GB228551A - Improvements in and relating to systems of electric distribution - Google Patents

Abstract

228,551. British Thomson-Houston Co., (Assignees of Stewart, G. E.). Jan. 28, 1924, [Convention date]. Systems depending on the use of two or more machines.-In systems in which an independently energized circuit 3, is to be supplied also from a source such as a generator 1, means are provided to allow supply from the generator but only when its voltage exceeds that of the circuit by a predetermined amount. With the circuitbreaker 2 open and switch 28 closed, the ungrounded side of the generator is connected to the mid-point 23 of the operating and controlling windings 11, 12 of a directional relay 7, such as is described in Specification 182.769, [Class 38 (v), Electrc switches &c.], the winding 12 is therefore across the terminals of the generator and the operating winding is between the ungrounded sides of the generator and the circuit 3. With these conditions the armature 8 will turn counterclockwise against the spring 21, if the generator voltage exceeds the circuit voltage by the predetermined amount, and close the contacts 19. 20 to complete the circuit of the closing coil 6 of the breaker 2. so that the generator can now feed the circuit. But closure of the breaker opens the contacts 22, so that the generator no longer feeds the coils of the relay 7. which are then in series and fed from the circuit 3 so that the armature is turned clockwise to open the contacts 19, 20. Closure of contacts 24 as the breaker closes, completes a circuit for the closing coil 6 in shunt to that through the contacts 19, 20, and containing, if desired, the contacts 25 of an overload cut-out 26.