Motor protector with metal housing and with preformed external heater

Abstract

A motor protector has a thermally responsive contact element mounted inside a flat, rectangular, open-ended metal can. A metal cover mounts a complementary contact and is secured over the open end of the can by can flanges to clamp an electrically insulating gasket between the can and cover. The contact means close a circuit between the can and cover but the thermally responsive contact element is movable in response to increase in temperature for opening that circuit. Integral crimpable terminals are provided on the can and cover. A flat metal heater ribbon having an insulating coating thereon has one end welded to the exterior of the can. The ribbon coating is deformed at selected locations and the coated ribbon is folded at those locations to fit closely against the three exterior sides of the flat rectangular can. The can terminal crimps the opposite end of the coated ribbon in electrically insulated relation to the ribbon for holding the coated ribbon in position on the can. In that way, the heater is adapted for automated assembly on the can to provide consistent uniform heat-transfer to the can. The heater is also disposed to be easily and reliably connected in series with the contact means in a motor circuit for improving the thermal response, cost and service life characteristics of the motor protector.