GB729512A - Improvements in or relating to an electrical generating system - Google Patents

Abstract

729,512. Automatic voltage control systems; commutating poles. LEECE-NEVILLE CO. Jan. 12, 1953 [Feb. 1, 1952], No. 849/53. Classes 35 and 38 (4). In an automatic voltage control system for a variable speed D.C. generator having both shunt field and commutating pole windings and in which vibrating contact regulators control the output voltage and current, the commutating poles are provided with additional windings energized so as to increase their field as the speed of the generator rises. The generator 10 supplies a load through normal commutating pole windings 23, 24, the operating coil 41 of a current limiting regulator and a conventional cut-out 14. The shunt field winding 21, 22 is in series with resistors 40, 46 controlled by vibrating contact voltage and current regulators 12, 13. Each commutating pole, Fig. 2 (not shown) has an additional winding 25, 26, assisting the normal winding and connected across the resistor 40. As the generator speed rises, and consequently the voltage tends to rise, so the regulator 12 inserts resistor 40 into circuit for increasing periods, hence the excitation of winding 25, 26 increases to increase the commutating pole field. In modifications, Figs. 3 and 4 (not shown), the additional winding is in parallel or in series with 16 shunt field, and opposes the normal commutating pole winding. Hence as the speed rises, the shunt and additional fields are reduced and the effective commutating pole field is increased.