GB632918A - Improvements relating to the operation of a polyphase electric motor from a single phase source - Google Patents

Abstract

632,918. Induction machines; phase-changing. BRITISH THOMSON-HOUSTON CO., Ltd., MAGGS, A. H., and CHOUDHURY, S. U. A. July 24, 1945, No. 18930. [Classes 35 and 38 (ii)] [Also in Group XXXVII] Suitable operating characteristics for a three-phase induction motor, which is supplied through terminals 8 and 9 from single-phase mains 1, 2, are afforded by means of a capacitor 6 and a saturable ironcored reactor 7, which are connected in parallel across motor terminals 8 and 10. The reactance of the combination of the elements 6, 7, varies with the applied voltage, the reactor being designed to become saturated at a voltage substantially equal to that obtaining across terminals 8, 10, when the motor is running at normal speed and load. The winding of the induction motor may be delta-connected (Fig. 2, not shown), or star-connected for starting and delta-connected for running (Figs. 3, 4, not shown). Reversal is obtained by connecting the capacitor and reactor to a different pair of motor terminals, such as 9 and 10 in Fig. 1. The number of turns of the motor phase winding 4 may be made smaller than that of the windings 3 and 5. In this case reversal is obtained by connecting another pair of motor terminals to the supply-lines. Specification 630,007 is referred to.