GB822530A - Voltage regulation arrangement for contact converters - Google Patents

Abstract

822,530. Rectifying. BROWN, BOVERIE & CIE A.G. May 22, 1957 [May 24, 1956], No. 16284/57. Class 38 (2). A contact converter with switching chokes 11, 12, 13 having control windings b, d carrying constant A.C. and variable D.C. respectively, has in parallel with its contacts 21, 22, 23, circuits including valves 31, 32, 33 and impedance 7 so arranged that at the instant of contact opening the current flowing through the parallel circuit is equal in value to that flowing through the saturable reactors whatever the value of control D.C. and consequent setting of magnetic phase angle control. The valve anode voltages are derived from transformers 41, 42, 43 energized from the main A.C. supply through transformer 17 and D.C. generator 14. The control D.C. and valve anode voltage are thus varied together as resistor 9, which is in series with starting rheostat 10 in the supply to exciter 15 of motor 16, is controlled by the output of D.C. transformer 8 in a connection to the main rectifier load 3. The voltage or power output characteristic of the rectifier is thus determined by the control D.C., and it is shown by means of diagrams (Figs. 3-6, not shown) how, as the value of the positive current steps varies with change in the control D.C., the value of current in the parallel circuits changes in agreement. The grid voltages of the valves 31, 32, 33 comprise bias from the D.C. exciter 15 and voltage generated in windings C on the switch chokes. The generator 14 may be replaced by a transductor (Fig. 2, not shown).