GB630480A - Improvements in or relating to electric supply systems - Google Patents

Abstract

630,480. Automatic voltage control systems; boosting by transformers; supply systems depending on variable-speed generators. SIMS, R. F. Dec. 6, 1947, No. 32242. [Class 38 (iv)] In a supply system, comprising a variablespeed single- or poly-phase alternator 11, 15 supplying a relatively high power D.C. circuit 13, 14 over rectifiers 12 and a relatively low power circuit 20, 21 (which may include rectifiers 19) over a transformer 18, and in which the voltage of the alternator is automatically controlled, e.g. by a carbon pile regulator 16, 17, to maintain the high power circuit voltage constant irrespective of loading, variation of voltage in the low power circuit due to loading changes in the high power circuit is minimized by means which inject into the connections between the alternator and the low power circuit voltages which oppose the alternator voltage and are proportional to the current passing from the alternator to the high power rectifier. In the arrangement shown, injection is effected in the secondary circuit of transformer 18 by further transformers 25, 28; 26, 29; 27, 30, the primary windings 28-30 of which are energized from resistors 22-24 carrying the current of rectifier 12. In modified arrangements the secondary windings of the injection transformers are connected into the primary circuit of transformer 18; or the primary windings of the injection transformers may be connected directly in the alternator leads to the rectifier 12, the resistors 22-24 being shunted across the secondary windings.