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The back motor effect (see Counter-electromotive force) is the counter torque which opposes the rotational motion of the coils in a generator when the generator is under load.

The back motor effect depends upon the load connected to the generator. The more load, the more current will be produced which will increase the counter torque. But to produce more current, the normal torque will also increase. So, shouldn't this balance the effect? If it does, then why do small generators change sound (nearly shutting down) when load in increased on them?

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Is your question why the generator slows down under load? If so, then think of it as a brake: if you brake harder the rotational speed decreases. – Alexander Apr 24 '13 at 16:05
I think you should re-write your question. I'd edit it to do it for you but I'm concerned about possibly changing the meaning. If you're asking why load on the generator increases when the electrical load increases, I'm interested too. – Brandon Enright Apr 25 '13 at 3:46
Yup @BrandonEnright i am asking the same question. – Rafique Apr 25 '13 at 21:36

1 Answer 1

A small shutting down on increasing resistance because the small generator has no ability to produce such current to perform such load. If the load is equal to the ability of the generator then it will not shut off.

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