GB567019A - Improvements in and relating to thermally responsive electric protective devices - Google Patents

Abstract

567,019. Temperature-responsive actuating-elements. BRITISH THOMSONHOUSTON CO., Ltd. July 21, 1943, No. 11868. Convention date, July 21, 1942. [Class 64 (ii)] [Also. in Groups XXII and XXXVII] A thermal overload protective device suitable for fractional horse-power, single or polyphase motors, comprises an expanding-liquid container having a tubular part adapted to be inserted between the stator end turns and into the windings in one of the slots, Fig. 1 (not shown). The tubular part 14 is expanded at the open end 20 and crimped or spun over the rim of an aperture in a disc-like member 19 which is also soldered to the tube at 21. The grooved rim 22 of disc 19 is compressed on to, and soldered to, a snapping disc 18 so as to form a closed container which is filled with proptyl alcohol while heated to nearly its boiling point. The disc 18 operates contact 17 through member 23 so as to open the switch on attainment of a given winding temperature and permit its reclosure when the winding cools. The container is secured in a stepped recess 30 in base 24 by an apertured bar 34 cemented in place, a cover 31 being secured to the base by U-shaped wire clip 32 which passes through apertures in the cover and base and has its ends bent over the rim 22 of disc 19.