PROBLEM TO BE SOLVED: To secure stable curvature operating characteristic, to reduce consumed power and to reduce heat interference between phases by uniformly winding heater wire to bimetal without any deviation in winding pitch by applying a simple processing to the bimetal.;SOLUTION: A heat element corresponds to each phase of the main circuit of a thermal relay which is linked to each contact point mechanism through a shifter. The heat element 2 consists of the bimetal 6 with an operating end confronting the shifter and connected to the main circuit by having another end fixed to a terminal 10, and the heater wire 8 which is serially connected with the bimetal by being wound around the periphery surface of the bimetal. Indented grooves 6b for alignment retaining the heater wire 8 to a specified winding position are formed on the right and left side edges of the bimetal according to the winding pitch p of the heater wire. Furthermore, the periphery surfaces of the bimetal and the heater wire are covered by a heat resistant thermal insulator 11 in an assembled state with the heater wire wound to the bimetal.;COPYRIGHT: (C)2006,JPO&NCIPI
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