Abstract: A multiphase, synchronous, electrical machine with a permanent magnet incorporates a stator winding that is supplied with power through a static converter in such a way that, apart from the primary excitation field produced by the permanent magnets, there is an additional magnetic longitudinal field that is generated by the armature winding through which current flows, this additional longitudinal field being added to or subtracted from the primary excitation field in the longitudinal axis of the pole, and in which there are permanent magnets arranged within the winding-free rotor, as well as soft magnetic materials with intervening spaces of non-magnetic material which form loops that lie within each other and that are open towards the air gap, enclosing the air gap.

Abstract: To keep the voltage rating of the components of a static converter as low as possible, the permanent magnets of a permanent magnetically excited converter-fed synchronous motor with a preferred direction of rotation which are mounted on circumferential surface of the soft-magnetic part of the rotor have a thickness which, along the line of the magnetization, increases from a first entering edge to the other leaving edge of the permant magnet with the thickness at the first edge being nearly zero. The magnetic air gap increases from said first edge to the adjoining pole gap. The supply currents having rectangular time patterns are controlled in accordance with the position of the rotor so that the electrical loading is routed only along the q axis.

Abstract: A compressor arrangement for a heat pump installation in which an electric motor is provided as the drive means for the compressor is disclosed. In order to make possible operation of the compressor without unpermissibly large surge currents in the electric network supplying power to the electric motor, the compressor is driven by a permanent magnet-excited d-c motor which is provided with an electronic commutating device. The starting current drawn by the d-c motor can be controlled by means of a d-c voltage control element coupled to the electric network by a rectifier so as to prevent unpermissibly large starting surge currents.

Abstract: In a commutating device for an electric motor which is supplied from a d-c voltage source, which includes semiconductor switching elements arranged in a bridge circuit and addressed by means of a control voltage in dependence on the rotor position of the motor, in order that the semiconductor switching elements can be addressed without transformers and without separate control voltage sources, the residual voltage dropping across the load circuit of the semiconductor switching elements and/or the inverse voltage stored in the respectively preceding cut-off phase is used as the control voltage.

Abstract: A method and apparatus for utilizing the waste heat energy of an internal combustion engine in which a turbine is driven by the exhaust gases from the engine and drives an electrical generator. In order to permit a direct coupling between the turbine and the generator and to utilize completely the electrical energy recoverable from the waste heat energy, the generator is a synchronous machine with a non-wound rotor, the generator being connected via an electrical converter to an electric motor which is drivingly coupled to the internal combustion engine to relieve the load therein.