GB182478A - Improvements in or relating to alternating-current power transmission systems - Google Patents

Abstract

182,478. Metropolitan-Vickers Electrical Co., Ltd., (Assignees of Pierce, R. T.). June 30, 1921, [Convention date]. Dynamos and motors combined for transmitting power; regulation, automatic systems and apparatus for.-Relates to systems in which generators and motors are adapted to be connected in a number of wavs and consists in means for indicating the stability of excitation of the generators and for controlling this excitation whatever way the machines are connected. A three-phase system for electrically-propelled battleships is shown in which both generators 1, 2 can be connected up to all the motors 3, 4, .5, 6 with twenty-four poles effective, or either generator can be coupled with all the motors either with twenty-four or thirty-six poles working. To make the first connection, the generator switches 9, 10, the main switches 7, 8 and the motor switches 12, 14, 15 and 17 are closed, and as a consequence the auxiliary switches 82, 83, 80, 81, 85 and 86. The current transformers 35 and 36 supply current to the electromagnets 74 of the stability indicators 30 and 31 and of the relays 33 and 34, while the other elements 75 of these devices receive current from the autotransformer 42 proportional to the potential difference between the generators, the secondaries of the voltage transformers 38, 39 being connected to these elements 75 and to either end of the auto-transformer. Departure from mean stability causes one or other of the arms 56 on the relays to move into contact with a fixed arm 54 or 55 and complete circuit for electromagnets 59 and 60 which then complete circuits for the supply circuits 52 and 53 to operate the motors 44, 45 of the rheostats 27 and 28 whose variation affects the excitation of the field windings 21 and 22 of the generators. In all three cases the connection of the machines ensures through the switches provided that the stability devices will operate.