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Old 02-28-2009, 10:21 AM
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Jetijs Jetijs is offline
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Join Date: Aug 2007
Posts: 2,134
Here are some scope shots from my rotary attraction motor recovery:

But remember, those scope shots show the CURRENT and NOT the voltage. The measurements were taken across a low resistance resistor. There is the big spike and then we start to get some real current back. You can see the on the second picture, we get much more usable current out, that is because the first scope shot was taken from a setup with ordinary, thick iron plates, they did not demagnetize completely and there were losses by eddycurrents. Here is the setup:

Other scope shot shows improved results and I guess that this is because the shot was taken from the second motor setup which had a core made out of good quality silicon steel laminations. This is the second setup:

The operation of these motors is simple, we have bifilar coils on each pole. We let current to flow through one winding to build up magnetic field an attract the iron rotor poles. When the rotor poles are aligned, we cut off the current flow and capture the inductive spike in a capacitor via a high speed diode using the second strand of the bifilar coil.
Hope this helps.
It's better to wear off by working than to rust by doing nothing.
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