Abstract: The method of manufacturing metal oxide varistors wherein pressed blocks of selected mixtures of metal oxide powders and additives are joined to form a single varistor unit by vertically stacking and firing the blocks at a high temperature. Sintering of these stacked blocks during the firing cycle results in a strong mechanical and electrical bond between the adjacent blocks in the stack.

Abstract: A compact load break switch having at least one vacuum interrupter connected between two terminals carried by respective insulating bushings through a current exchange assembly. The vacuum interrupter is disposed within one of the insulating bushings, and a current exchange insulating housing having portions which extend telescopically into both insulating bushings, provides adequate creepage distance through air from the vacuum interrupter and the current exchange assembly to a grounded housing for the load break switch. Also, a current transformer is disposed about the insulating housing to provide remote indication of the flow of fault current through the current exchange assembly.

Abstract: An arrangement for the recessed mounting of an enclosed light fixture housing having an open end with a flange formed about the periphery thereof in an aperture defined in a planar member, such as a ceiling, includes a slotted aperture defined in the side wall of the housing with ratchet teeth formed therealong adjacent the slotted aperture, a support frame mounted behind the ceiling and including an aperture dimensioned similarily to and aligned with the aperture in the ceiling and a resilient mounting clip attached to the support frame and extending into the aperture. The free end of the mounting clip is dimensioned for receipt in the slotted aperture of the housing side wall upon insertion of the housing into the aligned ceiling and support frame apertures. Shoulder portions adjacent the free end of the clip engage the ratchet teeth to removably lock the housing in position in the ceiling.

Abstract: A manual operator for a series-connected circuit interrupter and disconnect combination mounted within a switch gearing closure, which includes an external operating handle affixed to a common operating shaft for the interrupter and the disconnect, which is rotatable about its axis between a closed position and an open position. A quick make, quick break, interrupter operating mechanism includes a manual operating shaft which is rotatable about its axis between a closed position and an open position. An operating rod has one end pivotally connected to a lever affixed to the common shaft and an opposite end pivotally connected to a lever affixed to the interrupter operator shaft, so that when the common shaft is rotated between its closed and open positions, the interrupter operating shaft is correspondingly rotated between its closed and open positions. The operating rod is held in a toggled position at both its closed and open positions by a spring connected between the rod and the switchgear enclosure.

Abstract: An electrical insulating coating of thermosetting polymeric material for a surge arrester valve element of silicon carbide particles bound together within a ceramic matrix, in which the coating is applied in powder form. Curing of the coating is effected either by a heating cycle following the application of the powder insulating coating, or by preheating of the valve element before application of the powder coating. Alternately, the insulating coating can be applied as a plasma spray, making post-curing unnecessary.

Abstract: A brazed slip joint is formed between housing portions, the portions forming an envelope to enclose an evacuated area. The ends of the housing portions overlap, one within the other, and each has a slight outward flare. The edge of the inner end makes line contact with the inner surface of the outer end. This arrangement defines an area between the overlapping ends which comes substantially to a point at that line contact and which is generally triangular in transverse cross section. That area is filled with a brazing alloy and a brazed joint is formed by exposure of the parts to the proper elevated temperature.

Abstract: A plate warmer having a heat storing core material for releasing heat to food serving supported thereon dishware over an extended period of time, i.e., in excess of thirty minutes, and a method of making said plate warmer. The heat storing material comprises beads of synthetic petroleum wax which are compressed to form a solid core having inwardly concave top and bottom surfaces and to expel air from the core. Top and bottom outer plate members are compressed to conform to the inwardly concave surfaces of the core and then sealed to define an airtight, waterproof cavity which is filled by the core. When the plate warmer is heated, the core expands outwardly against the concave walls of the outer plate members and the walls assume a substantially flat configuration wherein the cavity is enlarged to accommodate the expanded core material, the walls reassuming their inwardly concave configuration as the heat storing core material cools and releases heat through the top outer plate member to the dishware.

Abstract: An electric skillet or the like cooking vessel includes a cooking pan and a removably attachable insulative handle having a temperature control assembly with a spring loaded temperature sensing "shoe". One portion of the side wall of the pan defines a raised temperature sensing area against which the "shoe" is pressed upon joining the pan and handle. A lip extends from the raised area and forms a recess between the lip and sidewall of the pan. A first end of a torsion spring mounted on the handle for rotation is received in the recess for engagement with the lip subsequent to joining the handle and pan and rotating the spring to a first, locked position. The opposite end of the spring is received beneath a shoulder provided on the handle, thereby twisting the torsion spring to cause the first end thereof to forcibly engage the lip.

Abstract: A switchgear assembly which includes a vacuum interrupter, a current transformer, and a capacitive voltage sensor, all embedded within a cast epoxy housing mounted to a solidly grounded support structure. The voltage sensor includes a first capacitor, which is formed by an interrupter conductor stud, a plate, and the cast epoxy disposed therebetween, and a second capacitor, which is connected between the plate and a metal tube extending outside the housing. The tube is connected to ground through a conductive coating, applied to the housing, having an impedance which is very low in comparison to the impedance of the first capacitor.

Abstract: A unique core for an electrical transformer and method of construction thereof is disclosed which is applicable to either shell-form or core-form transformers of either single-phase or multi-phase application. The cross sectional area of the outside core leg and a portion of the yoke outside the electrical coil of the transformer is increased thereby decreasing the magnetic induction of that portion of the core with a concomitant reduction in electrical losses and noise. The structure comprises leg and yoke stacks formed of lamina of grain-oriented steel that are stacked in a laminar relationship such that adjoining edges of the leg and yoke members are periodically overlapped to enhance flux transfer. The core is stacked in such a fashion such that the outside leg members (outside the electrical coil) have additional laminar members periodically interspersed so that there are more outside leg lamina than inside leg lamina thereby increasing the cross-sectional area of the outside legs.

Abstract: A protective device for electrical power distribution equipment includes a removable fuse holder and an integral load switch. The protective device may be affixed to a grounded metal enclosure, such as an oil-filled transformer, into which the protective device extends. The fuse holder may be removed from the protective device for checking or replacement with a minimal opening into the enclosure into which the protective device extends. A suitable load switch actuator is provided for controlling current flow through a fuse in the fuse holder. This load switch actuator also provides an interlock arrangement to prevent removal of the fuse holder from, as well as insertion of the fuse holder into, the protective device unless the load switch is open, thus ensuring that interruption and initation of current flow through the fuse in the removable fuse holder is controlled by the load switch.

Abstract: An apparatus for processing an electrical apparatus, such as a capacitor, containing a polymeric dielectric material. The interior of the capacitor casing, which is at room temperature, is initially connected to a vacuum source to evacuate the interior of the casing and when a vacuum sensing unit indicates that the required vacuum has been obtained, a degassed dielectric liquid is supplied to the interior of the casing. A positive pressure is applied to the liquid in the casing to fully impregnate the polymeric layer. When the desired capacitance is obtained, the impregnation is complete and the unit is sealed.

Abstract: An evaporative cooler having a one-piece, frameless shell secured to a bottom pan and having a top cover hinged along one edge to the side wall of the housing shell. A quick-release latching mechanism secures the top cover to the opposite side wall to hold the top cover closed while permitting the top cover to be easily opened for access to components of the evaporative cooler housed therein. Evaporative media pad assemblies have side frame members having V-shaped outer surfaces which slide in correspondingly shaped tracks in the corners of the shell to space the pad assemblies from the louvered side walls of the shell and permit the pad assemblies to be installed and removed from above with a vertical sliding movement.

Abstract: An adjustable light fixture recessible in a ceiling for directing light at various angles includes a housing with a lamp assembly mounted therein. The lamp assembly comprises a reflector having a conventional bulb socket attached pivotally to a plate having spaced apertures. Resilient tracks, mounted at one end to the base of the housing are received in the apertures provided in the plate, rendering the plate slidable along such tracks. The tracks are each provided with a series of protrusions engagable with rollers each of which are mounted on the plate adjacent the spaced apertures to form a series of overcenter arrangements whereby the position of the plate and the lamp assembly may be adjusted. Stops are provided at the free end of each track to limit the movement of the lamp assembly therealong. However, the stops may be bypassed to permit complete removal of the lamp assembly from the housing.

Abstract: A lighting unit comprising a lamp and a reflector provides high intensity, high efficiency, even illumination over an area of particular shape and size and has a cut-off angle which enables a person to approach close to the lighting unit without seeing the lamp or its reflection. The reflector comprises at least two spaced apart curved reflector surfaces which join each other along an edge line in a plane behind and spaced from the lamp. Points on the curve line of each reflector surface are spaced progressively further away from the lamp than the edge line. Some points on the curve are located on the side of the plane remote from the lamp. The lighting unit, which may employ reflector surfaces in addition to those above mentioned, may be employed in systems wherein it projects light upwardly for downward reflection from a ceiling or projects light downwardly directly onto a work surface.

Abstract: Apparatus for continuously lubricating a conveyor belt with a mixture of water and soap or detergent during normal operation and for washing the conveyor belt during a preselected time interval after normal operation has ceased. Solenoid valves are interposed in water lines to a lubricating nozzle and wash nozzles to control the flow of water to the nozzles, and pumps are provided to inject soap or detergent into each of the water lines. During normal conveyor operation, electrical power is supplied only to the lubricating line solenoid valve and the lubricating line pump to produce a lubricating spray of water and soap or detergent from the lubricating nozzle which is directed onto the belt. When the master on-off switch is switched to the "off" position, a wash timer is actuated for a predetermined interval of time and cooperates with a relay to also enable the wash line solenoid valve and the wash line pump to deliver water and soap or detergent to the wash nozzle for cleansing the conveyor belt.