02 - Why is 3-Phase Power Useful? Learn Three Phase Electricity
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- เผยแพร่เมื่อ 15 เม.ย. 2018
- Get more lessons like this at www.MathTutorDVD.com
Here we learn why 3 Phase Power systems are useful for supplying large blocks of electricity and for supplying power to rotating motors. We learn that when you calculate the total power delivered to a motor over the three phases, the total power is constant even though each phase has a time varying power component.
This means that the motor will run more smoothly with less vibration and is why in practice three phase motors are commonly used in industrial equipment.
This is great teaching. I am a retired Chemical Engineer who worked in the Power Generation industry. I have specified and purchased numerous High voltage , 3 phase motors during my career. I know all the necessary mechanical aspects to specify a high quality, reliable motor (like a Siemens motor) but none of the electrical theory behind the motor design. These lectures are great at filling in the gaps. I have a lot of respect for EE's. Their mathematical skills put them at the top of the engineering food chain. My son is one. He uses control theory to define many forms of human behavior.
You are an amazing teacher. I wished I had a lecturer like you. Great job.
I've been studying electrical theory for 2 years and electrian for 10 years cannot believe what I'm seeing right now in just 35 menuts. I salute you sir, thank you so much👍
Why don't you add one diagram showing the three phases along the Xbox axis with phase starting at 0 degrees then phase b starting get at 12.0 degrees and phase c beginning at 240 degrees this may help people visualize the three phases at no load.
My new favorite channel...
Tremendous instructor. I love that he offers "proofs" in great detail for every statement he makes. Too often, professors/teachers/instructors make profound statements, only to lose their students by not fully explaining the content. I've been an instructor/teacher for over 30 years (flight instructor, main occupation is engineering) and have reduced learning to 3 steps: explanation (explain the content), demonstration (demonstrate the content), simulation (apply content to real world scenarios for deeper understanding). To me, this is how this man teaches. No part of his lesson is left undefined or lacking in demonstration.
He should give lessons to educators on how to teach... IMO.
I agree with you.
This is the core of teaching!
Some 'teachers' can give excellent textbooks explanations. (theories)
That's it!
Some 'teachers' can give awesome demonstrations. (examples)
That's all!
Some 'teachers' can give an exciting simulations. (applications)
That's all!
Theories reinforced by examples with real-world applications really highlights knowledge that leads to a deeper understanding!
I'm fueled to teach!
i love these lessons. You've done such a good job, you've made them easy to listen to, to understand and enjoyable. All the other tutors on the net I've seen so far can make it seem so much more challenging and confusing. Congratulations on doing so well and making them free and available for anyone to use. You deserve all the credit you can get.
If I had teacher like you in my school/ college days ! Thanks a lot -- from India.
Hiki kipindi ni kizuri sana,nimejifunza kiurahisi mfumo wa umeme mkubwa na faida zake na kwanini ndio unaopendekezwa katika kuendesha mashine kubwa,Thank you so much.
Jason's method of teaching is absolutely phenomenal. In this lesson in particular, I have never actually had a professor explain the motivation in the real world to use 3-phase power over 1-phase power.
I stumbled on this channel. I am 70 and have a PhD which was in Fourier theory. I have worked in defence scientific organisations with some top class electrical engineers. This guy provides an insightful practical analysis of why 3 -phase is fundamental to motors which is far better than many TH-cam pretenders. He has thought this through very well and the maths he gives is sufficient to understand why it works although students should actually perform the algebraic steps to prove the constancy. It is not hard but character building nevetheless. Well done.
Thank you so much! I really appreciate you taking the time to write this. Take care, Jason
This is teaching maths and science to the layman at its very best. Congratulations! I am loving it!
best explanation I have come across on the internet
Wow. I really like the analogy of three people pulling a rope. Thank you so much!
that pulley analogy of 3 phase power might be the pov i was looking to throroughly comprehend this concept... great job
I love this video. I earned a BSEE 43 years ago, and I must have learned all this at some point, but you made it so clear.
Now I'll have to watch the rest of your series and learn:
1.) Where did the 60° come from?
2.) How is it implemented?
3.) How did someone figure this all out to start with?
I learned more than I had expected from this single video about 3 phase circuits. The explanation is so clear and vivid. Thanks!
I love the three one-armed man analogy at the end. “... and a threefold cord is not quickly broken.”
5y
Ty
I never had any training in this field but always have the curiosity to learn. My work experience with power is minimal at best in a large hotel. I watched two back to back videos on 3 phase and have to say this instructor did a great job getting me to understand the lessons. I was lost with wave frequencies and some terminology but quickly picked it up. Watching a few videos that explained 3 phase before this helped.
Your explanations are so clear and easy to understand ! Thank you and good work .
This is a gem! I can't emphasize this further. To those who can relate to why I am saying this, I'm happy youtube lead you to this video. What a superb way of explaining how efficient 3-phase power is compared to single phase in the application of motors and its accompanying varying vibrations should a person opt to use single phase.
Excellent analogy at the end.
With all the respect, it is the best explanation ever, I m an electrical engineer and up to this moment, I really understand why it is so useful to shift to the three-phase power system. Thank you
it was great.please show it practically for the next program to be diverse thank you so much
I no longer fear the topic of three phase electricity! Great video! Thank you so much!
you're a life savior !!!
Also with a balanced three-phase motor, the bearings and bushes don't wear out unevenly due to any vibration or shaking...
Great analogy using the hoist! It's been years since I covered this in class but I do remember coming away confused. Not now! Thanks!
Great analogy at the end with the engine hoist, well done.
EXCELLENT, SIMPLIFIED AND CLEAR EXPLANATIONS, CLARIFICATIONS AND PRESENTATION! THANK YOU
Thank you for this video, I've been solving these in class with no understanding of what is going on but now it's perfectly clear, I also loved the final analogy
Another way of looking at it: going back to the vector diagram. Say the "unwanted vibration force" generated by the 'phase a' vector = F.
The component of the 'b' phase vector in the direction opposite the 'a' vector, equals (opposite over hypotenuse) or sin30degrees, = 0.5. So the force = 0.5F. Same for the 'c' vector. Therefore 0.5F + 0.5F =F, but in the opposite direction to the "a" phase.
Therefore the forces cancel.
All three vectors of course rotate around the zero point at the intersection of the axes, but maintain their 120 degree separation relationship.
So unwanted vibration forces cancel out in 3-phase motors & generators (to a large extent, anyway).
This video was very good and I enjoyed understanding the resultant power output due to capacitive and/or inductive reactance.
At the end, you added 3 instantanious apparent powers (from 3 different sources of voltage or windings). I think you can add only true powers (watts) in this case. That means adding 3 squared sine, which gives a constant wattage (1.5x individual peak wattage). The force supplied through 1 turbine is only for total watts which is constant.
You explained & demonstrated the subject matter very clearly & succinctly. Thanks for posting.
Excellent . Beautifully explained concept of 3 phases and its importance.. M.zakir Pakistan 🇵🇰
I plotted all the power curves using the Desmos App on my phone, very interesting to see the resultant power curve move up and down when varying the phase from -90 to +90.
Thanks, it was great watching your videos very informative and simple to understand
Thank you sir for such a detailed simplified explanation.it makes me understand electrical Engineering better.
Thanks, really help understanding the new concept that not mentioned in our class.
for the first time in 10 years i am seeing why 3 in a motor. good guy!keep it up dont Die of COVID -19
this is actually the first video I've seen on youtube that explained the REAL reason why to use 3 phase power: it's because you have continious power. but still missing: why? the reason was in the invention of electric locomotives. locomotives drive a steel wheel on steel rails - this is slippery. if you start to slip because of high power peaks you go from friction coefficient to slip coefficient - so you lose the ability to create pulling force. but with continious power you don't have those peaks and an overall higher power and you create more pulling force.
Almost the reason for 4 x 4 trucks. No?
RubyRhod IDK, It may be true, but 3-phase predates that application. The tech was invented by Nikola Tesla, who was working with Westinghouse to establish the first semblance of the modern electrical infrastructure we have in world today, with large-scale power generation and long-distance transmission. 3-phase induction was probably the final, key piece that made the system viable based on AC current.
1) Is a shift of 120 degrees required, or is it possible to talk about N-phase power where N is greater than 3?
2) I understand that 3-phase power provides constant power, compared to single phase. This discussion reminded me of rectified DC power which also provides constant power. Would it be fair to say that the purpose of 3-phase power is to provide constant AC power like DC but without the need to rectify?
Excellent video. Thank you.
Great explanation! You may want to consider using the trigonometric identity for cos(a)cos(b) = 1/2(cos(a-b)+cos(a+b). It makes it much easier to see the real and imaginary components of the the instantaneous power.
I really appreciate it!
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always the best lesson thankyou for the effort
Very good. Might be an idea to show the vibrations both in single phase and 3 phase motors (?!).
I love this guy!! Great tutoring vids!! Thank you.
stumbled on your chanel,you are a great comunicater of physics,really good rythm and pace in your dilivery,and internation
that is perfact,and your passion shines through,best ive seen,you have inspired me,thank you,great job.
The analogy at the end is PHENOMENAL in case you don't get it already
I really appreciate that.
This guy is a totally LEGEND!!
We're all happy to see a flat-line... when it comes to electrical motors and not muscular ones.
I'm really loving your videos. What do you think of using - for your final analogy, a single cylinder engine and a three cylinder engine to represent power /time? Btw. I'm making my son watch your videos... thanks!
Well presented using a classic ‘on the board’ presentation technique. While the constant output power for motors is well described, it has only recently become practical to do it for things like traction motors for road vehicles, or trains, with variable frequency 3 phase motors.
However (when there was no use of such 3 phase motors - low frequency single phase was often used), one of the early reasons for using 3 phase transmission that was explained to me by a lecturer was the economy with regard to the amount of copper, or aluminium cable needed for a given amount of energy, especially bearing in mind that real cable has an element of resistance -> thermal loss in transmission.
cheers sir, thanks for the lesson, i have open my mind clearly,. God blessed u =))
I at times got lost especially with the maths calculation where I am not the best but it was worth watching the video clip. I studied to become an electrician in the 80's and to be honest there was more writing to be done . I think overall you have done a good job....Well done Sir.
Excellent!
when are you uploading other videos with wye and delta etc
Very helpful👌
Thank you very much, Sir. A good explanation. I got it.
great video
Great video. This helps me understand why Tesla's induction motors work. Induction motors are amazing.
You're a heckuva teacher. Thanks.
Great! This was absolutely amazing!
Thank you Sir,easy to understand.
Please Jason, can you bring us Fourier Analysis and Fourier Transform
Great explanation!
I love the way you teach. How can i follow your previous and succeeding lessons in 3 phase electricity?
thank you so much. you took much time and explained it so nicely..... once again thanks a lot
Yep ... the real deal ... that's why I purchased the lessons online.
The formula P= vi = i^2R already tells you it is dissipated energy in the form of heat which is caused by the collision among free electrons in the resistive load, and the whole conducting circuit. Their collisions cause frictional forces which converts electrons' kinetic energy into thermal energy
You can have zero phase(Φ=0) only when you have a circuit in resonance in which both voltage and current signals are in phase. It's better to use sine function graph to express AC with the initial voltage value = 0
Your videos are great a little constructive criticism louder mic I had my radio on full blast trying to listen to you and I barely could hear you! Thanks for your help
I love this guy!
Best teacher I've ever listened to we'll educated man on electric
So happy you liked it!
Jason, MathAndScience.com
Dear,sir. You are excellent teacher, l wish alway to listen to you .
Awww thank you!
14:30: "Inductors and capacitors are probably manifestations of the same thing, seeing as how electricity and magnetism are so tightly bound together." Intriguing statement. I'd love to hear any ideas you might have about this, because it's really messing with my head.
THANK YOU...SIR...!!!
Requires more reviews...!!!
Thank you, great information
Thanks. From Bangladesh.
Ecxellent explanation...thank you so much---
Thank you so much!
Jason, MathAndScience.com
Excellent teaching sir 👌👌👌
Great video
Excellent
Loved your explanation. You mentioned using multiple windings as a trade-off for using three phases sources. is it possible to have all three balanced sources connected in series so that they can automatically add up before being delivered to a single winding?
Amazingly beautiful teaching Sir, Even a dinosaur like me can understand it..studied these fundamentals in 1972 2nd yr college..thank you n more power( 3 phase) to you sir..😀
Help at 3:52. If I went to phasor land and multipled the original volts time amps I would get V*I@angle(thetaV+thetaI). After doing the phase shift (and the formal published power formula) I am now at (thetaV MINUS thetaI). How do I reconcile this mathematically
Thank you!
You are a real hero!
Proud of u!!
Peace
awsome analogy！！
I'm looking for the next sequence to this video ,can anyone please help?
polyphase (three-phase in this case) quite simply because single-phase machines in motor or generator operation are an energy catastrophe (see Leblanc's theorem on rotating fields). They are limited to low powers
I can't say the words ..its awesome & amezing
Thanks!
@@MathAndSciencefrom your channel i started learning yesterday onwards. i started from Engeneering circuits V1 & i listened first 3 lessons.it was amazing & then after 4th lesson onwards (from power calculation) it was completely incomplete upto 20th lesson.May i know what's the reason...
Do you have a video on phase angles?
Very good. Does this implies that 3 phase supply would not be suitable to run Non Rotating type appliances like lights, power sockets?
Thank you man
Thank you for this video sire. It was very helpful and efficent👌.
To show that in three phase the power pa+pb+pc=constant, we may use fresnel construction? (using the projection of rotating vectors)??
Can anyone tell me from where can I get full electrical engineering course explained by this professor!
Without stating the obvious how good these lessons are, but I don`t have to well of wiring on motors never a good under standing on ohms law but I would like your opinion on this question please. What is better `in torque to use a 3 phase motor with the correct rating capacitor wired to it and wired up correctly for it to run as a single phase on a 230v-240v electricity
Or a single phase 230v-240v motor on a 230v-240v
Good stuff! ... however, did you not forget to say that, in order to obtain a constant value, Pa, Pb and Pc should be summed in quadrature, that is you should take the root sum of the squares (RMS)?
Beautiful
Excellent presentation but was wondering how much more power does three phase give compared to single phase
Wonderful explanation for a non-engineer. But in the more general case, homes can also be supplied by 3-phase power. Does 3-phase power offer advantages for circuits without motors?
I think the curent should be a wine function if the voltage is a cosine because they are complementary are they not?
excellent