GB663334A - Improvements in electric contactor switches - Google Patents

Abstract

663,334. Air-blast switches. METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. July 11, 1950. [Sept. 12, 1949] No. 23531/49. Class 38 (v). A contactor suitable for use as a line switch in a traction or other motor control system, comprises an arc chute 3 associated with a blowout coil 4, and a nozzle 12 supplying a blast of pressure gas to the contacts 1,2, over a normallyclosed valve 14 which is opened in response to operation of an overload relay. As shown, contact 2 is operable by a coil 9 energised over the normally-closed contacts 18 of an overload relay 16 and contacts 25, 27 of a manual switch 24 ; the contactor may instead be operated by an electro-pneumatic motor. The valve 14 is controlled by a coil 15 in series with contacts 17 of the relay 16 and with contacts 28 which are open when contact 2 is fully open but are closed during the movement of contact 2 and when contact 2 is fully closed. On overload, coil 23 is energised, thereby releasing latch 21 to open contacts 18 and close 17, thereby releasing latch 21 to open contacts 18 and close 17, thereby opening contact 2 and energising coil 15. The contactor may be opened manually by moving contact 25 to the mid-"off"' position shown, the coil 15 in this case remaining deenergised as contacts 17 are open. The contactor is closed after overload by closing contacts 25, 26, thereby energising a coil 20 and reclosing contact 18 which is held by latch 21, 22, closure of contacts 25, 27 then energising coil 9.