Patent GB-222994-A (GB)
Title: Improvements in and relating to automatic reclosing circuit breaker systems
IPC: H02H3/06
Filed: 1923-07-24
Abstract: 222,994. British Thomson-Houston Co., Ltd., (General Electric Co.). July 24, 1923. Protective arrangements.-In an automatically - reclosing circuitbreaker system which comprises a supply circuit and a number of feeder circuits, the arrangement is such that in case of an abnormally heavy overload on any feeder the corresponding circuit-breaker together with the supply circuitbreaker are opened. The opening of the supply circuit-breaker de-energizes the holding coils of all the remaining feeder circuitbreakers and a reclosure takes place first of the supply circuit-breaker and then successively of the feeder circuit-breakers. Each circuit-breaker is provided with means for preventing any further reclosure after it has been opened a predetermined number of times. The supply circuit. 1 with the circuit-breaker 5 is connected by bus'-bars 3 to feeder circuits 2, 2' provided with circuit-breakers 6, 6<1>. The circuitbreakers are provided with operating mechanisms of the type described in Specification 217,417, each being provided with a toggle 10, 11 .arranged to be overset by a cam 9 on a motordriven shaft 20, a link 16 being adapted to be obstructed by the core 13 of a holding electromagnet 14 so that the circuit-breaker may be forced against spring means to the on position. Associated with each circuit-breaker are an overload relay 26, a control relay 28 and a notching relay 32. These relays in the feeder circuits are fed from control bus-bars 56 adapted to be connected by relay 48 to control bus-bars 22 for the control relays of the circuit-breaker 5, 'the busbars 22 being fed from a transformer 23. Each control relay group has a manually operated switch 43 and the supply control bus-bars 22 with a switch 23<1>. If these switches are closed the following sequence of operations occurs :- The holding coil 15 of circuit-breaker 5 is closed and the motor relay 24 energized the motor 21 rotating the shaft 20 and so closing the circuitbreaker 5, the motor circuit being then broken. A time relay 46 is then energized which in turn energizes the relay 48 which completes its own maintaining circuit and switches in the feeder control bus-bars 56. The feeder circuit-breakers are then closed in succession by the angularlyspaced cams 9, the feeder holding coils 15 being all energized. If a short circuit now occurs in any feeder the overload relays 27 of that feeder and of the supply circuits operate energizing the control relays 28 which break the corresponding holding coil circuits 15. The consequent opening of the supply circuit breaker by producing de-energization of bus-bars 56 causes all the remaining feeder circuits to open and a reclosing operation as described above is then initiated. At each opening of a circuit-breaker the corresponding notching relay 39 is stepped round so that after a predetermined number of such openings the opening of contacts 33 prevent any further reclosure of this circuit-breaker. With moderate overload on any feeder the corresponding feeder circuit only is opened. In this case the circuit of the control relay 28 is maintained through the contacts of a time relay 57 which after a predetermined time interval opens its contacts deenergizing the relay 28 and allowing the automatic reclosure of the feeder-circuit breaker to take place. Specification 217,417 is referred to.