GB1284094A - A circuit breaker with an automatically resettable trip device - Google Patents

Abstract

1284094 Automatic circuit breakers HEINEMANN ELECTRIC CO 28 Oct 1969 [15 Jan 1969] 52726/69 Heading H1N An automatic circuit breaker of the kind having a manually operable linkage 20 for opening and closing the contacts 30, 32 and having a lock 57 releasable by an electromagnet 41 to open the contacts automatically is adapted for no-volt release. The electromagnet comprises a coil 40 and frame 52 with a non-magnetic tube 65. The tube contains a freely movable magnetic core 66 spring urged downwards. The core 66 carries an extension 80 with a large head 87 co-operating with a pivoted member 84 corresponding to the usual tripping armature. When the core is normally energized the core 66 is drawn upwards into engagement with an insulating buffer 76 (which prevents sticking of the core). If the energization of the coil falls below a predetermined value the core 66 moves downwards and member 84 is pivoted to release the lock 57 on the toggle linkage allowing the contacts to open. The handle is returned automatically to the off position resetting the toggle linkage. A magnetic shunt 94 is fitted and a gap 97 is present in the released position of core 66 so that the member 84 is not held by the electromagnet. A two pole circuit breaker (Fig. 8, not shown) has one pole constructed as above described and a second pole responsive to overload in which the member 84 is replaced by an armature (134) and the core 66 by a slow moving magnetic slug providing delayed tripping. Each pole has an arm (120) (Fig. 7, not shown) pivoted on the pivot of the member 84 or armature (134) and which is turned by the opening of the respective contacts. The two arms are coupled by a shaft (202) and act upon their respective members 84, (134) so that both poles are tripped by either overload or undervoltage.