GB1391919A - Drive for electric circuit-breakers - Google Patents

Abstract

1391919 Actuation of switches B B C BROWN BOVERI & CO Ltd 21 Sept 1972 [23 Sept 1971] 43763/72 Heading H1N A mechanical drive for a circuit breaker has, as shown in Fig. 1, an operating rod 14b attached to a piston 14 which is moved in alternate directions in a cylinder 14a by gas pressure generated from the detonation of cartridges 11 accommodated in stationary magazines formed by bores in end flanges 10 each flange carrying a spring-driven rotatable part 22 having a striking lever 9 together with a gas-pressure controlled locking device (spring catch 18 and grooves 21) which governs the presentation of a fresh cartridge after each detonation. The striking mechanism comprises an annular armature 8 with associated push rods 8a which is normally held in a restrained position by a permanent magnet 7 against the action of a spring 24 (R.H.S. of Fig. 1) and is released by momentarily weakening the magnet field by energizing an electrical control coil 26. When so released the armature moves against the striking lever 9 (L.H.S. of Fig. 1) carried on an arm 22a and one of the cartridges in the magazine is detonated. Apart from the shaping of the chamber 5 or 6 defined by the end flange 10 and the open end of the cylinder 14a the arrangement at each end of the cylinder is identical and the pressurized gas produced by the detonation is introduced both for the main drive and for auxiliary functions by means of various ducts which serve as communicating passages within the flange and the rotatable part. Immediately the gas pressure builds up in the chamber 5 (or 6) the piston 14 starts to move the operating rod 14b and the push rods 8a are actuated via duct 15 to restore armature 8 to its magnetically attracted position, but when the piston uncovers vents 19 the gas pressure on its driving side falls and permits spring 20 to move parts 17, 17a against the lowered pressure in duct 16 to release spring- loaded catch 18 following which part 22 is moved by spiral spring 23 to rotate one step as determined by grooves 21 (Fig. 3a) and restoration of catch 18 by its own spring, thus presenting a fresh magazine cartridge position. The storage facilities of the magazines may be increased by using staggered bores 1 and 2 and a modified striking lever 91 as shown in Figs. 2 and 3. Chambers 5 and 6 may have different volumes so that, with identical cartridges, the driving energy imparted to the piston 14 may be different in the alternate directions.