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## Homework Statement

It is a question I asked to myself.

I studied the induction motor at school, and I asked to the teacher if it's possible to use magnets for build a reductor with magnets. She said it's possible but the energy lost in heating will be very high. I would like to know if my forces are correct and how to estimate the losses.

http://imageshack.com/a/img537/1866/zqaJ3k.png [Broken]

The Rotor1 rotates at 3w clockwise from an external device not drawn. The Rotor2 is push by the Rotor1. I guess the radius of the Rotor1 is 1 and the radius of the Rotor2 is 3. I would like to have w for the Rotor2, but I'm not sure if it is possible.

I have some questions:

1) I think it's possible to use it only if I start the device like I drawn, correct ? The magnet is pushing clockwise the Rotor2: the Rotor2 is acccelarating, the Rotor2 gives an energy to an external device (not drawn), magnets push counterclockwise the Rotor2: it is decelerating. The angular velocity of the Rotor2 is not constant but the mean can be at w, no ?

2) Losses are very high, even w is low ? How to estimate them ? In theory is it possible to have an efficiency of 1 with this reductor ?

3) Maybe this device exist, have you a link ?

## Homework Equations

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## The Attempt at a Solution

**I drawn forces:**

http://imageshack.com/a/img901/3278/NOjZYC.png [Broken]

My forces are correct ? The Rotor1 gives an energy F*r*3w*t and the Rotor2 can give F*3r*w*t, the efficiency can be at 1 only if magnets don't lost heating.

For me the angular velocity is not constant but like:

http://imageshack.com/a/img540/668/Pd5ALz.png [Broken]

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