Patent GB-227473-A (GB)
Title: Improvements in and relating to electric circuit controlling devices
IPC: H02H3/07
Filed: 1925-01-12
Abstract: 227,473. British Thomson-Houston Co., Ltd., (Assignees of Traver, O. C.). Jan. 12, 1924, [Convention date]. Protective arrangements ; switches, actuating ; latching ; make-and-break switches, mechanical ; timing-devices. - In a circuit-breaker having relatively movable co-operating contacts provided with a plurality of spaced power-operated actuating members movable simultaneously in one direction to actuate the contacts successively, means are provided for controlling the movement of the members comprising an electromagnet and an armature which, in its normal position, holds the members in an inoperative position, and in another allows the power to move the members to actuate the contacts at intervals dependent on the spacing of the members. The contacts 1, 2 are actuated by the members 3, 4, 5 driven by a motor 6 through gearing and controlled by a magnet 7 with an armature 8. The members are adjustably mounted on a shaft 9 carrying a graduated gear 10 and a stop 16 engaging the armature 8 which is biassed by a spring 15 and, on being attracted, frees the stop and allows the motor 6, which is preferably continuously driven at constant speed, to rotate the shaft 9. The contacts 1, 2 are mounted on pivots 17, 18 and arranged to close with a hammer blow, this being effected by giving the free end of contact 1 a lost motion and by supporting it on a rest 19 which carries a flange 20 supporting the contact 2. When one of the members 3 .. 5 engages the contacts, it first lifts them, then releases contact 1 and moves contact 2 against contact 1 which is falling to it. The armature 8 has a stop 21 engageable by an adjustable stop 22 on the shaft 9 so as to allow almost one revolution of the shaft after the stop 16 has been released. The motor 6, shown as of the, induction disc, shaded-pole type, is mounted on a shaft 27 having a bearing in a shaft 31 to which it is connected by a spring clutch 28, adjustable by engaging the teeth of the pinion 29. The circuitbreaker 32 controlling the line 33 is closed by a coil 36 energized from auxiliary bus 37 which also energizes the magnet 7, the motor 6, and the manually operated trip coil 39. When abnormal conditions open the breaker, the switch 40 energizes the magnet, 7, which attracts its armature 8, releases the stop 16, and allows the members 3 .. 5 to rotate. After a relatively short interval the contacts 1, 2 are closed by member 3 and the coil 36 closes the breaker and de-energizes the magnet 7. However, the shaft 9 will make a complete revolution until the stop 16 engages the armature to arrest it. If the conditions are such that the breaker opens after the member 3 has closed it, then the member 4 during the same revolution closes it; and if it again opens, the member 5 closes it; if it again opens, the armature 8, being attracted, at the end of the revolution engages the stop 22 and the device is locked against further operation, since the flange 23 of the part 21 prevents return of the armature. To free the stop 22, the switch 41 is opened to de-energize the magnet 7, and gear 10 and shaft 9 are moved back a small distance by means of a lever 25 engaging a lug 24 and the stop 22 then clears the flange 23. The number of members 3 .. 5 and the interval between them may be varied, but preferably the latter are fixed so as to be progressively increasing.