GB387037A - An improved electrical cut-out - Google Patents

Abstract

387,037. Automatic circuit-breakers. BARNETT, A., 3, Hillfield Avenue, Hendon, London. Sept. 26, 1931, No. 26910. [Class 38 (v).] An automatic cut-out which is adapted to open a circuit such as a battery circuit when any temporary diminution of current occurs therein due, for example, to a loose connection, has a single winding 2 in series with the battery, this winding normally holding a hand-set armature 13 in the attracted position in which a bridging member 14 dips into mercury cups 18. Adjustment for release at a predetermined minimum current is effected by an adjustable core member 9 the polepiece of which is arranged to be separated from the armature by a suitable air gap so that when the current falls below the predetermined value the spring 21 overcomes the magnetic attraction of the armature and breaks the circuit at the mercury cups 18. The method of adjustment of the core 9 is shown in Fig. 3, the core being urged upwardly within a sleeve 4 by a spring 11, the threaded lower end of a depending portion 10 of the core carrying an adjustment nut 12. The core is prevented from rotating during adjustment by a screw 141 engaging a recess 15 in the core. The armature is reset after release by a spring- returned manually-operated plunger 25 bearing on the upper side of the armature 13. This plunger acts as a contact when the armature is released and engages it, so closing an alarm circuit including a bell 28.