Abstract: A motor-compressor unit of the type in which a compressor piston is driveable by the eccentric of a motor shaft of a two pole D.C. motor. The starting characteristics of the unit are improved by off-setting phase-wise the torque developed by the motor from the torque required to drive the compressor.

Abstract: The invention relates to a control circuit for a brushless type DC motor of the type having a permanent magnet rotor and a pair of poles provided with two windings, the windings having a common junction which is connectable to the positive terminal of a DC voltage source. A pair of controllable switching elements are in respective series with the windings. A symmetrical square wave pulse generator responsive to the angular position of the rotor switches the switching elements on and off in a push-pull mode. The control circuit processes the square wave output and has dual outputs for driving the switching elements with the dual outputs having alternate pulses in time spaced relation to each other for driving the switching elements in underlapping relation to each other to prevent the elements from drawing current from the common junction at the same time.

Abstract: The invention relates to a self-starting electric motor assembly of the type having a permanent magnet rotor, a stator with two windings and electronic switching elements for the windings controlled by switching signals occurring in push-pull and derived from control signals of a sensor detecting the angular position of the rotor. At standstill and for normal running operation the magnetic field distributions between the stator and rotor are selected in a known manner, so that the rotor assumes an angular position which is displaced in relation to the neutral position as an aid to starting and so that the switchover occurs at an angular position ahead of the neutral position to provide greater efficiency for the running operation.