Pulse Motors: MagSpinner 1: Input Power Measurements

Here I show an input power measurment on the MagSpinner v1. The difference between the power input when magnet is spinning, and when it’s not, is demonstrated.

I put a 1 ohm current viewing resistor in series with the coil to monitor the current waveform. The coil is being fed with a 20 v p-p sine wave from the Interstate F43 High Voltage function generator. At the test drive frequency with the magnet spinning, the current trace from the CVR indicates a sine wave, phase shifted by about 30 degrees, and with a magnitude of around 175 millAmps p-p.

Now the fun part: I stop the magnet with a finger. What happens to the input power when the magnet is not spinning? The input power actually goes up.

So…. if the coil is consuming a certain amount of power without spinning the magnet, and consumes less power when it IS spinning the magnet, does that mean that spinning the magnet is not only “free” but actually produces net power?

This isn’t at all the same thing as the increase in power draw from a siezed armature in a normal commutated DC motor. At least I don’t think it is.

Feel free to discuss, and provide plausible explanations for the phenomenon demonstrated.

You may also like...