Pulse Motors: MHOP #13: Rotorless MHOP No Rotor Motor
Here’s a demonstration of the operation of the Mile High Op Amp pulse motor driver without a rotor. The sense coil is positioned within the field of the drive coil and the setpoint threshold control is adjusted.
The driver produces the same kind of positive inductive collapse spikes and they can be siphoned off to power external devices or charge capacitors or batteries. It appears that there is even more power in the spikes produced this way than there is with the rotor in place.
This is an illustration of negative feedback (although I say “positive” in the video.) The building field in the coil is sensed by the sense coil and this tells the op amp to shut off the coil, producing the strong collapse spike. Reversing the field polarity or the sense coil produces a positive feedback oscillation at a much higher frequency (62.5 kHz) than what is shown here, but without the abrupt collapse spike.