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# OCR B = Rotating field motors and Fleming's hand rules. watch

1. The book has confused me big time on rotating field motors. (Advancing Physics A2 pg.139) How do you get the field to rotate in the stator? And where do the coils go that carry away the alternating output?

Or even better can someone just explain everything about how a rotating field motor works? I find it hard to translate the book sometimes. XD Any help would be very appreciated, thankyou.

Also, what is the difference between Fleming's left hand and right hand rules and how do you know which one to use?

Thanks.

EDIT: Oh yeah, and is the transformer rule Vs/Vp = Ns/Np as the book says or Vp/Vs = Np/Ns as the revision CD says?
2. (Original post by bmatboy)

EDIT: Oh yeah, and is the transformer rule Vs/Vp = Ns/Np as the book says or Vp/Vs = Np/Ns as the revision CD says?
I'm not doing OCR, so I don't have the book, and nor do I refer to anything as a rotating field motor so I'm not 100% sure what you mean there. Also I tend not to think of the Flemming rules as two separate rules so I won't confuse you if you do, but...

Vs/Vp = Ns/Np

Vp/Vs = Np/Ns

3. (Original post by Spenceman_)

Vs/Vp = Ns/Np

Vp/Vs = Np/Ns

... oh yeah... LOL XD Whoops, silly me.
4. (Original post by bmatboy)
The book has confused me big time on rotating field motors. (Advancing Physics A2 pg.139) How do you get the field to rotate in the stator? And where do the coils go that carry away the alternating output?

Or even better can someone just explain everything about how a rotating field motor works? I find it hard to translate the book sometimes. XD Any help would be very appreciated, thankyou.

Also, what is the difference between Fleming's left hand and right hand rules and how do you know which one to use?

Thanks.

EDIT: Oh yeah, and is the transformer rule Vs/Vp = Ns/Np as the book says or Vp/Vs = Np/Ns as the revision CD says?
Vs/Vp = Ns/Np or Vp/Vs = Np/Ns

They are the same thing, they are just ratios!

Induction motor, there's a good summary of what they are on the p140 of that A2 Advancing physics book.

Basically, the relative motion of the rotating magnetic flux in the stator and rotor induces an large current in the rotor.

(if the magnetic flux in the rotor was rotating at the same rate as the rotor no current would be generated - this is why this doesn't happen)

The large current in the rotor causes 'poles' to be set up in the rotor

These pole are attracted to the 'poles' on the stator (see the diagram on p.140 and you'll get what i mean)

This attraction force generates a force that causes the motor to rotate.

Btw, i'm not learning those hand rules... i never seen a question on it!

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