GB521314A - Improvements relating to regulating arrangements for electrical circuits - Google Patents

Abstract

521,314. Automatic regulation. HARMER, H. M., and CANUT, A. F. Nov. 15, 1938, No. 33229. [Class 38 (iv)] Constant current through a load of varying resistance is obtained by equal inductive and capacitative devices in series with a source of A.C. and means including one or more transformers or auto-transformers by which the voltages across these devices are opposed to one another in series across the load. Two transformers T1 T2 associated respectively with a condenser C<SP>1</SP> and an inductance L may be connected in series across the supply VS and in series opposition across the load R. The inductance may itself serve as transformer or auto-transformer and in certain circumstances the transformer T1 may be dispensed with. In order to limit the voltage occurring across a high resistance load and across the reactances the transformer T1, or a substituted choke or auto-transformer may be arranged to saturate at a given load resistance or reactance voltage since the current through the reactances varies with the load resistance. In the case of load resistances above their critical value a load circuit voltage which is constant and independent of load resistance and of supply voltage variations may be obtained by introducing by a transformer or auto-transformer supplied from VS an additional voltage into the load circuit. The load may be supplied through any kind of rectifier and two or three supply phases may by this means be paralleled on a load to provide a low ripple D.C. A two phase supply to a load may be obtained from a single source by taking a second circuit to the load through a barretter. The third harmoni in the circuit T1, C' may be reduced by a series circuit resonant thereto, e.g., by an inductance in series with the condenser C<SP>1</SP> across T1. The value of the constant current may be determined by the relative transformation ratio of the two transformers or by'a switch S, Fig. 2, whereby condensers may be transferred from one transformer circuit to the other, changing the effective value of the reactances while maintaining them equal.