Question

What if the BACK EMF was greater than inputed EMF, theoretically what would happen to the electromagnet? Would it just draw MORE current from the source, or would it just shut down, or would it possibly continue to work normally?

V.

Answer 1

@waterineyes @ghazi @henpen @Mikael @shivaniits @eyust707 @Jemurray3 @Carl_Pham

Answer 2

@zepdrix @AccessDenied @hba

Answer 3

Thank you! In advance :P

Answer 4

@ghazi

Answer 5

@Shane_B @Jemurray3

Answer 6

Any ideas anyone?

Answer 7

Um guys... Any thoughts about this?

Answer 8

If I understand what you're asking, then the back EMF can be likened to the drag on an object moving through a viscous fluid.

Answer 9

Nope, I'm asking what would be the result of the input EMF was less than the generated B-EMF this is not something common. That why I said "theoretically".

Answer 10

@Jemurray3

Answer 11

So, imagining we have a current loop with a voltage source of some kind, you're asking what would happen if the back EMF overpowered the voltage source?

Answer 12

Yes

Answer 13

I suspect that in a real circuit you would find that it would be rather difficult to generate a back EMF that was the same magnitude as the drive EMF but were you able to do so I would assume that current would flow for a short time until the back EMF ground the current to a halt. Because the back EMF is dependent on the current flow, if the back EMF overpowered the drive then current would stop and both would reduce to zero.

That's what I meant about moving through a viscous fluid -- that the drag force could be arbitrarily large due to the viscosity of the fluid and the shape up of the object but it will never actually drive the motion of the thing because it opposes motion.

Answer 14

@Jemurray3 Thanks for that.
Well, the thing is... Im working with magnets and electromagnets... I was worried about the B-EMF generated by the kinds of magnets I'm working with, with the same electromagnet... So I was wondering how is it possibile to manage this.

Answer 15

@Jemurray3 Im going to write another question that displays my idea and hope you can join and help me out with it! Its related to this problem.