GB548444A - Improvements in and relating to gas blast electric circuit breakers - Google Patents

Abstract

548,444. Valves. BRITISH THOMSONHOUSTON CO., Ltd. July 17, 1941, No. 9050. Convention date, July 17, 1940. [Class 135] [Also in Group XXXVII] A gas-blast switch having a container for supplying adequate blast when the switch is opened on abnormal current conditions, has means for reducing the blast supplied when the switch is opened on normal current conditions. The blast may also be supplied during closure. The invention is shown as applied to a switch with an arc-chute 13 and horizontally-slidable movable contact 12, as set out in Specification 544,017, [Group XXXVII], operation being pneumatically effected from the container 27 by a rotatable shaft 22 and fluid-motor 18, 19, as in Specification 541,165, [Group XXXVII], for example. A current transformer 42 in the line to terminal 15, on operation, causes winding 41 to close contacts 43, so energizing the opening winding 33 of operating valve 28 and winding 38 of valve 35 which admits 'full blast to the arcchute. For manual operation, a button 45 closes contacts 46 to energize winding 33, 38 and contacts 47 to energize a winding 40 and deflect a pivoted flap 54 normally aligned with pipe 16. In Fig. 2, the blast-reduction is effected by obstructing the full movement of valve 35 by the stop 48 controlled by the manually-controlled winding 49. In Fig. 3 (not shown), valve 35 is shunted by a valve of smaller size, the two valves having separate operating windings.