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Q & A: ac magnet poles

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Most recent answer: 12/18/2011
Q:
Does an AC electromagnet have a North and South pole? If so, does it make a difference how the coils are wound (wound from one end of the spool only, not wound back and forth)?
- Roger (age 42)
Two Harbors,MN
A:
The north and south poles switch each time the current switches direction. For standard 60 Hz U.S. electricity, that's switching back and forth 60 times per second.

I'm not positive what your picture is of the different types of windings, since it's hard to describe without a sketch. It's important that each loop of the coil go around the same way, otherwise their fields cancel. Whether the loops start at one end and gradually wind toward the other or shift back and forth along the coil make only a subtle difference in the detailed field pattern.

Mike W.

(published on 12/18/2011)

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