Improvements in and relating to stabilizing systems for synchronous dynamo-electric machines

摘要

547,622. Electricity supply ; automatic control systems for synchronous dynamo-electric machines. BRITISH THOMSON-HOUSTON CO., Ltd. Aug. 7, 1941, No. 10044. Convention date, Aug. 10, 1940. [Class 38 (iv)] The stability of synchronous machines is automatically maintained under varying load by means responsive to conditions indicative of approaching instability. The ratio between excitation and load may be maintained constant by a wattmeter element 9 operating in opposition to a solenoid 13 energized in proportion to exciting current and operating upon contacts 11, 12 in raise or lower circuits of a reversible motor which may be manually controlled to determine the setting of a field rheostat in the exciting circuit of an exciter 4. Alternatively, a contact operated by the solenoid may co-operate with a pair of contacts positioned in accordance with the position of the governor controlled throttle valve of the prime mover. The Specification as open to inspection under Sect. 91 describes a power factor relay adapted to energize the raise circuit of the motor when the machine is liable to be under excited, namely when the power factor in a lagging direction exceeds a value just below unity, thereby increasing the excitation of the synchronous machine. This subject-matter does not appear in the Specification as accepted.