GB313030A - Improvements in or relating to electrical power distribution systems - Google Patents

Abstract

313,030. Igranic Electric 'Co., Ltd., (Cutter Hammer Manufacturing Co.). March 5, 1928. Systems depending on two or more machines. -The motor M of a motor-generator set at an automatic substation is started under reduced voltage applied by an auto-transformer 3, 4 in response to the closure of a switch 12, the field F of the motor being shorted through a resistance R<1>. When the voltage of the generator G has risen sufficiently as ascertained by a relay 20, the starting switches 1, 2 are opened and the full voltage running switch 5 is closed, also the field F is connected across the generator 5. Should full voltage running connections fail to be established before the expiration of a definite interval after establishment of starting connections, a thermal relay 15 interrupts the starting connections. Thereafter, when the generator reaches normal voltage as ascertained by relay 21, contacts 22R, 22L close and connect the supplied conductor D to the generator through a resistance R9. If the resistance of the circuit C, D is sufficiently high, tripping coil 29 releases the locked-up switch 27, which closes, and short circuits a resistance R8 in circuit with the closing coil 25 of the circuit-breaker CB. The circuit-breaker is thereupon closed. An overload causes opening of contacts 26 in the circuit of coil 25.