THERMOSTATIC SWITCH OF ELECTRIC DEVICE Russian patent published in 1997 - IPC

FIELD: electrical engineering. SUBSTANCE: thermostatic switch is designed for protection of electric devices against overheating when fault emerges. It incorporates shell made from electric insulation heat-resistant material, two electrodes partially entering it, temperature-sensitive element in the form of tightly sealed tube produced from low melting-point conductive material which inner space is filled with substance-activator which does not conduct electric current. Shell has holes in points of entry of electrodes concentric on which two flexible electric insulation tubes are hermetically joined to shell to form elongated shell. Air gaps which ensure directional ejection of melt of temperature-sensitive element when thermostatic switch operates are formed between inner walls of elongated shell and electrodes. Elongated shell formed thanks to insertion of tubes can be manufactured in the form of one flexible tube. Length of elongated shell should meet certain condition to prevent drops of melt of temperature-sensitive element ejected from shell with operation of thermostatic switch from hitting metal parts of electric device and from formation with these drops of current-conductive short-circuit bridge with electrode of thermostatic switch. This condition provides for insulation of electrode up to at least first bends on size of temperature-sensitive element ensuring axial fixation of electrodes or up to terminal of electric device if electrodes are made straight. EFFECT: enhanced protection efficiency. 3 cl, 4 dwg