# Eddy current - magnets.

1. Dec 7, 2009

### gareth01422

Hi guys

I may have posted in the wrong section.

If I have 2 magnets pushing away from each other (one is fixed) the other is on a crank. And the crank is spinning around 2000 RPM (33.33 crank rotations every second) how will eddy current effect the 2 magnets?

I have Wikied "eddy current" and read the page but still dont understand how this would effect my mind experiment.

Can someone explain it to me in simple terms?

Gareth

2. Dec 7, 2009

### Per Oni

Do you mean the eddy currents running in the magnetic materials? If so then I don’t think they will be big because the electrical resistivity is quite high for those.
Having said that you’ve got quite a speed. To work out the voltage each time the magnet cycles you could perhaps wind a search coil with say 10 windings or more and look on an ac meter what the generated voltage is. (divide again by 10 or more).
Then you have to estimate the resistance of where ever the currents are running. If they are running in a copper plate then they will be high. As usual I=U/R. This will give you a rough idea.