120/240 and 120/208 Volt Transformer Secondaries
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- เผยแพร่เมื่อ 16 ส.ค. 2020
- Explanation of how we derive 120/240 V and 120/208 V from various Transformer Secondaries.
Additional video of interest: "120/240 V In-Phase or Out-of-Phase" • 120/240 V In-Phase or...
PLEASE NOTE: The arrows above the left schematic show that this is one winding that has simply been tapped in the center. The waveforms below it in the lower left can give the wrong impression that the "halves" of the winding are out-of-phase with each other. This is because I'm using the neutral as a reference and as I mention in the video, from the perspective of the neutral you look "up-arrow" to one end and "down-arrow" to the other end of the winding. BUT, from either end (i.e: black wire to red wire, or vice-versa) you will be looking "up-arrow" or "down-arrow" for the entire length of the winding (i.e: in-phase).
You can dig through the comments for further discussion on this. I have made a video addressing the phase relationship within 120/240 V systems, and I hope to create other videos focusing on current flow in each of the scenarios that will further our understanding of these transformer configurations.
Thank you,
Dave
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This man is a master at teaching... so clear. his body movements, his eye movements , hands all work in coordination with each other. his voice, easy on the ears... His brain the conductor of the whole operation. A pleasure to learn from...Thank you Dave.
Yes sir!! 🧑🏻🏫
Rolling my eyes
Dave taught at my JATC for a couple years. He’s literally the only reason about 40 of us made it past our second year.
I get the same vibe. This man knows how to teach well.
Sheesh .....get a room 😆
Truly a master in explaining, makes it easier to understand the concepts
I am electromechanical engineer, your explanation is very very clear. THANKS a lot teacher.
Thank you, as a mechanical engineer I’ve always struggled with electrical concepts and this helped me understand much more about how the different windings affect voltage.
As a EE, I have to commend you on a well diagrammed and spoken lesson. Good job!
The 120/240V thing was actually a late 19th century thing - all derived from the Great Fire of Chicago. Edison lamps were made out of carbon, and used 110V, however, other companies figured out how to make lamps using tungsten, a much more resilient metal and could work at 240V (carbon lamps burn up at 240V). Since adoption of electricity was much slower in Europe, the European utilities went with 240V as it saved money on copper and is more efficient. Our 110V system was derived as a split-phase system, because Edison noticed that some people's lights were brighter than others. So he designed the system as two 110V generators (this was DC, mind you) and connected them together to form a third neutral line. He realized by monitoring the current flowing on the neutral line, he could determine how bad the imbalance was and rebalance the grid so the same number of lamps were on each half so everyone's lights were the same brightness. In addition, if you needed more power, you had 240V (DC) available.
Now, electrification was huge in the US - especially after the Great Fire of Chicago which meant everyone started from scratch, and skyscrapers were a thing. Gas lamps couldn't be lit more than a few stories up, and everyone wanted electric lighting. So much so that demand for light builbs was so big even though carbon lamps were obsolete, Edison was still making millions of them as the tungsten lamp makers couldn't keep up (in the late 19th century, they made around 10 million tungsten lamps, and Edison made nearly 60M carbon lamps. This changed about 20 years later in the early 20th century when carbon lamps were finally obsolete and replaced with tungsten lamps. However, by now the die has been cast - 110V had been around for so long, there was no appetite to change over to 240V..
In Europe, electric lamps were seen as a novelty, and very few people had it. The rich folks refused to install it in their castles, so when it came time, it was trivial to switch over.
Oh, and the first war of the currents was between Edison and Westinghouse, not Tesla. The second war of the currents was between GE and Westinghouse which dictated if we'd use two-phase (Westinghouse, via Tesla's patents) or three-phase (GE, Edison had been kicked out) AC. Tesla is confused in these because Westinghouse bought Tesla's AC motor patent (and later all of Tesla's patents). That patent showed how a motor would work at 60Hz two-phase. You have to remember though, that just because of this, power was still not quite standardized as you could get DC, 60Hz, or 133Hz AC power (133Hz because Westinghouse managed to find a design for an electric meter but that required 133Hz to run properly).
133Hz from my understanding, was more commonly used with carbon arc lamps common for streetlights and in factories and large retail stores from the early 1880s until the early 1900s, because it flickered less than 60Hz. You also had very oddball frequencies such as 25, 33.3 & 40Hz, to name a few. The early days of electrification must have been a very intriguing time to live through. And all this was in major US cities, many farms and homes in rural areas didn't have electricity until after WWII, my grandmother recalled not having electricity until merely a few months before she married in 1947, born in a farmhouse in 1925 and lived to be 96.
Other than you kept referring to the peak voltages as 120V which would be confusing to a beginner when actually Vp ≈ 170Vac or Vp-p ≈ 340Vac hence the need for capacitors with 370V or 440V ratings.
Root Mean Square is just the DC equivalent hence there would be a straight line drawn through the sine wave to represent that average. Vrms = Vpeak/√(2). RMS is the only way to average a sine wave in case your wondering. It's also used to take an average in statistics to minimum the effects of outliers 😉
- 1st drawing - Single Phase
- 2nd drawing - Three Phase (Wye)
- 3rd drawing - Three Phase (Delta)
I suggest adding "Ugly's Electrical References" book to your toolbox because it covers all this and much more in case you forget.
Great video 😊
i feel lucky that people like dave are on youtube and shares their knowledge, great info!
I was so lucky to be in his classes. Dave, you rock, man.
This man is a truly gifted teacher!!!!
He just schooled me so good!
Thanks sir
We love ur videos
His diagrams are perfectly simple
This is one of the best videos I have watched out of a lot out there that explains with this much clarity and expertise. Thanks for passing your knowledge how it should be with all.
Nice work Dave. This is one of the most thorough and understandable descriptions on 120/240 and 120/208....excellent.
Thank you, Dave! I've just discovered your videos while looking for some information about transformers. You combine two of my favorite subjects: electricity and math. Fifty years ago I was an electrician in the Navy. At that time, we were trained in single phase and three-phase delta and wye transformers. I understood it completely at the time, but never had experience with them since then and lost my knowledge of them. Now I understand them a whole lot better.
Dave your videos are so immensely understated. You're an absolute hidden gem and I can't thank you enough for making this material available. I'm an IBEW electrician apprentice in my 3rd year and I constantly supplement my school work with your videos.
Dave, I was looking for the definition of a great teacher, and now I got it on this TH-cam video. You are beyond excellent and keep up doing this amazing teaching style.
You have simplified months of frustration in trying to understand these concepts. I cannot wait to check out the rest of your videos. I so appreciate the clarity you deliver. THANK YOU!
Wow I wish I had a teacher like you when I was in trade school, nice job explaining and simplify something so complicated, please continue uploading videos!!!
Sir, you're a teaching machine! You managed to master all your techniques magnificently. Thank you for that
Searched for this explanation for way too long. Very well done Dave.
The clearest instruction / explanation I have ever seen on this. Great video
I like the idea of the radius of a circle in terms of a generator, starting from west or zero axis , like a radar from west , north , east , south and to west. !
Radar or radius is from center point to the inner circumference of the circle ⭕️ . Diameter is from west to east or north to south, that is why a radius really is interesting like radar !
I've been digging to find a good explanation and now I've found it. Thank you sir!
Dude. This is awesome. Great way of explaining it. I totally get how this works, but being able to explain it is very hard for me and this way of explaining it is perfect.
this is literally the best explanation ive ever heard for this.
Amazing explanation, very good job 👏
I'm blown away by your efficiency sir! All the little comments added explaining things for our green compadres shows how masterfully you teach. Thank you sir.
Thank You Dave well done! Best teacher I seen yet! Thanks again.
Best explanation ever. I finally understand!!!!!!!!!!
Thank you.
Wow you are amazing! Thank you so much for making this video. I will share this to all my friends.
Glad to hear someone use the correct definition of voltage. It is the "difference of potential" between two points.
Seriously, this guy has mastered the description of *why* 208v.
Great people share their knowledge!!! God bless you!
Excellent video that explained some of the lingering questions I had regarding electrotechnology. Thankyou Dave!
Wonderful info, thoughtfully and clearly laid out
Great teaching skills. You making it very easy to follow. Thank You 🙏🏼
I liked this guy the moment he spoke. You can tell a great teacher within seconds. God bless S.T.E.M.
Amazing explanation!
I like the way you teach this topic. Thanks for sharing knowledge.
Excellent presentation Dave, was a joy to learn from ya
Fantastic video! I recently took over management of a 160 year old theatre that has a high leg delta panel in the projection room. Wanted to get familiar with the system. This video was incredible informative. Don't be worried. It did not give me the the confidence to monkey with the panel. I'll call a pro anytime this panel needs works.
Absolutely immaculate explanation
This is the best explanation I have ever seen.
Very good explanation. Crystal clear tome
30, 60, 90 degrees and you get 208. Wow, I never realized that trigonometry and electricity were connected!
I'm about to start my second year of school and man am I glad I stumbled on your videos
Very good explanation/tutorial. Thank you for sharing.
what a master class. an absolute pleasure to see it
Very Informative! Easy to follow!
Wow, this was super helpful. Thanks for posting this.
fantastic job explaining this topic
Thank you so much for your crispy clear explanation! This helped me so much, awesome!
Thanks from Austria for the teaching - work. 🙏
In Germany, the middle circuit is used, the Y circuit.
Transformer voltage from hot to neutral is 230V and from hot to hot it is 400V.
THANK YOU, I APPRECIATE YOU. Im literally sending this to few of my classmates and couple of my electrical friends
You are way better than any professor I know. I graduated with EE from college also.
Awesome job explaining
Excellent teacher! That was great explanation, made it look so simple even though it ain’t. 👍👍👍
Awesome job of explaining 120/240 and 120/208 theory 👍
Amazing explanation. Thank you!
Truly outstanding lesson. Thank you.
Thank you Dave, easily explains the differences as well as applications. And thank you for the math lesson (brings back memories).
Amazing video and explanation
Clearly explained. Really helped what i was looking for
Excellent explanation
"Hot water heater". (snicker, chortle, guffaw). Perfect lesson, yet again.
Good info, thanks for putting this out here for people to learn from.
Excellent video!!!! For the case of the delta transformer. As we can determine the current in each winding to determine the single-phase and three-phase load distribution in them and thus their optimal size, this in the case of being a bank of transformers.
This was excellent. Thank you!
Your the best thanks so much for simplifying this process.
Thank you for a additional knowledge it's very important specially in my daily operations. Electrical lineman here in the phillipunes thanks a lot.
Your explanations are clear
My God I needed this refreshing course I'm am definitely enlightened
Excellent instruction, and a perfect example of how clarity doesn't require fancy animation, just a clear grasp of subject, words, and pictures.
Now for the love of all that's decent and proper, stop saying _"hot_ water heater", and change that "HW" to "WH". You don't need to heat hot water.
Thanks for your kind words and your attention to detail with "HW" and "WH". I will take note of this for future use as I have to agree fully with you.
Also, thanks for engaging with B YENZER1's comments as I have been unable to allocate much time to reviewing comments, but you will notice that I have added a somewhat lengthy comment to your last one.
p.s. By the way, since we're trying to be decent, proper, and particular with words, which phrase do you use? "I could care less" or "I couldn't care less"?
@@davegordon6819 - Well first of all, I never claimed to be decent and proper myself, so my phrasing is usually more colorful than either of those options. But I'm told by my neighbor who is an English prof and historian, that "I could care less" is the _older_ version of the two, contrary to common misconception. It was as if to say "You think I care very little now, well if you like, I can care even less." Only later did people misunderstand it as an error, and decide that it should be "couldn't care less".
@@pterafirma I've never heard that explanation so you (and your neighbor) have given me my new piece of knowledge for the day. Now I can go take a nap.
Thanks again.
Awsome video, really enjoyed it
Great teacher. Awesome job
Thank you for excellent lesson
Well done. And I actually saw the fireworks first hand at work when one of the guys installed a bunch of new 120 V fluorescent fixtures to a 208V high leg by mistake. WE also had 277 VOLT stuff that people made mistakes with. Luckily we worked for BIG OIL. They could afford it.
My favorite term for the high leg of a delta transformer for 120/240 is the "bastard leg."
Another EE here, and I like your teaching style, you dive just deep enough into the theory for the non-mathematically inclined to still understand the important concepts. It would be so easy to try and "prove" that you know the theory, but at the risk and expense of losing your audience, and that makes a poor instructor! You make it easy for those just beginning to learn the electrical trade to understand. Nice work!
Amazing instruction.
Very good work there
Great video, very clear..thanks!
Good teacher. Love it!!
This is some high-quality content here! Thank you so much for making this video! It is extremely helpful.
Excellent class!!!!
Thanks for explaining a different method to calculate the HIGH LEG to ground. I did not know using Pythagorean theorem gives you 208AVC. I've always use Vector addition.
Thanks! great Video!
Subscribed! love your videos
I did the HW chum
rms = root means square
center neutral opposing and pushing relativity of product
Bus wiring
Voltage = Points if differential potential of to points (Check out angle theta!!)
as well as from which 120 degrees of the exact moment of the circuit became energized comparing the constant peaks per delegated cycle (Alternating Current and it's Value) while subbing out impedance with greater use of Volts and VA (Volt Ampere) to mediate or use the Load (What the conductors are connected two and their rating) for treatment of the new simulated
resistance from use of Center Tapped Neutral
Connecting within the center if the Wye Connect will split...not only the windings but the voltage.
Equaling=B phase To High leg is 208V
Make Sure You label!
Excellent video!
Yes, the center tap of the secondary winding (neutral to ground) is both positive and neutral (at the same and time)
You're a very good teacher. I've been trying to find someone to explain this to me for awhile now, searching all over TH-cam and the internet in general and haven't found a single person that can explain this in a manner that I could understand until I seen this video. I appreciate that you took the time to make this. Thank you.
Thank you for helping me understand the wye out of phase 208 and the delta ! My teacher could use some lessons from you on explaining things better!
Beautiful
Big help!! Thank you!
Thank you very much!
Great video sir
Amazing content and speak ability.
In my country the voltage between the phase and the neutral conductor is 230V +/- 10% and between any two phases it is 400V. Every other house has a three-phase connection.
Clear and enjoyable!
Thank you! Really gonna help me with school