Abstract: A thermal protective device for interrupting current to the lamp circuit of an electrical lighting fixture when the temperature at a preselected location in the fixture reaches a predetermined level, comprises a receptacle including a pair of female terminals coupled electrically to the lamp circuit. A normally open switch having a movable contact arm with a hooked end portion is coupled to one of the terminals to maintain the lamp circuit normally open. A plug adapted for joinder with the receptacle includes a pair of male terminals arranged for receipt by the female terminals of the receptacle. A thermal protector included in the plug is operable from a closed to an open condition when the temperature reaches the aforesaid predetermined level. The thermal protector is connected electrically across the male terminals. An actuator and latch arm extending from the plug is received in the receptacle upon joinder of the receptacle and plug.

Abstract: A current limiting fuse construction including a fuse element extending between electrically conductive terminals carries a body of arc-quenching filler material within a hollow casing of electrical insulating material. The filler material includes a first portion of arc quenching aluminum sulfate mixed with calcium sulfate binder, and second portion of arc quenching silica sand arranged in stratified layers, with the aluminum sulfate layer being positioned closest to a weak spot of the fuse element, and the layer of silica sand being positioned closer to an end cap of the fuse casing.

Abstract: A recrystallized copper billet in excess of one and one-half inches in diameter is formed as an essentially single-grain or crystal copper. A high conductivity, oxygen-free copper billet is subjected to mechanical surface cleaning and to a "bright dip" bath to chemically clean the surface. The copper billet is located in a similar sized graphite crucible and induction-heated in a vacuum chamber to a modest temperature for outgassing of said crucible. The heating is increased to melt the copper and then is reduced in steps to produce a copper equilibrium temperature about seventeen degrees centigrade above the melting point of the copper. A slow non-directional and natural cooling at the rate of about three to fifteen degrees per hour is created until total solidification and recrystallization occurs.

Abstract: A rolling conductor support for supporting, guiding, and protecting electrical, hydraulic, coolant and the like conductors extending between parts of machines which move relative to one another on guides or tracks. The conductor support comprises a plurality of chains connected in parallel, laterally spaced relation by conductor supporting bridges to which the conductors are fastened by releasable securements. The chains are comprised of a series of alternating and overlapping follower links and control links, overlapping portions of which are pivotally connected to each other. Six holes are formed in each follower link, one at the center of each end for making a pivotal connection to the overlapping control link. The remaining four holes, having stop pins secured therein, are positioned in pairs at each end of the link adjacent the pivotal connection.

Abstract: A conductive bushing connector includes an elongated metal stud having a center axial passage, a plurality of transverse apertures, and threaded portions at each end. A pair of insulative housings assembled on opposite sides of a transformer enclosure each overlying the metal stud and abutting the wall of the transformer enclosure form a cavity surrounding the metal stud. A pair of threaded end terminals cooperate with the threaded end portions of the metal stud to secure the entire assembly. Each interface of the assembly is provided with resilient sealing members which are maintained in compression by the end terminals. The insulative housing within the transformer enclosure includes a plurality of fluid convection apertures.

Abstract: A pan for a ceiling mounted light fixture includes a saucer-like canopy defining a mounting hole for receipt of a fastener to secure the light fixture to a ceiling support surface. A first layer of insulative material is received between the canopy and the ceiling surface. Descending arms spaced about the periphery of the canopy join the canopy to a housing portion which is suspended therefrom. The housing portion includes concentric outer and inner walls, the latter of which has an inwardly extending lip or ledge defining a shelf to support a second layer of insulative material disposed between the canopy and shelf. Electrical sockets for receiving incandescent lamps are mounted on the lower wall of the shelf and a glass or the like shade is received thereover and secured by screws extending through the outer wall of the housing portion. The double layers of insulative material serve as barriers to prevent damage to the ceiling surface from heat generated by the incandescent lamps of the light fixture.

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: An arrangement for mounting an enclosed light fixture housing having an open end with a flange formed about the periphery thereof, in recessed fashion in an aperture defined in a planar support member having inner and outer surfaces, with the flange of the housing engaging the outer surface, includes a side wall of the housing defining a T-shaped slotted aperture with the longer leg of the T extending from the shorter leg toward the open end of the housing, and having ratchet teeth formed along an edge of the longer leg of the T, and a mounting clip receivable in the slotted aperture from the interior of the housing after the housing is received in the aperture in the support member. The mounting clip is captured in the slotted aperture and slidable toward and away from the inner surface of the support member.

Abstract: A variable speed induction motor control system includes a variable voltage DC bridge coupled to a frequency controlled power inverter which in turn drives an induction motor. A motor power factor detecting circuit determines the relative voltage/current phase angle for the motor and derives a corresponding power factor error signal. The DC bridge and inverter respond to the power factor error signal to maintain the input power conditions of the motor at a near optimum efficiency. The power factor detecting circuit uses an exclusive OR gate to provide a pulse having a duration corresponding to the motor power factor which enables a counter during the pulse interval. After each pulse, the count which is indicative of the motor power factor, is applied to a holding circuit and converted to an analog error voltage.

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: A flexible connector assembly for coupling, both mechanically and electrically, sections of electrical distribution track in a track lighting system includes first and second connector segments each having at a first end, a plug-in type tapping mechanism for joining the segments mechanically and electrically to sections of electrical distribution track. A flexible and expandible member formed of a pair of conductive, coiled, wire elements concentrically wrapped in opposite directions with respect to each other, is joined at opposite ends at the second ends, respectively, of the connector segments. The coiled wire elements define a tubular passageway for electrical conductors coupling the connector segments electrically and the member itself provides a ground connection between the connector segments and corresponding track sections.