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Q & A: simple generator

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Most recent answer: 07/03/2008
Q:
I would like to magnetize a propeller/impeller, insert it into a water pipe, then wrap the outside of the pipe with copper wire. Will the flow of the water rotating the magnetic propeller/impeller generate a current? If it will, I'll have a few more questions. Thank you.
- Kenji (age 49)
Napa, CA
A:
It sounds like the  propeller will rotate about an axis down the middle of the pipe. If the coil is simply wrapped around the pipe in the obvious way, rotating the propeller won't change the magnetic fluc through the coil, so it won't generate any electromotive force. You may need to use several coils wrapped in loops around axes pointing in toward the pipe. Then if the propeller is magnetized with one tip N and the opposite tip S, you'll generate an ac EMF in each coil. With a little circuitry (full-wave rectifiers) and you can get a dc voltage out to drive a dc current.

Mike W.

(published on 07/03/2008)

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