GB500265A - Improvements in electric measuring and controlling apparatus - Google Patents

Abstract

500,265. Power meters; electricity, supply. BRITISH. THOMSON-HOUSTON CO., Ltd., and T1ATH1'aWS, P. Aug. 5, 1937, No. 21631. [Class 37] [Also in Group XXXV] The difference between the power outputs in watts of each of a number - of parallelconnected generators, transformers, or other circuits and the average power output of the remaining circuits is directly indicated or supplied to relays for controlling the outputs of the separate circuits. As shown, alternating current generators A, B, C are connected in parallel to supply a load circuit D. The output circuit of the generator A contains a primary winding of a current transformer T having two secondary windings T1, T2. The secondary winding T2 is connected through a balancing resistor R to the current winding I of a wattmeter or relay of the centre zero type, the voltage, winding V being connected to an auxiliary bus-bar E connected to the circuit D through a potential transformer F. An auxiliary D.C. supply G connected to the moving contact of the relay supplies energy for controlling the governor adjustment. Similar current transformers, relays, and connections are provided for the generators B, C. The secondary windings T1, T<SP>1</SP>1, T<SP>11</SP>1 are connected in the series additive circuit R2 representing any number of similar additional equipments. The number , of ampere-turns of the secondary windings in each current transformer connected in the series additive circuit is so arranged that the resulting flux just neutralizes the flux in the core produced by the primary output current of its generator when this is supplying the average output. If the generator output is greater or less than the average, the difference flux energizes the current coil of the wattmeter or relay. Specification 17199/09, [Class 38 (iv)], is referred to in a disclaimer.