Abstract: A thermal switch comprises an elongate tubular sealed housing. A control circuit is mounted in the housing. The control circuit comprises a thermostat, a fuse and a thermal overload switch electrically connected in series. An electrical connector is mounted to the housing and is connected to the control circuit.

Abstract: A cartridge heater assembly to be swaged has a sheath with head and slug ends. A resistance heater unit in the sheath includes a flat rectangular core, a resistance wire winding on the core, and first and second core covers, one on each side. Each end of the resistance wire extends from the core through a hole in the adjacent core cover and to the head end of the sheath. Crushable heater unit centralizers at each end of the sheath hold the resistance heater unit. Leads are connected to the ends of the heater wire and the connections are enclosed in the centralizer. A plastic bushing closes the head end of the sheath and a slug closes the slug end of the sheath. The heater assembly is filled with an insulating material and swaged, crushing the centralizers.

Abstract: An electrical cartridge heater includes a flat rectangular core of mica. A resistance wire is helically wound around the mica core. A cover sheet of mica is placed on one face of the wound core so that a return wire extends back without shorting against the other wires. The mica core is received in recesses in head and slug end bushings to position the element centrally within a cylindrical shell. A granular fill surrounds the core and heating element within the shell.

Abstract: An electric heater for heating oil contained in the sump well of a compressor includes a thermally conductive shell having first and second opposed inner surfaces. A ceramic core having a D-shaped cross-section throughout is positioned in the shell and is provided with longitudinal channels which are disposed substantially the same distance from the outer curved surface of core. An electric resistance heating element is disposed in the channels and is energizable by a source of power for developing heat under the control of a thermostat disposed in the shell. A resilient pad of ceramic fiberglass material having low thermal conductivity is disposed between the flat surface of the core and the thermostat and urges the curved surface of the core and the thermostat into contact with the opposed inner surfaces of the shell while substantially blocking heat transfer therethrough from the heating element to the thermostat.

Abstract: A heater band formed of an extruded metal channel member and a heater plate assembly received within a slot extending along the length of the channel. The heater plate assembly and the extrusion are compressed together to provide a heater band having a dense cross section resulting in improved heat transfer characteristics. The heater band in accordance with the present invention has a longer life and higher heating capabilities than heater bands known to the prior art.

Abstract: A heater band formed of an extruded metal channel member and a heater plate assembly received within a slot extending along the length of the channel. The heater plate assembly and the extrusion are compressed together to provide a heater band having a dense cross section resulting in improved heat transfer characteristics. The heater band in accordance with the present invention has a longer life and higher heating capabilities than heater bands known to the prior art.