GB425748A - Improvements in and relating to automatic circuit breakers enclosed in a casing - Google Patents

Abstract

425,748. Automatic circuit-breakers. FELTEN & GUILLEAUME CARLSWERK AKT.-GES., M³lheim, Cologne, Germany. Aug. 28, 1934, No. 24741. Convention date, Sept. 4, 1933. [Class 38 (v)] A casing 1 for an automatic circuitbreaker is provided with a box-like insertion 2 of insulating material forming a completely closed switching chamber, the lower part of the casing being provided with a chamber 5, open at the rear, for the introduction of the leads 6. The switching chamber is divided by partitions into a number of compartments corresponding to the number of phases, and an insulating plate 23 may be provided between the insertion 2 and the cover 22 of the casing. The fixed contacts 7 are U-shaped and serve as exciting windings for blow-out magnets 11. The fixed contacts are provided with integral projections 8 which pass through the wall of the insertion 2 into the front connecting chamber and serve as terminals. The connecting leads 6 are sealed by a rubber plate 20 held in place by a pressure plate 21. The movable contacts 12 are connected to supporting members 14 which pass to the front of the insertion 2 and are secured by the fixing screws of bimetallic strips 17 which serve as overload releases, the other ends of the strips being connected to terminals 18. The supporting members 14 are connected to the shaft 26 by links 24, 25, and an arm 38 on the shaft 26 is connected by toggle links 37, 36 to a lever 39 on a shaft carrying an operating handle. The switch may be used for protection against insulation failure in domestic appliances such as electric fires or irons, and is provided with a fault release coil 28 connected at one end to earth and at the other end, through a protecting conductor, to the casing of the appliance. If current flows through the coil 28, its armature 29 is attracted and upsets a pair of toggle links 31, 32, thereby releasing the spring- controlled toggle links 34, 35 which in turn breaks the toggle 36, 37 and releases the switch. The armature can also be moved to release the switch on overload by an arm 40 on a shaft 27 controlled by the bimetallic strip 17. The switch may be provided with a testing device comprising a pair of levers 43, 44, the lever 43 being connected to the coil 28 and normally making contact with the protecting conductor. By operating a key 48 the lever 43 can be separated from the protecting conductor and connected, through a resistance 45, to the lever 44 which can be moved from a contact 46 connected to one phase to a contact 47 connected to another phase.