Croatia.
I have worked on and designed 3 phase systems for 30 years. I cant count how many books and papers I have read on the subject and this video had me rethinking a lot of what I have learned. Thanks for all the hard work researching this.
I will second that opinion. thanks Kathy! I just found your channel and will go to watch the rest of your vids. may I humbly suggest to wear a microphone I can better hear your lovely voice and content 🙂
This was an outstanding presentation, and had me riveted to the screen for the entire time, which seemed more like 3 minutes than the actual time. I had no idea that the evolution of the electric power design was so complex, with so many players.
As an engineer (retired) I've always been interested in science and technology history. Thanks for bringing to our attention some of the lessor known, but very important contributors to developing the electrical systems of our modern world.
Haven't watched this video yet as I've just discovered your channel and am slowly working my way through from the beginning. But I couldn't wait to let you know, I absolutely love both your content and style. You make it look easy but I know an awful lot of work goes into each one. Thank you so much for taking the time.
Hi Kathy, As a former electrician who worked in the electricity distribution sector and a person who has an interest in the history of science and engineering, your channel is my new TH-cam happy place. Thanks for the putting in the effort to create interesting and informative videos. No it's back to binge watching the rest of your videos. I look forward to buying and reading your books when they are published.
I am an electrician and I recently discovered your channel. As a person who considered Tesla a personal hero of mine I thank for this information. Now and forever a fan.
Wow. Really great video. I have a short attention span and get bored easily but I couldn't stop watching this story and the exciting way you told it. Thank you. I learned a lot.
Very interesting. Here I learned some things for the first time. And that comes from a guy who learned in university how to design electric motors, electric generators and electric transformers. The teachers told us in university about Mr. Dolivo-Dobrovolsky, and he was very shortly mentioned in specialty books, maybe because I graduated in Romania.
Thank you for the full history. In the US, so much is US-centric, other contributions being brushed off as inconsequential. It's good to know the full history of technological development when trying to understand the technology.
Fascinating video - Thank You!! I live in Japan near Tokyo, so we have the 100/200V 50Hz 1 ph connection to the house (the Japanese analog of the 120/240V 'Edison' connection used in the USA). This finally clears up my understanding of the 3-phase saga and of the Dobrovolsky name. I recall going through a very old electric machinery text and they mentioned the Dobrovolsky connection used in DC generators which generate 125/250 VDC with a derived neutral (the neutral is derived via a center-tapped reactor which is connected to two slip rings on the armature which are in addition to the regular commutator on the armature). This connection eliminated the need for two 125VDC machines to generate the bipolar output of -125V/0V/+125V. I've seen a couple of these types of machines. Just an interesting side note. Also, Philadelphia, PA has a 60Hz 2-phase distribution system (en.wikipedia.org/wiki/Two-phase_electric_power). I encountered an industrial machine that had one of these 2-phase motors that a friend had purchased and no one could figure out how to connect it to the local 3-phase. The contactor was a 4-pole unit as two-phase requires 4 wires. We changed out the motor as easiest solution. There used to be a book that listed the voltages, frequencies, type (AC or DC), and if the power was stable enough to run electric clocks - that was an interesting thing read. I do recall from my studies and such that Europe used to run railroads at 16.7 Hz, 41 Hz or 42 Hz was an alternate US AC frequency (there was a paper mill in Maine that ran on this), and 25 Hz (60 Hz for the signal power) was used for many years on the New Haven Railroad - the generation was 3-phase (Westinghouse turbine-alternators) and the track distribution was 1-phase. This changed over to 60 Hz commercial power in the mid 1980's with 100 Hz for the signal power. As an aside - you can clearly see the flicker of 25 Hz in incandescent bulbs - I'd notice that in some of the NYC subway stations too (they had 600V DC to 120/240 25 Hz gensets from what I could figure out). Sorry for rambling on so long... Really enjoyed this video!!!!
This (your) video presentation opened my eyes on how little I know of the other Brilliant Engineer who made our electrical world as it is today . . . Mikhail Dolivo-Dobrovolsky! I am a retired Mechanical and Electrical Engineer. Had work in Electrical Power Generating and Distribution company for 30 years. I am aware of Technical accomplishments and contributions of Edicon, Westinghouse, Steinmetz and Tesla and the involvements of financiers J.P. Morgan et al. Never too old to learn. Thank you for your wonderful educational presentation.
As an industrial electrician for over 40 years, I routinely worked with 240 volt and 480 volt 3-phase systems. The 3-phase systems were not all the same. Some were configured as "wye" and the others were configured as "delta." To top that off, in one factory in which I worked, they used a 240 volt 3-phase system with one of the "phases" (conductors) grounded. This was called a "grounded B-phase system." Most factories do not use this system. Excellent videos, Kathy!
No, the grounded B-phase system was 240 volts. The factory also had 480 volt, 3-phase systems that had the normal ungrounded conductors. Thank you.@@RecordProduction
Great video :) Just a shame that Jonas Wenström was not mentioned, since he created a 3 phase transmission system on 9,5 kV in 1893 for the Swedish mining industry. And this was the initiator for placing the small town of Ludvika in Sweden on the map as a world leading center for power transmission.
@@Kathy_Loves_Physics I absolutely agree! This is my first time here! I’m feeling very informed on a subject I happen to find very interesting, you have a very natural gift for teaching! I will be back for more!
Until I viewed this video, I thought I understood the history of Electric power but I was sooo wrong. This lady is a fountain of proper, correct information and a talented presenter. Bill D.
A little bit of Clarification at 15:29 The picture of Tessa's 3 phase six wire transmission, is a standard motor found in the market today. The wires ends are labeled U1, V1, W1; U2, V2, W2. Because of this you can make this motor a Delta or Star or other motor, At the time of installation depending how you jump the connections. Some systems change these jumpers while running but it's rare nowadays. When you see one it's a real delight, especially when you see a person see it for the first time. The picture of M. Von Dolivo is not showing that he made 3phase but that he was working on an Improvement on his Transformer, on the right half of that picture. On the left half of his picture is a 3-phase Delta Dyno that uses slip rings. Motor with slip rings are not used very often anymore but were in the early days to help adjust the resistance of a motor dynamically. This was to help produce better running torque. In the illustration he is not dynamically changing the resistance of the slip rings. But this is something he is given credit for. Vons motor is set up as a delta.
Great exposition! Personally, I believe one key advantage of the 3-phase system over all other systems is that not only is the summed current zero at all times (which a two-phase, 180 degrees system also has, or a 4-phase system), the power transmitted over the wires is also constant at all times (assuming a linear load). This means there is much less vibration in 3-phase systems compared to other systems of similar power, allowing much lighter construction. Contrast e.g. the noisy, vibrating hand-drill operating on 1 phase for a measly 700W, with the near-silent operation of a 3-phase motor. This is because the power delivered to that drill varies between 0 and almost 1000W, 50 (or 60) times per second.
@@Kathy_Loves_Physics That hand drill is not using a 3 ph motor . It is using a "brushed" 'universal motor'. No where near the same. Also the brand and the price range of the drills vary immensely. A commercial drill has a commutator with many small bars vs a 'homeowner" drill which has a few larger ones. Much rougher and less efficient. Properly designed large dc motors are quite smooth and have much more torque that ac motors. The downside is maintenance. The new ac drives are catching up but if you need 300 percent starting torque, a wound rotor dc can't be beat. I'm retired now, ex Elevator mechanic. A humorous note, as they change out the older DC drive elevator systems, the power bill just went up. As the elevator slows down the mg set rpm changes from 1725 rpm (60 cycle 3 ph incoming) to 1875 rpm. As it slows down it pumps power back into the grid and the building draws less thru the meter. As long as there is not to much idle time the parasitic losses aren't too bad. The static drives all have resistor banks with fans to dissipate the heat generated by slowing down the load. Now the new code compliant air conditioned machine rooms have to have the tonnage for the load. Lol Joe
Thanks for this eye-opening and highly informative video. I do not recall ever having heard of Mr. Dolivo-Dobrovolsky prior to watching this video. Keep up the great work!
I'd describe myself as more of an electronics than an electrical engineer (well, former as I've been retired for a while!) but I'd never heard of Mikhail Dolivo-Dobrovolsky, either. I use electric motors a lot to power my model aeroplanes and they're brushless AC motors with their speed controlled by varying the frequency of the supply which generates the rotating magnetic field. I've never come across this series of TH-cam videos before and I'm truly impressed with the way Kathy explains so clearly. She's a wonder and I'll be watching more. There's a lot of trivia on TH-cam but there's lots of really good stuff too - and it's not so hard to find. Thanks
Another great video…again! Thank you! I went to grammar school in Lauffen, from where the first 3 Phase long distance power transmission was made and I am happy that you pay so much attention to the meaningful experiment of those brave engineers to transmit huge amounts of power over more than 100km. I can say that much of the electric history is still alive. There still is a water turbine running in the place where they had run it then. There is an ‚Oskar von Miller Street‘ running down to the cement factory. The factory still exists and AEG, the firm Dobrowolski worked for, still exists, as well as Brown‘s firm, former BBC (Brown Boveri Cie), today ABB (Asea Brown Boveri). All of them managed to be enough innovative to make it into the 21st century.
@@Kathy_Loves_Physics , ASEA claimed to have the first *commercial* three-phase long distance transfer system up and running by 1893. Perhaps worth looking into how they fit into the grand scheme of things?
Just stumbled across your channel, the algorithm picked a good one for me! You do such a great job laying out the step by step defining events that lead to great breakthroughs. Loved your demonstration setting fire to alcohol by pointing to it! Keep up the good work. I'm sure you'll keep growing your channel.
I just discovered you channel. It is great. As an American, I thought I was taught the whole story of electricity. But came to realize I only knew the American version and much was deleted or skipped entirely. American versions of history tend to exclude all others. People like Dolivo Dobrovolshy are completely overlooked. Maxwell is said to have moved to America in some books I read. Untrue Thank you for filling in all the true details.
@@millomweb No, you're wrong. We give credit where, (and to whom), it's due - Xenophobic tunnel vision, (and selective recall), tends to be a largely American, (and to a lesser extent, Russian), phenomenon, (although I concede that Russian originality of thought and technical prowess puts that of Americans to shame .. you really didn't do very well with rocketry, for instance, before Von Braun launched 'Explorer' for you, (all credit to you Yanks for that, of course; good 'American' name .. 'Von Braun' ..), on top of a Redstone rocket, (essentially, his A4/V2 on steroids, just AFTER the launch of Sputnik 1). The English, (and in case you hadn't guessed, I am a 'Brit'), are usually a bit strapped for cash & are thus driven to create, (we don't usually copy), extremely elegant, simple, (cheap), and original solutions to technical problems, (for instance, using a silver mesh to safely catalyse conc.H2O2 in monopropellant rocket engines thus removing the need for a liquid catalyst & doubling the amount of H2O2 carried for the same weight.) Secondly, if, hypothetically speaking, we 'Brits' HAD been guilty of such execrable behaviour, surely the Americans would not be so weak-minded as to merely 'ape' that behaviour ? .. As your parents might have taught you .. "Would you also put your hand in the fire if someone else did it first?" .. Oh well ..
@@Mr.Swann. Having worked with someone who worked in France for a number of years, he was surprised to learn of all the nasty stuff the brits have done in the past that the brits don't generally get to hear about.
@@millomweb Ah, yes, indeed. Our gallic 'sparring partners' over the centuries have an expression for that; in English, it is .. "PERFIDEOUS ALBION", (contemporary rendition would, perhaps, read .. "SNEAKY BRITISHNESS"). We've been hurling calumnies at one another for centuries to the point where it has become almost a National Sport. We have both competed for and had 'Empires' .. (to an extent, the French still do, and tend to treat those native to their remaining 'possessions' & 'protectorates' , it must be said, rather poorly.) The relevance of that statement is that most countries who secure independence from a 'Great Power', (not many of those remain, thankfully), run away, cheering, shouting, (bellowing whatever their National Equivalent is of the Confederate 'Rebel Yell' .. which I rather like, by the way), , & firing guns into the air ! .. HOWEVER , there is an 'agreement', 'confederacy', ''trading group of nations', (indeed, rather a mix of all of these), known as the BRITISH COMMONWEALTH. Countries which USED to be part of our 'Empire', but which are now independent, have tended to ASK to be PART of this, and remain so TO THIS DAY !! .. Canada, New Zealand, Kenya, Jamaica, India, (and quite a few others .. gosh, we DID get about a bit in the past, didn't we ?), are all members, and Australia, (who have had a couple of [referenda / referendae / referendums], am unsure of the plural form for 'referendum'), to see if they wish to forget their historical ties with us, but who's population stubbornly keep voting to stay IN this Commonwealth ! To conclude, for them to not actually detest those 'rotten chaps' who USED to 'exploit' their countries, one may, perhaps, wish to conclude that we weren't actually that bad ! .. We're still not ! There is a pragmatic reason for this; England is just one of a group of four countries forming the United Kingdom; three of these countries are on one, fairly small & crowded island. We must trade to survive, (and this has always been the case). To do this we HAVE to be fair and to 'get along' with, well, everyone ! .. (would you buy a car from someone who everyone told you was a crook, or from someone with a reputation for fairness & honesty ?) Hence, finally, you may perhaps, wish to ask your acquaintance who worked in France for verified DETAILS of .. (and I quote .. ), "all the nasty stuff the brits have done in the past that the brits don't generally get to hear about." We can then discuss this further. I enjoy a good debate, and have even been known to concede that I'm absolutely wrong, and to publically apologise .. IF it can be proven to me that I am ! .. (and most 'Brits' are fair, and open to reasoned debate in this way.) Regards, 'Swanny'; (feel free to call me that, if preferred; most of my friends do.)
@@Mr.Swann. Plural referendums, referenda #OED I guess referendae would be the plural of referenda. Regarding devolution, why is it that no one discusses where borders should be ? What if Cumbria and Northumbria wanted to be Scottish ? If Cumbria wanted to be - then what about Lancashire ? What if the only place that didn't want to be Scottish was Westminster ? Och aye the noo !
This historical approach is so helpful with my technical comprehension of AC. Seeing the solutions to the eddy current problem, for example, in fits and starts is so helpful when we're just given instruction on the state of the art, which is overwhelming in its complexity, as opposed to showing us the step-by-step evolution of each significant milestone in the developments of motors and generators. Seeing how improvements were being made, and by whom, and when, helps me break down a complex final product into something more mentally manageable. At 9:38 where you discuss the three-phase neutral connection and how, when the phases are stable no current flows through them, but they can complete the circuit, was huge for me. An example where being taught on the current state of the art is just too overwhelming, but where describing an evolutionary step (in this case, an electrically neutral connection but one that completes a circuit) helps with my overall comprehension. Seriously, thunder boomed and lightning flashed outside the moment you said 'complete the circuit!' I'm totally in love with this channel and we're so fortunate you're a prolific historian. You're such an excellent teacher and so technically gifted, and able to transfer your knowledge to our minds. What an interesting method you're using to teach physics.
I'm not only amazed by the amount of information that you share but also by the work you have done to reveal the misinformation we engineers have been taught all our lives. I like your presentation style, and I like purple!! I've been playing/working with electricity since I was a little boy, I never tire of its awesomeness. Thx!
Thank you so much, for clearing up so many things. Back in the Jurassic, when I was finishing my chemistry degree, a co-worker talked me into taking some electrical engineering courses with him. The professor who taught the DC circuit analysis class believed in teaching to the slowest one in the class (as often as not, me). The professor who taught the AC circuit analysis class did not want to be teaching rookies, nor did his TA's. Only now, with this video, has much of the AC basic theory become clear. 😎
😱😱😱😱 Derp - sounds like you got robbed. University education aint free so lecturers/professors acting like they could teach however they want in a paying class is simply unacceptable.
My goodness, your work is BRILLIANT. Having done quite a lot of research myself to separate the facts from the myth regarding Tesla's achievements it is so refreshing to find objective and data based content such as yours, and so well done. It is a breath of fresh air under a sky polluted with lies and misinformation. I only wonder if it could be possible to discuss the contributions of Jonas Wenström to the 3 phase system. Thank you and congratulations.
Thank you so much. I am sorry that I did not talk about Jonas Wenstrum who really was an important early inventor of three phase except that he didn’t get the opportunities that Dolivo-Dobrovolaky got. I mostly didn’t mention him because it felt like too complicated a story already. Still, I’m sorry about that b
@@Kathy_Loves_Physics Yeah, he died in 1893, the same year as ASEA finished their first commercial 3-phase power station. He seems to have gotten the exact same idea independently, but AEG seems to have been just a little bit ahead of ASEA.
Long live Dolivo Dobrowolski, Forget Nikola Tesla. This great discovery. Even greater than all the discoveries of Nikola Tesla. Well done, dear lady, for opening our eyes.
Dear Lady, I love your videos they are about physics. I am a retired studio grip. I worked for years as a high rigger on many rock and roll shows.?My life often depended on gravity and our chain motors to overcome it. You are a great teacher!!! Dave. David M Holt, jr. Imdb
Thank you, Kathy. I'm a chemical engineer, and I find the history of science and engineering as the technology itself. I had not heard of Dovrowalsky or his contributions to 3-phase power.
Hi Karhy, I'm glad to see someone has finally created a channel around the history of physics. My name is Donald Chase, and I have worked in the electronics industry for 40+ years. I thought of doing the same thing that you are doing, but never got around to completing the work when I realized how much work it would take to put all of my knowledge into writing. I love the way that you are doing this. You kind of remind me of Carl Sagan in how you explain the subject so almost anyone can understand it.
Donald, please, reconsider. What better way than this to share your knowledge (40 years is a long time, a lot experience), and also to leave a legacy? I don't think you can reasonably not do this until you've picked just one thing, write, and then share it with us. Only then can you say no to the re. Yeah, you're right, writing about 40 years of experience is overwhelming, hundreds of videos. But just one? Surely you could do just one. There's a definite need for you to do this.
Kathy, very good job, ("dobro") on historical popular facts about electricity and basic principles on how it works. I do agree that many science giants (known and forgotten) on which sholders Nikola Tesla was "standing" to provide to hummanity the most efficient AC motor, should be noted in schools books. In Canada elementary/high schools only Edison is related to electricity in general not even Tesla. James C Maxwell is regarded as a founder of the modern field of electrical engineering and sure in high schols he should be considered as one of 3 the greatest physics scientists in addition to Newton and Einstein. Regarding Tesla, who helped you with your "eyes openning" facts agains him and being "Tesla nuts victim" to increase your You Tube chanell profit 🙂, you proved in the conclusion of this video with two papers: Nikola Tesla's 3 phase AC patent dated 1 May 1888 and Dobrowolsky's 3 phase AC patent dated 4 March 1890, that Nikola Tesla was the first and the most important 3 phase AC motor inventor and "gold winner". Thank you and keep up doing good work!
Thank you for your video. You do an amazing job of tying loose ends together. When one gets more pieces of the puzzle fitted it make it much easier to comprehend the subject.
I've been binge watching your videos the whole week. They are entertaining and the knowledge sticks, is so much easy to remember who did or discover what, when put in context. Plus your love for the subject shows at every second. So glad I found your channel
This is absolutely brilliant work thank you so much for this video! I love how well researched this was and that it highlighted a completely unsung hero of electrification that I was totally unaware of.
So amazing... Your channel so aptly demonstrates how to appreciate science and engineering and the enormous impact it has on our daily life which we accept matter of fact. You have so beautifully summarised this in your closing statement...Dolivo Dobrovolsky demonstrated the first 3 phase motor and generator..
No mention of Jonas Wennström who had a patented 3-phase motor in 1890. He also helped to create the worlds first commercial three phase transmission line in december of 1893 (Hällsjön - Grängesberg line). His inventions helped found Swedish ASEA, that later became ABB
Kathy - Our ham radio repeater group had much discussion at one time on who came up with 60 Hz and why. I believe that the original Niagara Falls frequency was 16-2/3 Hz as it worked better for universal (AC&DC) brush motors. I think that is why the Pennsylvania Railroad chose 25 Hz for their electrification as well. Maybe also because there was less attenuation in the overhead and rails. Boy! This is interesting stuff.
Jim, the German rail traction uses 16.7Hz (1/3 of 50Hz), 15kV system. Interesting what you mentioned about Niagara Falls, maybe both have something in common as per engineering reason behind the frequency (series windings motors). There are a few different rail traction systems in Europe, so many of the new locos are build to be universal thanks to silicone and asynchronous motors.
Kathy I love your videos, love how you love physics and history! There is more to be learned here than meets the eye and ear. Your passion and enthusiasm for the subject is infectious!
Wow! This is so much more awesome in the details of how it all happened than the various books about Tesla that I have read. This clears away a bunch of the marketing hype and showmanship!
Check out the Lower Pelzer hydroelectric power plant. It went online in 1894 and still in operation. First AC powered textile plant with a 3.5 mile 3300v transmission line. Three 750kw units, one 250kw and one 1100kw. The first four were designed and built by GE and specifically Steinmetz at Mechanicsville. Four units have stationary magnetic poles with rotating AC armature and three 3300v slip rings. I believe this to be the oldest continuously operating power plant in the world.
Great stuff! There’s a lot of misinformation overhyping the achievements of Nikola Tesla recently. It’s nice to see somebody examine his contributions more objectively. He was certainly a great visionary, but the fact that he has a unit in the SI system, while Maxwell does not, is absurd.
I agree. Did you ever hear a quote about Maxwells laws from Richard Feynman where he said that it was the most important thing to happen in the 1800s and the Civil War pales in comparison? It’s a good quote
gullenator1 'Some one' - NOT somebody You will find every'body' in the cemetery A BODY is a DEAD entity - {Latin} CORPUS - from which derives the word CORPORATION - which is a DEAD entity and should always be written in ALL CAPS a BODY is a DEAD entity - {Latin} CORPUS - from which derives the word CORPORATION - which is a DEAD entity and should always be written in ALL CAPS 'One' is unique 'One is alive' understand that there has never been 'one' like you before you were born and there will never be another 'one' like you after you are DEAD. You are 'one' of a kind ---- but.. Every'body' is the same. Rotten and stinking after four days -- Your third-world education system failed you - (By deliberate action) And you failed to educate yourself. Learn the subtle differences. Also learn the difference between APPLE and Apple TESLA and Tesla ON and on TOYOTA and Toyota ARMY and Army NAVY and Navy And many others that sound the same but they are NOT THE SAME The problem here is that you and the majority were programmed to be ZOMBIES - ZOMBIES have eyes but cannot see - ears and can not hear The Programming - Indoctrination and PSYOPS has been largely successful in dumbing down the population
@@sasamladenovic6120 Having an equation you came up with named after you is pretty normal and has nothing to do with having a unit named after you which is a way of honouring you. It would be like saying, yes, it's a shame there is no street named after this author but all her books are named after her. Of course, her books are her books. It doesn't explain why no one thought she deserved to have a street named after her.
Looking forward to the Steinmetz presentation, his work on hysteresis was ground breaking and the use of phaser diagrams as a teaching and understanding aid for presenting complex ac interactions.
Kathy, I stopped everything I was doing. Not only was your presentation articulate and wondrous, but the amount of research you must have done is phenomenal. I'd wondered about three phase all my life. Dad had a three phase motor out in his shop turning a fan blade to cool the place in Summer. All I can remember was that it scared my brother and me half to death--because when you hit the switch the thing went from 0 RPM to 2,000 RPM? in 1 second. The roar of the short, squat blade caused a terrific din that still makes me shudder to this day. The only thing I've seen spinning like that was the prop on a P-51D Mustang.
I've worked in industry as a maintenance technician. I've wired a lot of 3 phase equipment. Although this video helped, I still don't fully understand 3 phase.... The person who trained me did explain a bunch, with a VOM, and how a single phase motor can run off of 2 legs of 3 phase. I also know well enough to just jog newly installed equipment to make sure it is rotating in the proper dorection. If not, just switching 2 of the 3 wires, it will ne corrected. I'm still baffled by it all, and proclaim myself a mechanic more than an electrician. Even 3 wire 220V in a home is a bit of a mystery... but I just installed 220V outlets for my welders... and everything works fine. My home is in need of a pro electrician. When they show up, I will pick their brains... Great video.... and thanks.
I am a retired EE, and never paid much attention to power systems, preferring information and computation,but you make this stuff compelling! I watch your videos often, and it, almost makes me want to go back to work! Keep up the great work!
I didn't know about Dolivo-Dobrovolsky's greatest inventions until today( I never heard about him either). Thanks to you Kathy now I know who really invented the most practical and efficient 3-phase AC. Dolivo-Dobrovolsky is so under rated ! 3-Wire 3-Phase !! What a genius !
YUP, but is it a Y or Delta (meaning a triangle) which came first? Is the Y better for
lighting or motors? A Delta can have a center tap in the midst of a winding to give
120 volts while a Y will give 1.732 X the voltage from phase to phase as compared to
the voltage from the neutral or one side of the three windings to a phase conductor.
@@raymondgarafano8604 With the D-configuration you will have the main voltage across the windings at all times (centre tap to 120V is an abomination that offers no real advantage except an insignificant reduction of insulation needed), but you won't have a neutral point.
Simply put, this is a better explanation of these events, than I heard in my EE Engineering classes at UCLA, LOL. Kathy, I do not know your history, but you were, imho, born to teach:) Thumbs up across the board.
Thanks so much
If a TH-cam content creator Does a better job at explaining electrical engineering, Then a professor at UCLA… Than why the heck is college so expensive???
@@Dennisaj excellent question, the answer is something called 'tenure' :)
I 100% agree. This is like 4 or 5 different lectures and probably more than 2 or 3 classEs. Power systems and electromechanics was my favorite subject and I never heard all of this together or this organized.
Well,
There is a huge difference between teaching "History of science " and actually doing or teaching science ...huge difference.
I worked at a power plant for 35 years and studied the basics classes back then. At the first power plant i worked at it was very old unit . The equipment worked well but has long since been removed. Glad i ran onto this channel. I certainly watch more of your videos . I remember i think that air craft were a lot higher frequency . Thanks for the history lesson..
Thanks to your presentations Kathy, as a retired electrical engineer, I am still exited about the beginnings of the sciences and their industrial implementation.
Excited vs exited 😊
@@colmcillegardner2144 thank you ☺
Not only do I now understand the history of this form of energy distribution, I finally have a better working understanding of the manner in which AC works in modern systems. Great job, Kathy. As a retired middle-school Natural Sciences teacher and junior college Horticultural Adjunct, it's wonderful to see someone explaining science in such a meaningful manner, using original sources. Pray, continue!
Thank you Kathy. I am so grateful for your work. There are many excellent science educators on TH-cam but your thoroughness and uninhibited passion set you apart. Your videos will play a part in my child’s education.
In all my 50 years being in electronics with a bachelor's degree in electronic engineering, I never knew the information you just presented.
I'm impressed ,and decided to subscribe.
I'm glad to discover your channel! I wanted to understand 3-phase to discuss with my son who does theater lighting. This video helps make sense of electrical distribution and evolution. I liked, subscribed and plan to view more episodes. I love your enthusiasm! Thank you for the research and well organized presentation.
As a Polish electrician and electronics hacker, I'm proud of Dolivo-Dobrovolsky and absolutely delighted with this episode :)
Oh, and there are a few other important Polish inventions in electrical engineering: a FW bridge rectifier (or, as Electroboom would call it, FULL BRIDGE RECTIFIER!) and an electrolytic capacitor - both invented by Karol Pollak. How would electronics look now if not for him? I guess we'd still go with the centertapped windings.
To think that most of the principles and inventions lied out by him are the mainstay of modern electrical distribution systems, though now that we've got highly efficient DC/AC converters, we may be seeing some DC power system resurgence especially in the international ultra high voltage networks, not to mention the solar installations. DC switching on the other hand, arc quenching in particular... makes me wonder if it can be easily solved using IGBTs or FETs (thyristors won't do, they stay latched until power is cut off, making them useless for this purpose).
Awesome job !!!!!! I build electrical control panels for several clients including Westinghouse Nuclear (worked as an engineer for them a decade ago). Your timeline is sooooo much clearer than any I had read. I also did not know where the 50 vs 60 Hz came from ... loved that part of the story! Thanks so very much !!!!!!
Kathy, the difference you're pointing that Tesla's three phase motor needed 6 connecting wires and Dolivo´s had only 3 makes a world of difference and thanks to you I can see where these two
inventors differ and the huge Dolivo-Dobrovolsky´s breakthrough. How elegant is Dolivo´s 3 wires solution; I'm in awe !. Thank you for helping me see it so clearly !
Invention is needed in order for refinement to occur.
"Doliwa - is a Polish coat of arms. It was used by several szlachta families in the times of the Polish-Lithuanian Commonwealth."
Dobrowolski is the family name and you can translate it as "Goodwill".
But i agree that is very well made video and amazing work made by Kathy.
@@Bialy_1 O tym że system 3-fazowy to wynalazek Polaka to wiedziałem, i tą wiedzę propagowałem. Ale co to jest 'doliwa' to już nie. Dzięki.
In fact, this is a key observation, I just saw the full episode and I was angry on so many years of misinformation. Tesla added his 3 coils variant as a variant of the 2 phases device, no study really in the background. As a filling of possibilities in the patent. He did not know the huge difference between 2 and 3 phases. In fact, all that we use today is the AEG system, so is clear for me in one moment the Americans understood but was no way for them to recognize it... Tesla himself probably knew it best.
@@costiqueR Exactly. Tesla did not know the HUGE difference between 2 phases and the REAL (Dovrowolsky´s) three phase with only three wires.
Kathy - A very informative video. I love the history and reasons behind what we use today. I used to be a volunteer at the Folsom Historic Powerhouse in Folsom, CA. It was built in 1995 and we told our visitors that it was the first long distance 3-phase powerhouse in the US. It was built just a bit before the Niagara Fall powerhouse was put online. Niagara used Westinghouse 2-phase generators. I believe that GE got the power transmission contract to Buffalo and used Scott-Tee connected transformers to convert to 3-phase. It's interesting that the Folsom powerhouse has four 3-phase generators and used 12 wires to send the power 26 miles down to Sacramento. This was because the original governors were not stable enough to allowed the generators to be synchronized. The AC was converted to DC in Sacramento with M-G sets and then paralleled in order to power streetcars. The change to Lombard governors in around 1906 allowed the paralleling of the generators. Folsom used GE generators. I believe this was because the Livermore Brothers used financing by GE in order to build the powerhouse.
That is fascinating! I read somewhere, I think Allerhand, A “The Earliest Years of Three-Phase Power” Proceedings of the IEEE vol. 108 (Jan, 2020), that Westinghouse lost out on the Folsom gig because he refused to use 3-phase! It is fascinating to me that Westinghouse was so advanced and adventurous with AC versus DC and then so resistant to 3-phase.
@@Kathy_Loves_Physics As a Professional Control Systems Engineer, and powerhouse docent, I'm familiar with some of the older technology but never learned much of the history. Thanks for combining the two in an interesting way.
Hi Jim,
Well now I'll have to visit, if still open, I'm in Citrus Heights and driven by often. Thank you for reminding me of fascinating things right near me.
@@Kathy_Loves_Physics Follow the money trail where a reason might be for this (his) reluctance.
My sis lives in Orangevale. The first time I was visiting years ago and biked on the bike trail along the American River I noticed the 'strange' building. Then I found the web site about Folsom Power Station. Now I recognize the face of the man who runs the site - very informative, and big thank you. I had no clue it's one of oldest hydro power houses in North America.
As for the 3 phase system the one used in Europe (at least in Poland and German speaking countries) is a bit different from North American, that most of the buildings like farms, small shops, receive 3 phases 380V, in order to run 3 phase motors equipment. Most new houses are also 3 phase ready. No need for strange rotary phase converters or transformers in order to run lathe or milling machine in garage ;) - thanks to Dobrovolski and AEG. I guess two phase residential system is cheaper to build and that is main reason it remains in use until today. BTW, in Canada from time to time I see 230-240V European single phase devices run from 2 phase system: other than speed in case of motors, no real issues such as overheating.
I don't know why the TH-cam algorithm sent you my way last week, but I'm glad it did. The level of detail and citation you go into is wonderful, and you're a great story teller. Too much of what gets taught in science classes about the history of science seems to be more like folklore, so it's wonderful to find someone who digs in to get the details right.
She is a great teacher.
Thanks!!! If young students were tought all these stories we would have more engineers... and we need them
Dobrovolsky's contribution in the development of 3-wire 3-phase electricity was really an eye opener for me as I had all along thought that Tesla was the sole inventor.I had known of the contribution of Steinmetz however.
This is all bull. Specially coming from a woman. Tesla invented ac period
@@europoamerico7605 Nope he didn’t. It was invented years before he was born.
@@europoamerico7605 from memory the first ac was generated by a French woman using a Faraday designed machine. The commutator was introduced to this machine by Andre-Marie Ampere, thus producing the first generated, rudimentary dc.
It doesn't change much whom invented what.
Tech should be available to everybody,but now days Tech has become only profits and no benefits for everyone, but the end results its the same.
Tech make rich some and screw over the rest,a truly excellent tech is the one that once built last over time and not break after 1 2 years due to the fact that Markets need something new every few months to make more profits...
In the facts is the human kind greed that is driving today's world,along with non stop pollution of the planet.
On which we all live and when the planet dies we all will die with the planet..
Capitalism and Political Corruption...
🤣🤣🤣🤣🤣🤣🤣🤣🤣
@@europoamerico7605 This is sex discrimination!
You always create exactly the right mix between illuminating personal motivations and technical background that makes following the subject not only a breeze but very enjoyable.
I really like listening to someone who is so comfortably versed explain a topic. Thank you.
You should do a video about the frequency of the line. Motor users wanted lower frequencies, and lighting wanted higher frequencies. Various grids were from 16hz to 100hz over the years and finally settled on 60hz after WW2. Also there' a national time keeper to keep track of the number of 60hz transitions per day and run the grid a little faster or slower at night to "catch up" so our bedside clocks stay accurate. Lots of stuff about this that would be right up your alley!!
Very well done. People usually think I'm a weirdo when I start talking about 3 phase power...I think "most" people literally don't even know it's a thing. I used to have a big old warehouse building that was fully electric in 1910, it had modern power service but all of the original 1910 3 phase knob and tube stuff was in place and disconnected. Incredible to look at and see how advanced it was for the time. The distribution board with the slate back and live knife switches looked like something from a movie set. At over 100 years old, add some plastic insulation and change fuses for breakers and it's an almost identical system to what we are still using today.
The original light switches were all rotary - this is why we say *turn* on the lights when we mean flip a switch. They have a neat little window with the word on or off when you turn it.
Kathy, I’m brand new here, but the research and delivery of information is nothing short of AMAZING! I love that you don’t waste our time with wasted B-roll videos and other stuff. Your information and expertise is why we are here.
Thank you, Thank you, Thank you!
(One for each phase :P)
You’re welcome you’re welcome you’re welcome… and thank you for the nice comment
I am so glad that I happened upon your channel. Back in the 70s, my uncle, who had been a printer since the 1920s, called me for help. He had an ancient printing press that was needed for an important production run. There was something wrong with its motor and control system - its two-phase motor and control system! This was the first I had heard about two-phase as I only knew about single-phase and three-phase. This ancient machinery looked like you would expect early 1900s devices and controls to look like. Somehow I figured out what was wrong and got it all working. That was my first and only exposure to two-phase power. Thank you so much for this terrific history lesson. You have a new subscriber!
You can create the second phase - which has a 90 degree phase shift - with a capacitor.
I was surprised a number of years ago that I noticed a 2 phase motor at the scrap yard. It was for sale, but I obviously had no use for it.
Two phase can be made from single phase, but I'm not an engineer to discuss this. Lancaster Pennsylvania had been wired for 2 phase many years ago, and this motor was evidently from that era.
@@Farm_fab interesting
. So there's a scrap yard where one can browse in Lancaster? I'm in nearby Palmyra, could tell me where this is? Thankee
7
I have never said this lightly but I love you! Your channel lit a fire in my heart over a year ago by showing me that electricity isn't as complicated as it looks on the outside while still having a close to limitless amount of uses that people would believe was just a load of fiction if they didn't see it with their own eyes. Because of you I am currently halfway through my freshman year in college majoring in electrical engineering followed by big plans based on the future uses and generation of electricity
That makes me so happy. I’m sure you are going to do amazing things and I am honored to be a part of your story.
Cheers,
Kathy
I thought I knew this history. The Westinghouse+Tesla vs Edison story is very familiar to me. I had never heard of Dolivo-Dobrovolsky. Thanks for clearing up the details of how 3-phase became dominant electrical distribution system.
X2. I thought Tesla was the only one and the creator of virtually everything
Same! Feels like his innovation was more impactful than either of edisons or teslas.. and impressive that it has stood the test of time as well!
There was no Tesla V Edison
@@kevinmithnick9993 Well, you were wrong. Tesla invented only 50% of everything, the other 50% was invented by Da Vinci.
@@wiadroman Well, 50% of everything is still a lot. Is sad nowadays we are more worried who is taking more attention than who is doing more. Yes, there is a difference. Good to see at least 0.000001% of world population devotes their lives to human adavancing as civilization. Unfortunatelly that number is in decline
Kathy thanks so much for putting this up , ive been in electrical / mechanical engineering for 40 + years and you've taught me stuff i did not know ( i double checked ) , thanks for putting me right , liked and subbed , thanks again .
Mikhail Dolivo-Dobrovolsky. Wow.
Kathy is an absolute gem. Kathy, thank you so much for sharing your wonderful knowledge.
My life isnt
quite at completion as yet. How ever Your disitation admirably executed i must say
filled so many blanks.
I thank you kindest Regards David
Wow! What a brilliant person and a great speaker. Looking forward to your book. I have been an electrical engineer for 45 years and didn't know the connections Kathy made with the history. How could you not love math, science, and engineering?
Great video! I'm electrical engineering student and there is a lot of talk about Michał Doliwo-Dobrowolski at my university. There is even a statue of him near the building. I wonder how many underrated scientists there are, who didn't have the political circumstances to become globally known.
Fascinating stuff, especially as I worked as a design and test engineer for a transformer manufacturing company way back in the 1970s.
I couldn't do history to save my life at school, but I love the history of science and technology.
Excellent talk; you have me hooked. I'm a 1965 EE graduate followed by an MS in Geophysics. It is great to be back in school.
Fun fact:
The 18th of December 1893 the worlds first commercial 3-phase power transfer was inaugurated. The transfer line ran between Hällsjön (the source, water turbine IIRC) and Grängesberg (at the time one of the largest iron ore mines in Europe) in southern Dalarna, Sweden. The distance of the transfer was 13 kilometers and transferred up to 9300 Volt. Remains of the facilities can be seen to this day.
A testing and demonstration facility connecting Lauffen and Frankfurt in Germany had been in operation for a few years before.
Jonas Wenström is sadly unknown outside Sweden.
8:57 Thank you, great video as always. I can remember long ago asking (pre-internet) who created this crazy star delta stuff (which is brilliant) - now I know Mikhail Dolivo-Dobrovolsky.
It really is amazing isn’t it?
I'm surprised I wasn't taught this in grade school, but I learn it 50 years later from this wonderful lady who loves physics & history.
I'm not. As interesting as it is, it's not really something you learn in school. I do not know what you studied. But if you studied history, that's a bit too electricity-specific to be learned. If you study physics, it's more a historical thing than an electric thing.
Now, if you study the history of electricity, I'm with you, you should have learned that!
I like two things about this channel.
1) The willingness to have a balanced view about history,
eschewing the common practise of fixating on just
the well known players (ie Tesla/Edison etc) whilst
ignoring the contributions of others who were pivotal
especially from a practical perspective.
2) The presenter - Kathy, you are just so damn watchable !
Don Unruh
Amen to that!!!
Wow these stories are always more complicated than one hears. Thanks for telling me about the amazing contributions of Dobrovolsky et al. There's such a lot of Tesla hype ;) Great stuff, subscribed, thanks.
Thanks for yet another exciting video! Thank you for researching so deeply into the topics you cover. I had never heard of Mikhail Dolivo-Dobrovolsky before. Way back in my youth I was an intern for two weeks at an electrical motor servicing workshop, where my first, and main, task during my internship was to re-wire a three-phase motor. This was no easy task; I remember having to remove the - very scorched and burnt - coils from the stator (a dirty, smelly job), count the number of turns in each coil , measure the wire gauge (to ensure I matched the correct electrical properties), wind the individual coils, mount them without damaging the laquering, having a 'grown-up' weld the wires together in the correct configuration, and dip-coating the stator with insulating laquer before it could be tested. I was thrilled that it ran! I had, in fact, re-wired a three-phase motor!
BTW, I like that purple shirt.
Great video, Kathy! I, too, stumbled upon this video while browsing something unrelated. (Thank you Google!) Previously I had a vague understanding of the 3-wire, 3-phase system, but now I see it clearly. The history is fascinating, as well. Thank you for presenting such an interesting lesson.
Dear Kathy, Thanks so much for your amazing compilation of videos on the history of science. I understand that the amount of research that goes into making these is immense. Keep the great work going!! Glad that I came across your channel.🙏
Thank you so much for your kind words.
One of my buddies in HS in 1964 and I built a 12v DC motor from nails and Cu wire for Science Fair. He went down in Vietnam January 1970 as a helicopter Army Warrant Officer. 58,479 brothers and sisters never made it back. May they rest in peace.
Your contribution and work to link history to science certainly make us well informed. Thank you for making these videos.
Purple's my favorite color! However, I found a new channel I enjoy as well, thanks for the hard work, great channel.
excellent presentation , I don't often watch yt video from beginning to end in one sitting but you know how to keep the audiences attention ,
thanx for clearing up some vague points of history for me Kathy , very educational !
Glad you liked it.
I work on 3 phase field oriented motor control and hence pretty much into 3-ph for past 18 years or so. But have never heard of "Dobrovolsky".
Thanks for the great video.
Hey Debraj, nice to see you around. I subscribe to your comment.
This is the best video per minute of time I've seen on the history of this subject by far - good job and thank you.
Thank you for the lovely comment. Made my day. 😊
@@Kathy_Loves_PhysicsIll have to agree with mr or mrs Vapors,,, I have been an electronics engineer repair guy tinkerer and instrument maker and now in my 60s still doing work in film and i have to say your videos are really enjoyably to watch and this old dog has even leaned a few new tricks ( or at least history) of a few things even i did not know.. Thanks for taking the time and effort to do these vids and research all this wonderful history. I love your style and enthusiasm telling these stories. keep it up!
@@Kathy_Loves_Physics Nicola Tesla is not serbian. When asked by a reporter where he was from, he said Austro-Hungarian which the area is current day Croatia.
I have worked on and designed 3 phase systems for 30 years. I cant count how many books and papers I have read on the subject and this video had me rethinking a lot of what I have learned. Thanks for all the hard work researching this.
I will second that opinion. thanks Kathy! I just found your channel and will go to watch the rest of your vids. may I humbly suggest to wear a microphone I can better hear your lovely voice and content 🙂
This was an outstanding presentation, and had me riveted to the screen for the entire time, which seemed more like 3 minutes than the actual time. I had no idea that the evolution of the electric power design was so complex, with so many players.
Thanks
As an engineer (retired) I've always been interested in science and technology history. Thanks for bringing to our attention some of the lessor known, but very important contributors to developing the electrical systems of our modern world.
Glad you liked it.
Love Kathy's enthusiasm. Didn't think I would watch a video on this subject to the end but she carried me to it. Well done.
I'm an electrician studying service engineering that I just found your channel and wanted to say thank you for your amazing informative content!
Haven't watched this video yet as I've just discovered your channel and am slowly working my way through from the beginning. But I couldn't wait to let you know, I absolutely love both your content and style. You make it look easy but I know an awful lot of work goes into each one. Thank you so much for taking the time.
Hi Kathy, As a former electrician who worked in the electricity distribution sector and a person who has an interest in the history of science and engineering, your channel is my new TH-cam happy place.
Thanks for the putting in the effort to create interesting and informative videos. No it's back to binge watching the rest of your videos.
I look forward to buying and reading your books when they are published.
Great video! I am an EE and took a power systems course as an undergraduate, but I never appreciated this history. Thank you so much!
I am an electrician and I recently discovered your channel. As a person who considered Tesla a personal hero of mine I thank for this information. Now and forever a fan.
Anybody notice how all of these geniuses are almost always immigrants? That's what keeps America young, vibrant and great.
Well, yeah! All of us were then.
Speak for yourself! I’m no immigrant, nor am I a genius! 😂
Yeah, but any racist xenophobe knows we’ve had the perfect amount of immigrants. The BEST immigrants, too.
Yeah, but any racist xenophobe knows we’ve had the perfect amount of immigrants. The BEST immigrants, too.
Yeah, but any racist xenophobe knows we’ve had the perfect amount of immigrants. The BEST immigrants, too.
Wow. Really great video. I have a short attention span and get bored easily but I couldn't stop watching this story and the exciting way you told it. Thank you. I learned a lot.
Very interesting. Here I learned some things for the first time.
And that comes from a guy who learned in university how to design electric motors, electric generators and electric transformers.
The teachers told us in university about Mr. Dolivo-Dobrovolsky, and he was very shortly mentioned in specialty books, maybe because I graduated in Romania.
Thank you for the full history. In the US, so much is US-centric, other contributions being brushed off as inconsequential. It's good to know the full history of technological development when trying to understand the technology.
Really interesting and explained so well!! All of those guys were geniuses - where would we be without them? 🤔
Thanks Kathy...great reserch..loved every minute
Fascinating video - Thank You!! I live in Japan near Tokyo, so we have the 100/200V 50Hz 1 ph connection to the house (the Japanese analog of the 120/240V 'Edison' connection used in the USA).
This finally clears up my understanding of the 3-phase saga and of the Dobrovolsky name. I recall going through a very old electric machinery text and they mentioned the Dobrovolsky connection used in DC generators which generate 125/250 VDC with a derived neutral (the neutral is derived via a center-tapped reactor which is connected to two slip rings on the armature which are in addition to the regular commutator on the armature). This connection eliminated the need for two 125VDC machines to generate the bipolar output of -125V/0V/+125V. I've seen a couple of these types of machines. Just an interesting side note.
Also, Philadelphia, PA has a 60Hz 2-phase distribution system (en.wikipedia.org/wiki/Two-phase_electric_power). I encountered an industrial machine that had one of these 2-phase motors that a friend had purchased and no one could figure out how to connect it to the local 3-phase. The contactor was a 4-pole unit as two-phase requires 4 wires. We changed out the motor as easiest solution.
There used to be a book that listed the voltages, frequencies, type (AC or DC), and if the power was stable enough to run electric clocks - that was an interesting thing read. I do recall from my studies and such that Europe used to run railroads at 16.7 Hz, 41 Hz or 42 Hz was an alternate US AC frequency (there was a paper mill in Maine that ran on this), and 25 Hz (60 Hz for the signal power) was used for many years on the New Haven Railroad - the generation was 3-phase (Westinghouse turbine-alternators) and the track distribution was 1-phase. This changed over to 60 Hz commercial power in the mid 1980's with 100 Hz for the signal power.
As an aside - you can clearly see the flicker of 25 Hz in incandescent bulbs - I'd notice that in some of the NYC subway stations too (they had 600V DC to 120/240 25 Hz gensets from what I could figure out).
Sorry for rambling on so long...
Really enjoyed this video!!!!
This (your) video presentation opened my eyes on how little I know of the other Brilliant Engineer who made our electrical world as it is today . . . Mikhail Dolivo-Dobrovolsky!
I am a retired Mechanical and Electrical Engineer. Had work in Electrical Power Generating and Distribution company for 30 years. I am aware of Technical accomplishments and contributions of Edicon, Westinghouse, Steinmetz and Tesla and the involvements of financiers J.P. Morgan et al.
Never too old to learn. Thank you for your wonderful educational presentation.
As an industrial electrician for over 40 years, I routinely worked with 240 volt and 480 volt 3-phase systems. The 3-phase systems were not all the same. Some were configured as "wye" and the others were configured as "delta." To top that off, in one factory in which I worked, they used a 240 volt 3-phase system with one of the "phases" (conductors) grounded. This was called a "grounded B-phase system." Most factories do not use this system.
Excellent videos, Kathy!
480v ?
@@RecordProduction American 3 phase system
No, the grounded B-phase system was 240 volts. The factory also had 480 volt, 3-phase systems that had the normal ungrounded conductors. Thank you.@@RecordProduction
Yes, 480 volts. Some of their 480-volt, 3-phase systems were 480 volt / 277 volt, wye connected systems.@@RecordProduction
Great video :) Just a shame that Jonas Wenström was not mentioned, since he created a 3 phase transmission system on 9,5 kV in 1893 for the Swedish mining industry. And this was the initiator for placing the small town of Ludvika in Sweden on the map as a world leading center for power transmission.
You're a great editor. Thank you Kathy for all your hard work and diligence! What an informative video. Keep it up!!
Thanks 😊
@@Kathy_Loves_Physics I absolutely agree! This is my first time here! I’m feeling very informed on a subject I happen to find very interesting, you have a very natural gift for teaching! I will be back for more!
Until I viewed this video, I thought I understood the history of Electric power but I was sooo wrong.
This lady is a fountain of proper, correct information and a talented presenter.
Bill D.
Kathy, You bring truth and justice, full and concise, magnificently, in the name of history and science combined.
A little bit of Clarification at 15:29
The picture of Tessa's 3 phase six wire transmission, is a standard motor found in the market today. The wires ends are labeled U1, V1, W1; U2, V2, W2. Because of this you can make this motor a Delta or Star or other motor, At the time of installation depending how you jump the connections. Some systems change these jumpers while running but it's rare nowadays. When you see one it's a real delight, especially when you see a person see it for the first time.
The picture of M. Von Dolivo is not showing that he made 3phase but that he was working on an Improvement on his Transformer, on the right half of that picture. On the left half of his picture is a 3-phase Delta Dyno that uses slip rings. Motor with slip rings are not used very often anymore but were in the early days to help adjust the resistance of a motor dynamically. This was to help produce better running torque. In the illustration he is not dynamically changing the resistance of the slip rings. But this is something he is given credit for. Vons motor is set up as a delta.
As a Tesla fan for a lot of years, this was a real eye opener. Great research, great deliver and graphics. Beers on me.
Great exposition!
Personally, I believe one key advantage of the 3-phase system over all other systems is that not only is the summed current zero at all times (which a two-phase, 180 degrees system also has, or a 4-phase system), the power transmitted over the wires is also constant at all times (assuming a linear load). This means there is much less vibration in 3-phase systems compared to other systems of similar power, allowing much lighter construction.
Contrast e.g. the noisy, vibrating hand-drill operating on 1 phase for a measly 700W, with the near-silent operation of a 3-phase motor. This is because the power delivered to that drill varies between 0 and almost 1000W, 50 (or 60) times per second.
Good point
@@Kathy_Loves_Physics That hand drill is not using a 3 ph motor . It is using a "brushed" 'universal motor'. No where near the same. Also the brand and the price range of the drills vary immensely. A commercial drill has a commutator with many small bars vs a 'homeowner" drill which has a few larger ones. Much rougher and less efficient. Properly designed large dc motors are quite smooth and have much more torque that ac motors. The downside is maintenance. The new ac drives are catching up but if you need 300 percent starting torque, a wound rotor dc can't be beat. I'm retired now, ex Elevator mechanic. A humorous note, as they change out the older DC drive elevator systems, the power bill just went up. As the elevator slows down the mg set rpm changes from 1725 rpm (60 cycle 3 ph incoming) to 1875 rpm. As it slows down it pumps power back into the grid and the building draws less thru the meter. As long as there is not to much idle time the parasitic losses aren't too bad. The static drives all have resistor banks with fans to dissipate the heat generated by slowing down the load. Now the new code compliant air conditioned machine rooms have to have the tonnage for the load. Lol Joe
Thanks for this eye-opening and highly informative video. I do not recall ever having heard of Mr. Dolivo-Dobrovolsky prior to watching this video. Keep up the great work!
I'd describe myself as more of an electronics than an electrical engineer (well, former as I've been retired for a while!) but I'd never heard of Mikhail Dolivo-Dobrovolsky, either. I use electric motors a lot to power my model aeroplanes and they're brushless AC motors with their speed controlled by varying the frequency of the supply which generates the rotating magnetic field.
I've never come across this series of TH-cam videos before and I'm truly impressed with the way Kathy explains so clearly. She's a wonder and I'll be watching more. There's a lot of trivia on TH-cam but there's lots of really good stuff too - and it's not so hard to find. Thanks
So glad you liked it
Another great video…again! Thank you! I went to grammar school in Lauffen, from where the first 3 Phase long distance power transmission was made and I am happy that you pay so much attention to the meaningful experiment of those brave engineers to transmit huge amounts of power over more than 100km. I can say that much of the electric history is still alive. There still is a water turbine running in the place where they had run it then. There is an ‚Oskar von Miller Street‘ running down to the cement factory. The factory still exists and AEG, the firm Dobrowolski worked for, still exists, as well as Brown‘s firm, former BBC (Brown Boveri Cie), today ABB (Asea Brown Boveri). All of them managed to be enough innovative to make it into the 21st century.
Wow that is so cool.
@@Kathy_Loves_Physics , ASEA claimed to have the first *commercial* three-phase long distance transfer system up and running by 1893. Perhaps worth looking into how they fit into the grand scheme of things?
Just stumbled across your channel, the algorithm picked a good one for me! You do such a great job laying out the step by step defining events that lead to great breakthroughs. Loved your demonstration setting fire to alcohol by pointing to it! Keep up the good work. I'm sure you'll keep growing your channel.
I just discovered you channel. It is great.
As an American, I thought I was taught the whole story of electricity. But came to realize I only knew the American version and much was deleted or skipped entirely. American versions of history tend to exclude all others. People like Dolivo Dobrovolshy are completely overlooked. Maxwell is said to have moved to America in some books I read. Untrue Thank you for filling in all the true details.
The English do that too. Americans only copied the idea from the English ;)
@@millomweb No, you're wrong. We give credit where, (and to whom), it's due - Xenophobic tunnel vision, (and selective recall), tends to be a largely American, (and to a lesser extent, Russian), phenomenon, (although I concede that Russian originality of thought and technical prowess puts that of Americans to shame .. you really didn't do very well with rocketry, for instance, before Von Braun launched 'Explorer' for you, (all credit to you Yanks for that, of course; good 'American' name .. 'Von Braun' ..), on top of a Redstone rocket, (essentially, his A4/V2 on steroids, just AFTER the launch of Sputnik 1). The English, (and in case you hadn't guessed, I am a 'Brit'), are usually a bit strapped for cash & are thus driven to create, (we don't usually copy), extremely elegant, simple, (cheap), and original solutions to technical problems, (for instance, using a silver mesh to safely catalyse conc.H2O2 in monopropellant rocket engines thus removing the need for a liquid catalyst & doubling the amount of H2O2 carried for the same weight.) Secondly, if, hypothetically speaking, we 'Brits' HAD been guilty of such execrable behaviour, surely the Americans would not be so weak-minded as to merely 'ape' that behaviour ? .. As your parents might have taught you .. "Would you also put your hand in the fire if someone else did it first?" .. Oh well ..
@@Mr.Swann. Having worked with someone who worked in France for a number of years, he was surprised to learn of all the nasty stuff the brits have done in the past that the brits don't generally get to hear about.
@@millomweb Ah, yes, indeed. Our gallic 'sparring partners' over the centuries have an expression for that; in English, it is .. "PERFIDEOUS ALBION", (contemporary rendition would, perhaps, read .. "SNEAKY BRITISHNESS"). We've been hurling calumnies at one another for centuries to the point where it has become almost a National Sport. We have both competed for and had 'Empires' .. (to an extent, the French still do, and tend to treat those native to their remaining 'possessions' & 'protectorates' , it must be said, rather poorly.) The relevance of that statement is that most countries who secure independence from a 'Great Power', (not many of those remain, thankfully), run away, cheering, shouting, (bellowing whatever their National Equivalent is of the Confederate 'Rebel Yell' .. which I rather like, by the way), , & firing guns into the air ! .. HOWEVER , there is an 'agreement', 'confederacy', ''trading group of nations', (indeed, rather a mix of all of these), known as the BRITISH COMMONWEALTH. Countries which USED to be part of our 'Empire', but which are now independent, have tended to ASK to be PART of this, and remain so TO THIS DAY !! .. Canada, New Zealand, Kenya, Jamaica, India, (and quite a few others .. gosh, we DID get about a bit in the past, didn't we ?), are all members, and Australia, (who have had a couple of [referenda / referendae / referendums], am unsure of the plural form for 'referendum'), to see if they wish to forget their historical ties with us, but who's population stubbornly keep voting to stay IN this Commonwealth ! To conclude, for them to not actually detest those 'rotten chaps' who USED to 'exploit' their countries, one may, perhaps, wish to conclude that we weren't actually that bad ! .. We're still not ! There is a pragmatic reason for this; England is just one of a group of four countries forming the United Kingdom; three of these countries are on one, fairly small & crowded island. We must trade to survive, (and this has always been the case). To do this we HAVE to be fair and to 'get along' with, well, everyone ! .. (would you buy a car from someone who everyone told you was a crook, or from someone with a reputation for fairness & honesty ?) Hence, finally, you may perhaps, wish to ask your acquaintance who worked in France for verified DETAILS of .. (and I quote .. ), "all the nasty stuff the brits have done in the past that the brits don't generally get to hear about." We can then discuss this further. I enjoy a good debate, and have even been known to concede that I'm absolutely wrong, and to publically apologise .. IF it can be proven to me that I am ! .. (and most 'Brits' are fair, and open to reasoned debate in this way.) Regards, 'Swanny'; (feel free to call me that, if preferred; most of my friends do.)
@@Mr.Swann. Plural referendums, referenda #OED
I guess referendae would be the plural of referenda.
Regarding devolution, why is it that no one discusses where borders should be ? What if Cumbria and Northumbria wanted to be Scottish ? If Cumbria wanted to be - then what about Lancashire ?
What if the only place that didn't want to be Scottish was Westminster ?
Och aye the noo !
This historical approach is so helpful with my technical comprehension of AC. Seeing the solutions to the eddy current problem, for example, in fits and starts is so helpful when we're just given instruction on the state of the art, which is overwhelming in its complexity, as opposed to showing us the step-by-step evolution of each significant milestone in the developments of motors and generators. Seeing how improvements were being made, and by whom, and when, helps me break down a complex final product into something more mentally manageable.
At 9:38 where you discuss the three-phase neutral connection and how, when the phases are stable no current flows through them, but they can complete the circuit, was huge for me. An example where being taught on the current state of the art is just too overwhelming, but where describing an evolutionary step (in this case, an electrically neutral connection but one that completes a circuit) helps with my overall comprehension. Seriously, thunder boomed and lightning flashed outside the moment you said 'complete the circuit!'
I'm totally in love with this channel and we're so fortunate you're a prolific historian. You're such an excellent teacher and so technically gifted, and able to transfer your knowledge to our minds. What an interesting method you're using to teach physics.
I'm not only amazed by the amount of information that you share but also by the work you have done to reveal the misinformation we engineers have been taught all our lives. I like your presentation style, and I like purple!! I've been playing/working with electricity since I was a little boy, I never tire of its awesomeness. Thx!
Thank you so much, for clearing up so many things. Back in the Jurassic, when I was finishing my chemistry degree, a co-worker talked me into taking some electrical engineering courses with him. The professor who taught the DC circuit analysis class believed in teaching to the slowest one in the class (as often as not, me). The professor who taught the AC circuit analysis class did not want to be teaching rookies, nor did his TA's. Only now, with this video, has much of the AC basic theory become clear. 😎
😱😱😱😱
Derp - sounds like you got robbed.
University education aint free so lecturers/professors acting like they could teach however they want in a paying class is simply unacceptable.
My goodness, your work is BRILLIANT. Having done quite a lot of research myself to separate the facts from the myth regarding Tesla's achievements it is so refreshing to find objective and data based content such as yours, and so well done. It is a breath of fresh air under a sky polluted with lies and misinformation. I only wonder if it could be possible to discuss the contributions of Jonas Wenström to the 3 phase system. Thank you and congratulations.
Thank you so much. I am sorry that I did not talk about Jonas Wenstrum who really was an important early inventor of three phase except that he didn’t get the opportunities that Dolivo-Dobrovolaky got. I mostly didn’t mention him because it felt like too complicated a story already. Still, I’m sorry about that b
@@Kathy_Loves_Physics Yeah, he died in 1893, the same year as ASEA finished their first commercial 3-phase power station. He seems to have gotten the exact same idea independently, but AEG seems to have been just a little bit ahead of ASEA.
Long live Dolivo Dobrowolski, Forget Nikola Tesla. This great discovery. Even greater than all the discoveries of Nikola Tesla. Well done, dear lady, for opening our eyes.
MISS KATHY thank you so much
Dear Lady, I love your videos they are about physics. I am a retired studio grip. I worked for years as a high rigger on many rock and roll shows.?My life often depended on gravity and our chain motors to overcome it. You are a great teacher!!! Dave. David M Holt, jr. Imdb
Thank you, Kathy. I'm a chemical engineer, and I find the history of science and engineering as the technology itself. I had not heard of Dovrowalsky or his contributions to 3-phase power.
Hi Karhy, I'm glad to see someone has finally created a channel around the history of physics. My name is Donald Chase, and I have worked in the electronics industry for 40+ years. I thought of doing the same thing that you are doing, but never got around to completing the work when I realized how much work it would take to put all of my knowledge into writing. I love the way that you are doing this. You kind of remind me of Carl Sagan in how you explain the subject so almost anyone can understand it.
Donald, please, reconsider. What better way than this to share your knowledge (40 years is a long time, a lot experience), and also to leave a legacy? I don't think you can reasonably not do this until you've picked just one thing, write, and then share it with us. Only then can you say no to the re. Yeah, you're right, writing about 40 years of experience is overwhelming, hundreds of videos. But just one? Surely you could do just one. There's a definite need for you to do this.
Even if it's a voice over with pictures explaining, because I'm camera shy can't focus right lol
Kathy, very good job, ("dobro") on historical popular facts about electricity and basic principles on how it works.
I do agree that many science giants (known and forgotten) on which sholders Nikola Tesla was "standing" to provide to hummanity the most efficient AC motor, should be noted in schools books. In Canada elementary/high schools only Edison is related to electricity in general not even Tesla.
James C Maxwell is regarded as a founder of the modern field of electrical engineering and sure in high schols he should be considered as one of 3 the greatest physics scientists in addition to Newton and Einstein.
Regarding Tesla, who helped you with your "eyes openning" facts agains him and being "Tesla nuts victim" to increase your You Tube chanell profit 🙂, you proved in the conclusion of this video with two papers: Nikola Tesla's 3 phase AC patent dated 1 May 1888 and Dobrowolsky's 3 phase AC patent dated 4 March 1890, that Nikola Tesla was the first and the most important 3 phase AC motor inventor and "gold winner".
Thank you and keep up doing good work!
This is perhaps the best explanation I’ve ever heard and I’ve heard no less than 50 on the minimum. Well done
Thanks.
Thank you for your video. You do an amazing job of tying loose ends together. When one gets more pieces of the puzzle fitted it make it much easier to comprehend the subject.
I've been binge watching your videos the whole week. They are entertaining and the knowledge sticks, is so much easy to remember who did or discover what, when put in context. Plus your love for the subject shows at every second. So glad I found your channel
This is absolutely brilliant work thank you so much for this video!
I love how well researched this was and that it highlighted a completely unsung hero of electrification that I was totally unaware of.
Thank you - so glad you liked it
With all the videos you've done, I am amazed this is a topic that hasn't been covered.
I know, it is a bit embarrassing that this is my 83rd video! Well, better late than never
@@Kathy_Loves_Physics I'm just grateful you did!
awsome!!! thanks for share that guy dobrovolsky was an amazing guy!
So amazing... Your channel so aptly demonstrates how to appreciate science and engineering and the enormous impact it has on our daily life which we accept matter of fact.
You have so beautifully summarised this in your closing statement...Dolivo Dobrovolsky demonstrated the first 3 phase motor and generator..
No mention of Jonas Wennström who had a patented 3-phase motor in 1890. He also helped to create the worlds first commercial three phase transmission line in december of 1893 (Hällsjön - Grängesberg line). His inventions helped found Swedish ASEA, that later became ABB
So who original invented 3 phase? Dolivo Dobrowolski or Jonas Wennstrom?
To my shame I had never heard of either Jonas Wennström or Mikhail Dobrovolsky. Both of their names should be up there at least with Edison or Tesla.
Kathy - Our ham radio repeater group had much discussion at one time on who came up with 60 Hz and why. I believe that the original Niagara Falls frequency was 16-2/3 Hz as it worked better for universal (AC&DC) brush motors. I think that is why the Pennsylvania Railroad chose 25 Hz for their electrification as well. Maybe also because there was less attenuation in the overhead and rails. Boy! This is interesting stuff.
Jim, the German rail traction uses 16.7Hz (1/3 of 50Hz), 15kV system. Interesting what you mentioned about Niagara Falls, maybe both have something in common as per engineering reason behind the frequency (series windings motors).
There are a few different rail traction systems in Europe, so many of the new locos are build to be universal thanks to silicone and asynchronous motors.
@@pliedtka Silicone keeps them lubricated. Silicon does the rectification. 🙂
Kathy I love your videos, love how you love physics and history! There is more to be learned here than meets the eye and ear. Your passion and enthusiasm for the subject is infectious!
Wow! This is so much more awesome in the details of how it all happened than the various books about Tesla that I have read. This clears away a bunch of the marketing hype and showmanship!
You are a remarkable young lady in the presentation of your podcast. 🎉
Check out the Lower Pelzer hydroelectric power plant. It went online in 1894 and still in operation. First AC powered textile plant with a 3.5 mile 3300v transmission line. Three 750kw units, one 250kw and one 1100kw. The first four were designed and built by GE and specifically Steinmetz at Mechanicsville. Four units have stationary magnetic poles with rotating AC armature and three 3300v slip rings. I believe this to be the oldest continuously operating power plant in the world.
Great stuff! There’s a lot of misinformation overhyping the achievements of Nikola Tesla recently. It’s nice to see somebody examine his contributions more objectively. He was certainly a great visionary, but the fact that he has a unit in the SI system, while Maxwell does not, is absurd.
I agree. Did you ever hear a quote about Maxwells laws from Richard Feynman where he said that it was the most important thing to happen in the 1800s and the Civil War pales in comparison? It’s a good quote
Worth pointing out, the Maxwell unit came first. The one named for Tesla came later.
gullenator1
'Some one' - NOT somebody
You will find every'body' in the cemetery
A BODY is a DEAD entity - {Latin} CORPUS - from which derives the word CORPORATION
- which is a DEAD entity and should always be written in ALL CAPS
a BODY is a DEAD entity - {Latin} CORPUS - from which derives the word CORPORATION
- which is a DEAD entity and should always be written in ALL CAPS
'One' is unique
'One is alive'
understand that there has never been 'one' like you before you were born
and there will never be another 'one' like you after you are DEAD.
You are 'one' of a kind ---- but.. Every'body' is the same.
Rotten and stinking after four days
-- Your third-world education system failed you - (By deliberate action)
And you failed to educate yourself.
Learn the subtle differences.
Also learn the difference between
APPLE and Apple
TESLA and Tesla
ON and on
TOYOTA and Toyota
ARMY and Army
NAVY and Navy
And many others that sound the same but they are NOT THE SAME
The problem here is that you and the majority were programmed to be ZOMBIES
- ZOMBIES have eyes but cannot see - ears and can not hear
The Programming - Indoctrination and PSYOPS has been largely successful
in dumbing down the population
Maxwell have he's honorable name for famous equations... This is a lot more than SI unit.
@@sasamladenovic6120 Having an equation you came up with named after you is pretty normal and has nothing to do with having a unit named after you which is a way of honouring you. It would be like saying, yes, it's a shame there is no street named after this author but all her books are named after her. Of course, her books are her books. It doesn't explain why no one thought she deserved to have a street named after her.
Looking forward to the Steinmetz presentation, his work on hysteresis was ground breaking and the use of phaser diagrams as a teaching and understanding aid for presenting complex ac interactions.
essential for a/c motors etc. unchanged in 120 yr.s
i believe time is a result of magnetic hysteresis
@@toymaker3474 see ken wheeler - you tube.....yeah....
Kathy, I stopped everything I was doing. Not only was your presentation articulate and wondrous, but the amount of research you must have done is phenomenal. I'd wondered about three phase all my life. Dad had a three phase motor out in his shop turning a fan blade to cool the place in Summer. All I can remember was that it scared my brother and me half to death--because when you hit the switch the thing went from 0 RPM to 2,000 RPM? in 1 second. The roar of the short, squat blade caused a terrific din that still makes me shudder to this day. The only thing I've seen spinning like that was the prop on a P-51D Mustang.
I've worked in industry as a maintenance technician. I've wired a lot of 3 phase equipment.
Although this video helped, I still don't fully understand 3 phase.... The person who trained me did explain a bunch, with a VOM, and how a single phase motor can run off of 2 legs of 3 phase. I also know well enough to just jog newly installed equipment to make sure it is rotating in the proper dorection. If not, just switching 2 of the 3 wires, it will ne corrected. I'm still baffled by it all, and proclaim myself a mechanic more than an electrician. Even 3 wire 220V in a home is a bit of a mystery... but I just installed 220V outlets for my welders... and everything works fine.
My home is in need of a pro electrician. When they show up, I will pick their brains...
Great video.... and thanks.