Abstract: A circuit arrangement comprises an inverter with two parallel switching branches which are connected to a DC voltage source and each of which comprises two series-connected switching members, each of which comprises at least one switch and an anti-parallel connected diode. A switching member in one switching branch each time constitutes a diagonal pair in conjunction with a switching member in the other switching branch. A load with a given polarity is connectable to a DC voltage source via the diagonal pair. The voltage on the load temporarily becomes zero upon the change-over from one polarity to the other. A control circuit is provided for opening and closing the switches in a manner such that the switching members are successively switched on and off.

Abstract: A circuit arrangement for powering a two-phase asynchronous motor having two windings which each have one end connected to one anode and both have another end connected to a third node, the nodes each being arranged to receive one of three alternating voltages whose sinusoidal fundamental waves at least substantially correspond in frequency. In this circuit arrangement, the power dissipation in the switching circuit connected to the third node is reduced by the alternating voltage applied to the third node having constant levels in periodically recurring time intervals so as to obtain a more economical dimensioning without a deterioration of the operating characteristics, particularly the loadability.

Abstract: A circuit arrangement for commutating a reluctance motor including a current generator which produces first and second cyclic sequences of current pulses. In response to the first cyclic sequence applied to the stator windings of the motor, a rotor travels a predetermined distance along a motion coordinate path. Application of the second sequence to the stator windings results in the rotor traveling at least twice the predetermined distance along the motion coordinate path. The second sequence, which is applied when rotor speed exceeds a predetermined level, is formed by omitting predetermined current pulses from the first cyclic sequence.

Abstract: A circuit for controlling a free-piston engine, particularly of a refrigerator compressor, includes a bridge circuit part (1) of H configuration, in the sides (4, 5, 6, 7) of which there are positioned electronically controlled switching elements (8). The part of H configuration (1) is connected to an engine (10). A microprocessor (17) is provided to control the opening and closure of the electronic switching elements in accordance with the measurement of the mains power absorbed by the engine. The circuit provides elements (23, 25) for measuring the absorbed mains current traversing the diagonals (4, 7; 5, 6) of the H part (1), said current being proportional to the mains power absorbed by the engine (10). The elements (25) feeds a signal to the microprocessor which, on the basis of this signal, generates a further signal which, by comparison with a value equal to the current actually absorbed by the engine, enables the electronic switching elements (8) to be controlled.