GB523755A - Improvements in or relating to electric power systems - Google Patents

Abstract

523,755. Transmitting mechanical power. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. Jan. 13, 1939, No. 1255. Convention date, Jan. 28, 1938. [Class 38 (iv)] In a system in which a prime mover drives a main electrical generator, an exciter and an auxiliary generator, the means for controlling the prime-mover also operates a generator regulator system by which, over the lower speed range, a differential control is exerted on the exciter to limit the torque on the prime mover, while, over the higher speed range, the field of the generator is controlled so as to attain maximum torque. The auxiliary generator may function as a speed indicator and controller over the higher range and also serves to charge a battery and drive auxiliaries. The primemover 22 is directly coupled to the generator 9, the exciter 13 and the auxiliary generator 17, and is regulated by control lever 33 connected to switch contacts 35, 34 by which the two control ranges are rendered effective. For starting the prime mover, switch 37 and push-button switch 39 are closed thereby supplying current from the battery 24 to the starting field 12 of the generator. When the engine is started, switch 38 is closed, whereby relay 27 and voltage regulator 25 are energized thereby connecting regulating resistances 45, 46 in or out of the circuit of the shunt field 21 of auxiliary generator 17 to secure constant voltage for charging the battery 24. When the prime mover is driven up to about half speed for supplying the motor 23, contacts 34 are closed by control lever 33, thus energizing relay 36 by which the field 15 of the exciter 13 is connected across the battery, whereby the exciter 13 energizes the field 11 of the main generator 9. Variations of the current in the main circuit between the generator 9 and the. motor 23 act through the opposed or differential field 16 of the exciter to limit torque resistance of the generator. When running at higher speeds the engine control 33 also closes contacts 35 thereby operating relays so that controller 25 is de-energized and controller 26 is brought into operation by connecting its winding across the auxiliary generator 18. The voltage of this generator 18 then varies with the speed and it controls the operation of relay 26 by which switch 29 is opened or closed to regulate the resistance in the field 11 of the main generator 9 and secure maximum torque at all speeds.