GB440635A - Improvements in or relating to the automatic frequency regulation of alternating current supplies - Google Patents

Abstract

440,635. Automatic reversible motor regulators. GENERAL ELECTRIC CO., Ltd., Magnet House. Kingsway, London, and GIBSON, J. W., c/o General Electric Co., Ltd., Witton, Birmingham. March 20, 1934, No. 27347 /35. Divided out of 436,574. [Cla.ss 38 (iv)] The frequency of an A.C. generator is controlled by means responsive to integrated frequency error and means responsive to the load demand of the generator are arranged to exert a control tending to prevent alteration of frequency as a result of variation in the load demand. The frequency of an A.C. generator is varied by a reversible motor 54 acting on the engine governor under the control of contactors 49, 50, which are operated by " raise " and " lower " segments 40, 41 on a drum switch 38 which is rotated by a synchronous motor 29 driven by the generator. The brush 44 coacting with a continuous segment 39 on the switch 38 is energized from supply 19 through contacts 14 of a telephone relay which are closed intermittently by a master clock 3 so that when the frequency is correct the contacts of relay 14 are not closed when brushes 45 and 46 are on their respective segments 40, 41. Positive or negative integrated frequency error causes contacts 46, 41 or 45, 40 to be closed at the same instant as contacts 14 are closed thereby to control the governor motor 54 to decrease or increase the speed of the prime mover. The arm carrying the brushes 44, 45, 46, 47 of the controller 38 is adjustable in accordance with the position of the governor through the medium of torque motors 59, 60 and the arrangement allows of an integrated frequency error dependent upon the generator loading. This ensures suitable load sharing between parallel connected generators. An intermediate torque motor 73 is inserted between the motors 59 and 60, which is controlled in accordance with the generator load from a repeating watt meter 77 so as to prevent alterations in frequency as a result of variations in the load on the generator. Lock out contacts 42, 43 on the controller 38 effect control of warning or protective devices when the integrated frequency error exceeds a predetermined value. Interlock contacts 51, 52 are provided on the contactors 49, 50. Specification 407,401 is referred to.