Abstract: A simple and economical system for operating a dc. motor of the permanent magnet field type from an ac. supply, characterized in that the motor may be driven at an adjustable speed in a forward direction by energization through a controlled half wave rectifier (e.g., SCR) or at a fixed, high speed in the reverse direction by energization through a half wave diode rectifier.

Abstract: The converter includes a dc. motor energizable from a battery and adapted to drive an alternator which produces an ac. output voltage for powering a load device. When the switch of the load device is closed or opened to start and stop the latter, the motor of the converter is automatically energized or de-energized. A unique system for controlling automatic energization and de-energization of the motor is constituted by low cost and reliable components and is characterized by a voltage divider and a diode circuit which (1) cause battery current to flow through a pick-up resistor to effect starting of the motor when the load device switch is first closed, and (2) limit the current through the resistor to small values when the alternator is operating.

Abstract: The converter includes a dc. motor energizable from a battery and adapted to drive an alternator which produces an ac. output for powering a remote load device. The latter is adapted to be connected to the converter by a three-wire extension cord having a ground wire for grounding the load device. A manually operable switch is located near the output end of the extension cord and is connected across the ground wire and one of the conducting wires of the cord. The motor of the converter may be started by momentarily closing the switch and may be stopped when the switch is next closed momentarily.