GB559701A - Improvements in and relating to dynamo electric machines - Google Patents

Abstract

559,701. Exciting alternators. PARTINGTON, W., and METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. Aug. 26, 1942, No. 12059. [Classes 35 and 38 (iv)] An alternator 1 feeds through a condenser 3 into a load 6, the voltage across which is maintained substantially constant and independent of the load current by a device which automatically controls, in accordance with the voltage across the load 6, the direct current flowing through the exciting winding 7 of the machine, the direct current being obtained by a rectifier 9 to which alternating current is supplied by the machine. As shown in Fig. 1, control is effected by an automatic regulator of the carbon pile type, the resistance element 8 of which is in series with the winding 7 and the operating coil 11 of which is supplied from the load terminals 4, 5 through a rectifier 12. Excitation current is obtained from an auxiliary winding 10 on the machine, the coils of this winding being located either in the same slots as the coils of the main winding 2, or in different slots preferably spaced 90 electrical degrees from the slots of the main winding. In a modified construction the excitation current is obtained from a step down transformer connected directly across the main winding 2, whilst in further constructions the main winding comprises a number of groups of coils distributed over the winding being connected through the rectifier 9 across one of the groups. The alternator may be constructed as described in Specification 557,968.