GB767318A - Improvements relating to alternating current supply systems - Google Patents

Abstract

767,318. Supply systems for consumption apparatus. WESTINGHOUSE BRAKE & SIGNAL CO., Ltd., and KING, K. G. May 13, 1955 [June 1, 1954], No. 16190/54. Class 38 (4). An alternator 1 having a relatively high internal impedance Z supplies a two-stage magnetic amplifier in which the greater part of the alternator output current is taken by the second stage over lines 5, 7, this stage constituting a waveform distorting load. An impedance Z<SP>1</SP> is connected in series with the circuit connecting the alternator to the second stage, the impedances Z, Z<SP>1</SP> having substantially the same phase angle. The first stage across lines 6, 7, is connected to the alternator through the secondary winding 4 of a transformer 3, the primary winding 2 of which is connected to the terminals of the impedance Z<SP>1</SP>, the transformer being so connected and of such a ratio that the voltage injected into the circuit of the first stage is equal and opposite in phase to that developed across the impedance Z. In this manner, the unwanted coupling between the load causing distortion and the other load is reduced or eliminated whereby non-linearity in the response of the amplifier is prevented. The impedance Z<SP>1</SP> may be equal in magnitude to the internal impedance of the source, in which case the transformer has a transformation ratio of unity. If the impedance of the source is substantially inductive, the impedance Z<SP>1</SP> and the transformer - 3 are replaced by a quadrature transformer, Fig. 2 (not shown). A voltage regulator may control the voltage applied to the first stage of the magnetic amplifier.