GB522011A - Improvements in and relating to electric inverting systems - Google Patents

Abstract

522,011. Converting. FRIEDLANDER, E. Nov. 30 1938, No. 34885. Convention date, Nov. 30, 1937. [Class 38 (ii)] In a polyphase inverter system of the type in which commutation is effected independently of voltage generated by external sources, stabilization of frequency or voltage is effected by associating therewith a parallel connection of saturated iron core reactor 5 and capacity 6 or a combination of inductive and capacitative elements having similar voltage-current characteristics, and means are provided for suppressing harmonics caused by saturation so as to obtain a sinusoidal output voltage. When operating on a fixed frequency, harmonic suppression may be effected by such resonant circuits. When frequency is to be varied, e.g., for motor speed control, methods of harmonic suppression depending upon multiple flux systems with suitable phase relationship therebetween are employed. For example, two sets of saturated iron core reactors 5, 7 respectively connected in star and delta may be used. In :an arrangement in which the capacitative and .saturated core inductive elements comprise respectively the commutating condensers and the supply transformer 5, Fig. 2, the secondary windings of the latter are arranged in tapped mesh connection with the two halves in opposite phase sequence. The inductive elements may, however, be formed by the load, e.g. motors with saturated poles and yokes. Regulating and starting problems are discussed at length in the Specification.