Abstract: An improved annular resistor, suitable for use in a diesel electric locomotive dynamic braking system and similar applications comprising an assembly of similar arcuate segments. Each resistor segment has a supporting frame (11, 13) and a continuous resistance ribbon (53, 55, 57, 59) having a plurality of reflexed radial extensions between the two parts of the frame, electrically isolated from the frame. To allow expansion and contraction of the ribbon, U-shaped folds of the ribbon are mounted on pin supports (51). The pin supports are mounted to insulator blocks (27, 29, 37, 39), and are set so as to position the ribbons in a zig-zag or chevron pattern, in order to enhance cooling and improve the flow of air over the ribbon surfaces. Three terminals (67, 73, 75) are provided on each segment to allow part of the resistance of each segment to be removed from the circuit.

Abstract: A heat transfer arrangement for zinc oxide varistors comprises a metal heat sink disk held in contact with one face of the varistor by means of a circumferential elastic sleeve. The heat generated within the varistor rapidly conducts into and is absorbed by the metal disk and transmits through the elastic sleeve to the environment. When the varistor heat sink assembly is mounted within a surge voltage arrester, a flexible positioning member holds the assembly tightly against the arrester housing for transferring the heat to the housing.

Abstract: An improved electrical heater using a vacuum surrounding the heating element instead of the usual gaseous or liquid medium for transfer of the heat to external means of dissipation. The heating element, enclosed and sealed in a surrounding encasement which has been evacuated after being sealed, transmits its heat across the vacuum by radiation to the encasement and thence to a series of fins as the means of external dissipation. The heater thereby improves the efficiency of the utilization of the electrical energy used to supply the heat source. The heat dissipating fins are provided with integral spacer lips and are secured on the surrounding encasement by end plates which are formed with downwardly extending portions forming feet on which to stand the heater.

Abstract: An electric heater, particularly adapted for supplying heat to hazardous areas where the atmosphere in the area contains particles or fumes that are readily ignited. The heater includes one or more heat radiating members, each cast about a sheathed electric heating element. The terminal ends of the heating element extend into a sealed explosion-proof terminal box. The heat radiating members are serially disposed in a tubular casing, and a motor-operated fan blows air through the casing and over the members, the air being heated as it flows over the heat radiating members.Each member is in the form of an annular hub having integral, heat-dissipating fins extending radially thereof. The outer surface of the hub is formed with a contour that is angled or curved in the direction of the air flow, and such contour is constructed and arranged to provide a Venturi effect to draw air from the inner portion of the hub to the outer periphery and thus prevent build-up of excessive heat at the inner portion.

Abstract: The present device is a high reliability resistor comprising a sheet of metal foil secured to the flat side of a substrate and with the opposite side of the substrate formed to dissipate heat into the ambient thus enabling the present resistor to have an improved temperature coefficient of resistance (TCR) and further enabling the resistor to function satisfactorily in a high wattage mode.

Abstract: An annular resistor, suitable for use in a diesel electric locomotive dynamic braking system and the like, having a supporting frame including spaced inner and outer annular frame portions and a continuous resistance ribbon having a plurality of bent-back radial extensions therebetween and in electrical isolation therefrom. U-shaped folds of the ribbon are mounted on pin supports allowing contraction and expansion of the ribbon. The pin supports are mounted to insulator blocks which may be selectively positioned on the frame, when two or more are stacked, to vary ribbon alignment and hence convective cooling. The resistor is comprised of severally replaceable identical component quadrants.

Abstract: The invention is a temperature sensing wire resistance probe including a temperature responsive resistance element assembled in a novel method and having insulation adequate for direct connection in the line voltage circuit of an oven temperature control.

Abstract: A thick film spiral shaped resistor deposited on an alumina substrate and bonded to a Kovar plate, an aluminum heat sink is coated on one side with a silicon grease and the Kovar plate is bolted thereto.