How does an Induction Motor work ?

Please check out our new video on the same topic

Working of 3 Phase Induction motor is explained in this video with help of animation. They are the most commonly used electric motors. Here basic operation principle of an induction motor is introduced in a logical manner. Concepts of rotating magnetic field, synchronous speed and slip is well introduced in this video.

[SabinCivil]

Please check out our new video on the same topic

[brothermalcolm]

after googling and searching on youtube for about an hour for induction motor physics, and wasting brain cells on many poorly written articles (including wikipedia), i finally came across this brilliant piece of education. well done guys!

[jointdoggg]

how is it, that these youtube gods explain this stuff so much better that professors and doctors at the university?
5 minutes to explain 2 hour lecture.. thanks!

[alsfaa]

spending 5 mins here = whole semester to understand that from the lecturer

[tusharbansal]

Much better than my Professor at IIT. Thanks

[Cnctrldotcom]

An excellent introduction to induction motors. If I could suggest one improvement it would be season the audio liberally with "the" and "a"

[gordonbrown]

I think the description about emf generation in the squirl cage is slightly wrong. The induction of EMF and current in the squirl cage produces its own electro magnetic field. The South and North poles of this induced electro magnetic field in the squirl cage are then "dragged" behind the rotating stator magnetic field. In the video is makes it seem like the current creats the rotary motion directly while this is not the case. I think this is right, come some let me know if I have got that wrong.
Cheers

[patelvidhu]

Most simple and best explanation of induction motor. Thanks.

[yoda]

I usually don't comment on YouTube but this video deserves this very informative and conceptual.

[EJ]

Great, I understood many doubts around this topic. Just 4 minutes to solve it. Thank you. Vzla here!

[SelfEnergetic]

You explained the slip very well. Yes, no varying magnetic fields yields no induced voltage and hence no counter magnetic field or force to rotate the rotor. Hence, it slows down to gain another varying magnetic field. Thanks a lot

[NegenTropist]

There are *three points* that may lead to a better understanding of this beautiful video.

*Point 1*

The magnetic field lines of permanent magnets emanate FROM the North pole (by convention.)
In the case of RMFs (ie Rotating Magnetic Fields) the magnetic field lines are directed TOWARDS the North pole (by convention.)
These arbitrary definitions are put in place in order to make calculations easier!
The EXTERNAL region of a permanent magnet is USEFUL for our calculations. In contrast, the INTERNAL region of a RMF is the USEFUL one.
This is because induction motors and alternators DO NOT use the rotating magnetic field lines in the external space (say, outside the cage) for the production of useful work!
The above definitions ensure that we get the correct direction of the magnetic field in our visualizations and calculations.

*Point 2*

How do we choose the CORRECT DIRECTION of the induced (eddy) current *I* (blue arrow) in the CLOSED LOOP of 01:32 ?

Using our right hand, we _curl our four fingers_ following the direction of the induced (eddy) current around the loop. Thus, our *thump* shows the direction of the produced secondary magnetic field, which OPPOSES the RMF that created it, at the shown particular instance, according to *Lenz* law.
If the current *I* in the loop was taken in the opposite direction, then the induced secondary magnetic field in the loop (use the right hand rule as above) would REINFORCE the RMF that created it, thus leading to a flagrant violation of Lenz's law (violation of energy conservation!)

*Point 3*

Finally, having determined the shown *correct current direction* in the loop (blue arrow) we use *Lorentz's law* in order to determine the magnetic force direction.
Since F = q (vXB), we again curl our right hand fingers from vector *v* (current direction) TOWARD the *B* vector of our RMF and thus we correctly obtain the force direction (black arrows.)

That's all there is to it.

I hope I've helped...

[DrManuelKuehner]

Very good animation! I think the explanation is good/accurate enough to understand the basic concept. Thanks a lot!

[WXUZT]

Don't have words to describe this brilliant method of explanation.

[kevinbeckenham]

Very good basic lecture on electric motors

[tszkwanmui]

Clear explanation of the slip.
Highly recommended

[mikeyofficial]

I do electrical, and this video right here is good example on how motor works. keep it up.

[shoshohamad]

I am from Egypt, thank you very much for valuable information

[mrAmal]

LE is the super hero of engineering students

[mihavatovec]

Good teacher is someon who can give you all the answers to your questions