Wheelchair electrical control circuit

Abstract From the Canadian patent

The normally provided manually operable switch lever on an electrically drive wheelchair incorporates pairs of switch arms so that additional circuitry can be provided for interconnection with the normally provided left and right wheel drive motors. This additional circuitry comprises electrical resistances arranged to be connected across the motor leads by the manually operable switch when in an unactuated position for the particular motor in question. The provision of these resistances across the motor leads when the motors are unenergized results in absorption of back voltage spikes to thereby avoid burning out the switch means dynamic braking when the motors act as generator as a result …