GB207843A - Improvements in automatic or remote controlled rotary converter substations - Google Patents

Abstract

207,843. English Electric Co., Ltd., and Schroeder, G. Aug. 5, 1922. Synchronizing dynamo-electric machines.- In an automatic or remote-controlled substation, a rotary converter adapted to be started up at reduced voltage from the alternating-current side has its field winding excited from a separate low-voltage source so as to avoid the necessity of splitting the field winding at starting; the number of turns of the field winding is substantially smaller than would be required for the selfexcitation of the converter. In the example shown, the exciter 6 is mounted on the shaft of the converter 1. The secondary windings 8, 9. 10 of a three-phase transformer are, each connected at one end to a slip-ring 4, and at the other end to a switch contact 11; an intermediate point in each secondary is connected to a contact 18. At starting, the arms 12 contact with the points 18, and the machine accelerates to near the synchronous speed with a reduced voltage applied to the slip-rings. The switches 21, 20 are automatically closed in succession so that the voltage of the exciter armature is impressed or the converter field winding 5 through the resistance 19. The bar 20 is then moved until the switch arm 13 connects with contact 17 and short-circuits the resistance 19, and a moment later, the arms 12 connect with contacts 16 so that the full voltage is applied to the 'iprings through the small resistances 15; further movement of the switch cuts out the resistances.