Coil Question

[irvin]

I have searched around alot of boards about this coil question but just cant find the answer either im missing something or it hasnt been brought up it may sound silly but heres the question?

when building a stator why do the coils have to be bigger than the magnets? ive seen a few altered induction motors where the entire coil is covered by the magnet. Just wondering how much loss there is by making coils bigger, or what the reason by making them bigger is? Ive missed this part somehow.

I feel like this is silly but if anyone could point me to the link or give me explanation it would clears things up!

fixed now
Kurt

[Tritium]

Quite frankly with the vulgar username you have chosen I would boot you if this was my board.

Thurmond

[finnsawyer]

?  The coils have to be bigger than the magnets to get the loops of wire in there.  It is the change or rather the time rate of change in the magnetic flux contained by a single turn of wire as a magnet of one polarity (say north pole) gives up its place by the turn of wire to a magnet of the opposite pole (south) that causes the voltage.  This effect is known as "Faraday's Law".  Try to Google it.  I just did.  Got over 95,000 hits.  Have fun.

It should be fairly obvious that to get the maximum voltage you would want to have each turn of the coil encompass as much magnetic flux as possible.  That is, the entire area of the magnet.  If you make the inner diameters of the windings smaller and smaller  you will progressively lose more and more output voltage, but each smaller turn will have less resistance.  Somewhere in there between larger inner diameter coils and smaller inner diameter coils will be a "best" solution.  And there is certainly nothing that says you couldn't experiment.    

[irvin]

Thanks ill check that out