What is the formula that determines the power output one would expect

to get by rotating a magnet within a coil ? Say I have a coil with 100

wraps and a magnet at 1 Gauss and I rotate that magnet at 1000 rpm

within the coil... what will be my power (voltage and amp/watt) output

?

1. IF I KEEP ALL THE SAME:

But double the MAGNETIC GAUSS (to 2 GAUSS) how much more power output

can I expect ?

2. IF I KEEP ALL THE SAME:

But double the RPM of the magnet (to 2000 RPM) within the coil, how

much more power output can I expect ?

3. IF I KEEP ALL THE SAME:

But double the coil (to 200 wraps), how much more power output can I

expect ?

I'm trying to understand the ratio and relationship (in power output)

between RPM, Magnetic Strength and Coils.

Thanks,

J.

Faraday's law of induction points out that you can get a *voltage* if you

change the magnetic flux through a coil. The formula is

V = N * dF/dt

where F is the magnetic flux in webers, and N is the number of turns in

the coil. Unfortunately, you can't directly relate gauss to webers

unless you know the geometry of the situation.

So, given my shaky understanding of the subject, I believe that you can't

know the power with the information given for several reasons:

voltage cannot be related to power without knowing the impedance.

You don't know the rate of change of magnetic flux, because we can't

calculate the flux without knowing the geometry.

That being said, you can see that if you double the magnetic flux density,

then the rate of change of flux as the coil rotates will double. This

means that the induced voltage will double, and since power is related to

the square of voltage, the power transferred will quadruple.

Doubling the RPM will also double the rate of change of flux, causing the

same result.

Doubling N will again double the voltage, causing the same result...

--

Regards,

Bob Monsen

"I am a strong advocate for free thought on all subjects, yet it

appears to me (whether rightly or wrongly) that direct arguments

against christianity & theism produce hardly any effect on the public;

& freedom of thought is best promoted by the gradual illumination of

men's minds, which follow

~~ from the advance of science. It has,~~

therefore, been always my object to avoid writing on religion, & I

have confined myself to science. I may, however, have been unduly

biassed by the pain which it would give some members of my family, if

I aided in any way direct attacks on religion"

-- Charles Darwin