When electromagnets are used in a motor with a duty cycle of 50% or less, you have the opportunity to collect the power that was used to power the electromagnet the next time it is used.  Instead of charging batteries you collect the energy in a capacitor instead.  It is best to do this where the electromagnet and capacitance value are operating at a resonance point with each other.  This requires complicated computerized circuitry to do this at an optimized functional circuit for changing load conditions.  By switching in steering diodes into the circuit, the direction of the electron flow can be controlled allowing for more slop in the capacitors values in the circuit.  Because of this, simpler circuits can be used to change the variable capacitor in the circuit.  The four drawings show the circuits function of capturing and re-using some of the electrical energy used in one electromagnet function to be used again in the following electromagnets function.  So if the circuit captures 50% of the energy from the electromagnet to be reused in the next cycle and it takes 30% of energy to operate the the TANK and variable capacitor circuits, that means you would be operating the motor with 80% of the energy if you did not have the circuits.  This circuit would be used with high efficient motors in order to improve their performance.

Please resize as it is way too big to see.

I have resized the drawings and added a drawing of a variable capacitor circuit.  This circuit would be needed for sure without the steering diodes.  With the steering diodes, you may get a way with selecting the value of the capacitor for the worst case operational condition after the motor is brought up to speed.  At start up, the switches of the tank circuit could be set to operate the motor from the power supplies.  This simplifies the circuitry that would be needed for a the control system of the motor assembly.

The Lunkster