Abstract: A pressure measuring system which includes a variable reluctance pressure transducer energized from an alternating voltage source, wherein the ratio of the output voltage to the source voltage is proportional to the pressure being sensed. Precision full wave rectifiers convert the source and output voltages to reference and sensing direct voltage signals, respectively. A switching regulator regulates the higher amplitude reference voltage signal to have exactly the same average voltage as the sensing voltage signal. The switching regulator also regulates a constant voltage DC signal from a regulated power supply at the same switching duty cycle as the regulated reference voltage signal, to produce a direct voltage, pressure-sensing signal which is uneffected by voltage fluctuations in the alternating voltage source for the pressure transducer.

Abstract: A weather-proof light fixture includes a quick connect modular ballast assembly which is separably connected to a light reflector member mounted on a support surface. A housing containing the ballast assembly has a lamp receptacle extending from a sidewall thereof. The light reflector member includes a neck portion the end of which is butted against the housing, receiving the lamp receptable therein. Outwardly projecting fastener arms extending from the neck portion each having a hollow cavity therein are rotated over posts protruding from the ballast housing sidewall, and located adjacent the lamp receptacle. Slots contained within the fastener arms receive screw fasteners extending from the posts to secure the lamp ballast housing and reflector member in a joined condition. A gasket disposed between the end of the neck portion and housing side wall, renders the light fixture waterproof.

Abstract: The minimum instantaneous voltage output of a phase resistor connected to receive the rectified phase and neutral currents of three wye-connected current transformers, magnetically coupled to respective phase conductors of a three phase electric power circuit, is proportional to the peak current of the phase conductor carrying the center magnitude phase current. A voltage proportional to this minimum instantaneous voltage is measured and stored by a capacitor each cycle. The peak instantaneous voltage output of a ground resistor connected to receive the full wave rectified output of three, parallel-connected current transformers, also coupled to respective phase conductors of the power circuit, is proportional to the peak ground current of the electric power circuit.

Abstract: A switch of the type utilized for machine tool controls and actuated by a roller passing over a cam track has two members mounted for independent reciprocation along a plunger actuated from the cam track. One of the members carries a movable contact or contacts, while the second member is utilized to trigger the first member. Each of the members is independently activated by an associated overcenter arrangement for snap action. A compression spring is utilized to return drive the plunger from the position to which it is moved by the action of the roller on the cam track. Movement of the plunger under the driving force of either the roller and cam track or the compression spring provides for a snap action of both members in the appropriate direction upon activation by their respective overcenter arrangement.

Abstract: A drawout switchgear assembly which can be disconnected from a shielded cable electric distribution system under energized cable conditions. Each of the switchgear source and load bushings is held within a stationary cable connector with sufficient pressure exerted by the switchgear drawout operating mechanism to maintain a waterproof, fully shielded connection. Each stationary cable connector includes a current exchange bayonet member carrying a louvered band having resilient contact fingers which engage the movable switchgear bushing rod within a cavity of this rod for receiving the bayonet member. A switchgear drawout operating mechanism includes a mechanical interlock which allows withdrawal or reconnection of the switchgear only when the switchgear is in its open position.

Abstract: An inrush current restraint circuit, for use with a typical overcurrent minimum pickup circuit of a power system switching device, such as a recloser or sectionalizer, for raising the initial overcurrent minimum pickup value upon closure of the switching device to a selected value, then linearly returning this pickup value to normal within a selected period of time. The minimum pickup circuit is actuated by the voltage drop across a current sensing resistor, through which a current signal proportional to current in the power system is passed. The initial pickup overcurrent value is increased by providing another current path in parallel with the current sensing resistor when the switching device is closed. A timing capacitor is discharged each time the switching device is open, then charged from a constant current source each time the switching device is closed.

Abstract: A full-range, current limiting fuse which includes a modular fuse subassembly which can be assembled with any pair of several types of paired end caps to construct any one of several types of fuses. This modular subassembly includes a main fuse element helically wound about a gas evolving spider and connected to element termination plates mechanically attached to each end of the spider, and an auxiliary fuse element, electrically isolated from the main element, which is also helically wound about the spider and connected at one end to a contact button centrally disposed at one end of the spider.This modular subassembly is positioned within a sand-filled fuse tube sealed at both ends by brass end caps which are magnetically formed and epoxied thereon. The main fuse element is electrically connected at each end to a respective end cap by terminal tabs of the element terminations which extend through matching openings in the caps, and are soldered therein to hermetically seal the openings.

Abstract: An interrupter includes a vacuum enclosure for a set of high voltage contacts and end contact assemblies are secured to the end walls. High voltage terminals are connected to the contact assemblies. A solid insulating shell intimately attaches to the vacuum enclosure and extends axially therefrom to enclose the contact assemblies, with a contact shaft passageway in one end of the shell. One of the contact assemblies includes a movable contact shaft extending through the passageway in the insulating shell to an operating mechanism for rapid opening of the contacts. The passageway is sealed at the outer end to the shaft with a rolling diaphragm and defines a chamber encompassing the contact assembly. A deaerated insulating oil fills the chamber and significantly increases the impulse voltage rating of the interrupter. The chamber may alternatively be filled with a non-pressurized sulfur hexafluoride or other suitable gaseous medium to prevent contamination.

Abstract: A fitter for mounting a luminaire, such as an outdoor floodlight, on a mounting member, such as a pole, employs three castings. A first casting is affixed to the luminaire and is rotatable with respect to a second casting, which is releasably connected to the mounting member. The mechanism for locking the first and second castings in the desired angular position with respect to one another is enclosed within the castings. A chamber in the second casting contains electrical connections between power lines and electrical leads to the luminaire, as well as a portion of the locking mechanism. This chamber is enclosed by a third casting. Mounting of the second casting on the mounting member is achieved by the utilization of tapered surfaces, which permits use of different sized poles, and the second casting is clamped to the pole by set screws at the corners of the second casting, which has a base portion with a substantially square cross section.

Abstract: A hinge assembly for removably mounting an oven door on the front wall of the cabinet of a food processing oven for movement between open and closed positions with respect to the oven cavity includes a hinge plate mounted in overlying relation with respect to the front wall at one side of the oven cavity, a hinge arm on which the oven door is removably mounted pivotally attached to the hinge plate, a support arm joined pivotally at one end to the hinge arm and extending into the oven cabinet alongside the oven cavity through an aperture in the hinge plate and an aligned aperture in the front wall of the oven cabinet and a spring attached at the opposite end of the support arm and cabinet frame, to bias the oven door to a "closed door" position.

Abstract: A fusible element for a current limiting fuse includes two silver ribbons, each provided with a plurality of holes spaced apart along the length thereof which define fusible points of reduced cross sectional area, one of these ribbons including a conventional "M" spot consisting of a body of low melting temperature alloy such as tin-lead solder, in intimate contact with the silver ribbon. One end of each of the silver ribbons is joined to a respective end of a centrally disposed tin wire element by a copper interconnecting member. This tin wire central portion of the fusible element has a melt I.sup.2 t which is equal to or greater than that of the silver ribbons in series with it.

Abstract: A method of electrically and hydraulically connecting a conductor bar having a plurality of hollow water-cooled conductors involves compressing the conductor bar and shims of brazing material in a connector clip formed of a pair of mating clip members. Brazing shims (strips and bands) are placed in desired positions, and then the components are heated and hydraulically compressed. The conductor bar and brazing material assembly is sized for a tight fit in one dimension, but oversized in another dimension so that compression results in a desired distribution of the molten brazing material. During compression, the clip members are secured from relative motion, other than displacement toward one another, and air is passed through the hollow conductors to prevent the accumulation of brazing material in the open ends thereof. In addition to the clip members, the connector device includes a water inlet member with a stem that is inserted between and brazed to the clip members after the compression step.

Abstract: A bridge circuit including an eight-leg full wave rectifier bridge connected to rectify the phase and neutral currents produced by three wye-connected current transformers magnetically coupled to respective phases of a three-phase electric power circuit, and used with one or more resistive elements to provide instantaneous D.C. voltage outputs at least once every current cycle, proportional to the highest and/or lowest peak phase current and to the peak neutral or ground current of the power circuit, for operating or preventing the operation of a circuit interrupter in the power circuit being measured.

Abstract: The effective movement range of a rolling support such as a flexible chain linkage for electrical conductors and/or fluid conduits is materially increased by the provision of one or more retractable roller supports for the elevated cantilevered section of the rolling support upstream from its lower anchored end. The retractable roller support allows the rolling loop portion of the rolling support to pass through the retractable roller support in either direction. The weight of the rolling support is utilized to bias the retractable roller support toward its active supporting position.

Abstract: A power-driven tool for cleaning insulation and corrosion from conductors is portable and applies a controlled pressure established by hand. The tool employs a motor-driven abrasive drum and a pressure pad movable toward and away from the abrasive drum, with the conductor being squeezed between the pad and the drum during operation. A control for the motor is activated by the motion of the pressure pad toward the drum beyond a preestablished point, and an adjustable stop estalishes a minimum spacing between the pressure pad and the abrasive drum. A shroud covers the drum at all points except for an exposed area between the drum and the pressure pad, and a bias spring urges the pressure pad away from the drum to stop the motor upon release by the operator.

Abstract: An improvement in a high voltage, full-range, current limiting fuse of the type which includes a perforated ribbon main fusible element wound about a gas evolving spider within a sand filled enclosure, and having a portion in intimate contact with a body of low melting temperature alloy, and an auxiliary fusible element whose ends are closely spaced from the main element on opposite sides of the alloy body.The portions of the main element in contact with the alloy body, and adjacent the ends of the auxiliary element are relatively long portions having a uniform cross sectional area less than half the cross sectional area of an unperforated remaining portion of the main element, to thereby reduce the time required for the fuse to clear the low magnitude fault current.

Abstract: A grass trimmer employing a short length of nylon or the like line as the cutting element includes an assembly for removably attaching the line to a rotatable drive member. A hub member is coupled to the drive member for rotation. A post member extends from the free end of and parallel to the axis of rotation of the hub member. A rim portion also formed on the hub member, extends along a portion of the periphery thereof and defines a radially extending aperture therethrough. A length of line to be attached for rotation includes an eyelet connector at one end thereof. The opposite end of the line is received in the aperture in the rim portion so that the line extends radially outwardly from the hub member. The eyelet aperture receives the post member for removably attaching that end of the line to the hub member. A preferred embodiment of the cutting line has a triangular cross section to provide cutting edges extending the length of the line.

Abstract: A venting system for a food processing oven includes a duct assembly comprising a housing defining an inlet into which heated air from the oven enters and first and second outlets through which the heated air is expelled to the interior or exterior, respectively, of the household in which the oven is installed. A serpentine channel formed by a series of parallel plates mounted in the housing between the inlet and outlets is provided to carry the heated air over a relatively long path to cool, permitting water vapor therein to condense on the plates before the air is expelled. A damper plate is mounted in the housing for pivotal movement in the path between the inlet and second outlet. A manual selector movable to first and second positions is coupled to the damper plate for movement thereof to blocking and unblocking positions, respectively, with respect to the second outlet.

Abstract: A combination door handle and security locking system in which the conventional door latch is actuated by turning the five-sided head of an operating shaft with a special socket wrench. A hinge plate having a slot for a padlock bail and a flat index tab on its inner surface is rotated to cover the operating shaft head. The tab must fit against one side of the operating shaft head to allow the hinge plate to be fully closed so that a padlock can be inserted in the bail. The latching mechanism is designed so that this tab will fit against one side of the operating head when the door is fully latched, to thus prevent rotation of the latching mechanism. The free end of the hinge plate has an offset portion which serves both as a sleet hood for the padlock and as a handle for opening the door.

Abstract: A portable electric space heater has a case that surrounds separate electric heating elements, and the case has separated upper and lower airflow openings. A control switch allows manual selection of two different operating cycles, respectively suited for heater use in a large room requiring heater outputs approximately 65 to 100% of maximum to maintain a comfort level, and in a small room requiring heater outputs of only 20 to 100% of maximum. Thermostatic controls respond to the sensed ambient air temperatures to shift the heater operation automatically, in either operating cycle, for maximum heat output, for a lower modulated heat output, and for no heat output. Simultaneously with this modulated heat output, air moving means located in the case is operated at different speeds, at maximum speeds for the high heat outputs and lesser speeds or is even stopped for the lower or no heat outputs.