GB449424A - Improvements relating to rotary transformers for direct electric current and to apparatus for use therewith - Google Patents

Abstract

449,424. Electricity supply. GRAY, W. T., Darrooh. The Close, Altrincham, Cheshire, and METROPOLITAN-VICKERS ELECTRICAL CO., Ltd., 1, Kingsway, London. April 24, 1935, No. 12387. [Class 38 (iv)] Systems depending on two or more machines.-In a starting arrangement for a D.C. rotary transformer of the " metadyne " type in which a regulator machine RG is coupled to the transformer shaft, a relay N1 sensitive to the voltage and speed of the machine RG controls the operation of contactors LS1, LS2 connecting the " metadyne " machine MD to the line. Closure of a switch S, Fig. 2, energizes a relay R1 and operates a switch r1, Fig. 1, connecting the machine RG to the line in series with a resistance X1. When the speed reaches a predetermined value contacts n1 Fig. 2, of relay N1 are closed and energize a relay R2, Fig. 2, whose contacts r2, Fig. 1, short circuit the series resistance X1 and contacts r2<1> insert a resistance X2 in series with the coil N1 contacts on the relay R2 also control the closure of contactors LS1,LS2. Contact r2 is arranged to close before contacts r2<1> open. Should the speed of the machine MD drop relay N1 drops away to disconnect the machine from the line and contacts r2<1> are arranged to open before contacts r2. In a modification, Figs. 3 and 4, closure of a switch S energizes relays R1, R3, Fig. 4, whose contacts r1, r3, Fig. 3, close to connect the machine RG to the line in series with a starting field F2. A shunt field F1 controlled by a resistance X3 is provided and the relay N1 is connected in series with a resistance X4 across the machine RG and field F2. The initial large current in the machine RG operates a relay N2 connected across a series resistance X1 and opens its contacts n2 in the circuit of a relay R2 in parallel with relay windings R1, R3. When the speed reaches a predetermined value relay N1 operates and closes its contact h1 in series with relay R2 and at the same time relay N2 is de-energized by decrease in armature current to close its contacts n2 to energize the relay R2. Contacts r2, r4, r5 are closed, contact r3 is opened and the line switches LS1, LS2 are closed. Contact r2 short circuits the starting resistance X1, contact r3 short circuits all or part of the resistance X3 in the circuit of the field F1, and closure of contact r4 and opening of contact r3 connects the coil N1 in series with F2 which is ineffective and the machine RG is connected in series with a field F3 and a regulating winding RW on the main machine MD across the line. Fall in speed of the machine MD causes release of the relay N1 and return of the circuit arrangements to the starting conditions. Specifications 403,464, 417,517, and 424,082 are referred to.