| 摘要 |
<p>707,262. Thermal switches. METROPOLITAN VICKERS ELECTRICAL CO., Ltd. Nov. 6, 1952 [Dec. 17, 1951], No. 29491/51. Class 38(5) [Also in Group XXXV] Relates to a protective device for electromagnetic apparatus, such as an electric motor, in which contacts are actuated in response to heat received from a part of the apparatus so as to provide tripping or alarm operation. A dished bimetallic disc 1 is in thermal relation with a sheet metal member having an annular central portion 3, and wings 4, 5, which may readily be bent to conform with the relevant surface of the protected coil or the like. The sheet metal member may, for example, be held in contact with the surface of the coil by means of tapes. A contact pin carried on a spring blade normally engages a contact at the centre of the bimetallic disc 1, but, when the temperature of the protected coil reaches a given value, which is varied by screw-adjustment of the position of the spring blade, the bimetallic disc will snap overcentre into engagement with a back-stop, so opening the protective circuit.</p> |
