Abstract: An arc quenching composition suitable for deionizing and extinguishing a high voltage electrical arc comprising an effective proportion of hexamethylenetetramine. Depending on the application in which the arc extinguishing composition is employed, the hexamethylenetetramine may be utilized alone, admixed with a suitable binder, or used to impregnate another material.

Abstract: A reusable control module mountable to a power-cartridge-operated interrupting module which includes a normally closed switch in shunt with a fuse. The control module houses a control circuit which ignites the power cartridge to open the switch. The control module includes two conductive shells threaded together to enclose the circuit, thereby providing a Faraday cage for the circuit and shielding the circuit from the environment. A current transformer is mounted in an exterior pocket in one of the shells over a mounting terminal thereon which extends out of the pocket to act as a single-turn primary for the transformer. The output of the transformer is connected to an input of the circuit. Circuit boards of the circuit are mounted within the shells, in part by a plastic plug, one end of which passes through one of the shells coaxially with a mounting neck. The other end of the plug has slots which engage and hold one edge of the boards. The plug contains a conductor connected to the output of the circuit.

Abstract: A female contact of an interrupter includes a number of flexible fingers in a cylindrical array defining a cavity toward the axis of which the fingers are biased. A pair of semi-annular refractory members are located at the free ends of the fingers and define a passageway which is continuous with the cavity. The members are not welded or brazed to the fingers and are, accordingly, transversely free-floating relative to the fingers; they can move laterally of the axis independently of the fingers, but are prevented from movement along the axis. When a male contact is out of the cavity and the passageway, the fingers act against the exterior of the members until facing stop surfaces on the members abut, setting the minimum size of the passageway, which is smaller than the diametric size of the male contact but larger than the diametric size of the cavity between contact buttons on the fingers.

Abstract: A brake and operation indicator for a movable contact of a switch, the movable contact being rapidly moved by ignition of a power cartridge to open the switch. A thin-walled sleeve is positioned conformally about a movable pin, a portion of which is lightly held in a bore of an end member of a housing for the switch. The sleeve is shorter than the distance between a head on the pin and the end member. The bore is normally closed by a thin membrane. When the contact is moved, it ultimately abuts the head, moving the pin through the membrane to a position beyond the end member where a portion of the pin is visible. Movement of the pin also collapses the sleeve between the head and the end member in accordion-like fashion to dissipate the kinetic energy of and stop the contact. The presence of the pin within the sleeve renders the collapse controlled, uniform, and efficient. The visible portion of the pin informs that the switch is open.

Abstract: A door interlock for electrical apparatus, which may include a switch, within an enclosure, permits the door of the enclosure to be opened only if the electrical apparatus is in a predetermined condition, such as switch-closed. Once the switch has been opened, the door may be opened. The interlock prevents the switch from being reclosed as long as the door is open. A latch holds the door closed if the switch is closed, if the door is locked closed by a door lock, or if both conditions obtain. If the switch is opened while the door is locked closed by the door lock, the latch continues to latch the door closed. If the door lock is unlocked while the switch remains closed, the door latch likewise latches the door closed.

Abstract: Erosion- and decomposition-caused deterioration of exterior regions of an arc-extinguishing housing included in a high-voltage switch is eliminated or reduced. The switch also includes a stationary contact within a sealed chamber defined by the housing and a switch blade movable into and out of engagement with the stationary contact through a slit communicating with the chamber. The stationary contact and the switch blade are connectable to opposite sides of a high-voltage source. The deterioration-prone region of the housing resides between one housing portion which is connected to and is at the voltage of the stationary contact, and another portion which is essentially electrically floating. Deterioration is eliminated or reduced by closely capacitively coupling current to the region from a conductive projection connected to the stationary contact. The projection is closely spaced from, and may be either above or below, the region.

Abstract: A high-voltage circuit-interrupting device includes a replaceable container of pressurized arc-extinguishing fluid. A fluid port of the container is closed by a puncturable seal. When an overcurrent occurs in the circuit, the seal is punctured before interrupting contacts of the device open so that the fluid is already flowing when an arc forms between the contacts. Overcurrents are sensed by either a fusible element or a current transformer. Fluid flow before contact opening is achieved by mechanical facilities responsive to the melting of the fusible element or the output of the transformer. The entire device--including the container, the overcurrent sensor and the mechanical facilities--is at the voltage of the circuit.

Abstract: A high-speed switch usable at high voltage includes a pair of contacts movable apart along a fixed line. When the contacts are normally interconnected, at least one of them contributes to the definition of an enclosed chamber. Pressurizaton of the chamber by the ignition of a power cartridge therein rapidly drives the contacts apart, forming a first gap between them. When the contacts are interconnected, a first one of them is electrically connected to a terminal. As the contacts move apart, a second gap forms between the first contact and the terminal. The second gap is electrically insulated and may both be shielded from the ignition products of the cartridge and have any arc forming therein constricted and subjected to arc-extinguishing gas. The contacts may be shunted by a fuse to which current is commutated after the contacts move apart.

Abstract: Apparatus for preventing two switches from being simultaneously closed. A pair of rollers are each movable in, and between the ends of, respective curved tracks. The rollers are each linked to a respective switch so that when its switch is closed, each roller is at the bottom of its track, and when its switch is open, each roller is at the top of its track. Each switch cannot operate if its roller cannot move. A yoke maintains the rollers a fixed distance apart so that each roller may be at the top of its track, one roller may be at the top of its track while the other roller is at the bottom of its track, and vice versa, but one roller cannot move away from the top of its track if the other roller is not at the top of its track and vice versa. If one switch attempts to close while the other switch is closed, the roller of the closed switch is pulled into a detent at the bottom of its track; the roller remains in the detent as long as the other switch attempts closure.

Abstract: A fusible element of a current-limiting fuse has a plurality of hole groups with at least two holes in each group. Separation between adjacent holes within the group is substantially less than separation between adjacent groups. Accordingly, while fault currents driven by voltages at two different levels are effectively extinguished, the back voltage developed by the fuse during interruption of a fault current driven by the lower voltage is prevented from exceeding a selected value.

Abstract: A combined pressure relief and pressure indicating mechanism includes a diaphragm closing a vent in a housing. The diaphragm is punctured if an excessive overpressure occurs in the housing to relieve same. A movable indicator is held from moving by the diaphragm as long as the housing pressure exceeds a minimum value. If the housing pressure falls below this value the indicator moves, its movement giving a visual indication of an underpressure.

Abstract: Disclosed in a high voltage switch operating mechanism which utilizes energy stored in a spiral spring to drive the high voltage switches from either the open to the closed or the closed to the open position. The spring can be charged either by a manual tool or by an electric motor. The switch can be tripped by either electric or manual trip mechanisms. Manual and electric trip interlock assemblies are provided to prevent the switch operating mechanism from being tripped either manually or electrically while the spring is being charged. A mechanism is provided to prevent the charging of the spring by the electric motor when the manual tool is used to charge the spring. Another mechanism is provided to decouple the operating mechanism from the switch. To allow testing of the operating mechanism without change of the switch state. The decoupling mechanism locks the switch to its present position before the decoupling is complete allowing the energy in the operating spring to be dissipated.

Abstract: A pressure- and weather-resistant fuse tube having fiberglass reinforcement which cannot interfere with arc-extinguishment and which does not require an insert or liner of arc-extinguishing material. The fuse tube is molded from a thermosetting material which includes an effective amount of an arc-extinguishing material. The fuse tube includes an inner bore-defining portion and an outer weather-resistant portion which are simultaneously molded along an interface at which is located a layer of porous fiberglass cloth, or filament. The fiberglass is sufficiently porous to permit the material of both portions to pass through and thoroughly impregnate it, thereby locking both portions to each other and to the fiberglass which is located well away from the bore thereof.

Abstract: A detector for high-voltage, polyphase gear, having a fuse-switch combination in each phase and a switch operator, includes voltage sensors which provide first time-varying signals indicative of the magnitude and phase orientation of the phase-to-ground voltages on each phase within the gear at the load side of the fuses. The first signals are vectorially added to provide a second time-varying signal, the peak value of which varies as the magnitude and phase orientation of the phase-to-ground voltages of the phases. The second signal is compared to a reference; an error signal is generated when and as long as the phase-to-ground voltages vary beyond set limits. A timer responds to the error signal and provides a third signal a predetermined time after initiation of the error signal, but only if the error signal persists for such time. The third signal is used to cause the operator to open the switches.

Abstract: Disclosed is an arcing rod catcher for a high voltage fuse which engages the arcing rod when the arcing rod moves during fuse operation so that the arcing rod will not bounce back or reverse directions during and after fuse operation. Since the arcing rod movement is utilized to actuate a fuse latch assembly to release the fuse from an upper mounting when it operates, it is necessary for the arcing rod to move to the operating position and remain in that position to permanently indicate that the fuse has operated and to prevent the possibility that a blown fuse will be re-latched into a closed position. The disclosed invention utilizes engaging fingers which allow the arcing rod to pass in one direction but prevent the arcing rod from returning in the opposite direction when the fuse operates.

Abstract: A high speed high voltage electrical switch opens a current path in which the switch is included. The switch includes first and second normally electrically interconnected contacts which normally carry current in the current path. The contacts are relatively movable along a fixed line of direction. When the contacts move apart, the electrical interconnection therebetween is broken to open the first current path. A piston carried by the second contact defines an enclosed chamber in conjunction with the first contact when the contacts are interconnected. A power cartridge or the like selectively pressurizes the chamber to rapidly drive the contacts apart. The piston enhances the action of the power cartridge by ensuring that pressure increases caused thereby are effected to drive the contacts apart. The piston may be configured to ensure positive sealing engagement with the walls of a cylinder through which the piston and the second contact move following the ignition of the power cartridge.

Abstract: In high-voltage switchgear, apparatus for preventing two switches from being closed at the same time to prevent their being electrically paralleled relative to a common bus. The position of each switch is mimicked by a rotatable cam having a notch. When either switch closes while the other switch is fully open, its cam moves a member into the path of the notch in the other cam which is blocked from rotating, preventing the other switch from closing. If both switches attempt to close simultaneously, the member either blocks both cams or blocks one while permitting the other to rotate. If one switch attempts to close while the other switch is closed, and if the one switch continues to attempt closure through the time the other switch opens, its cam continues to be blocked until the one switch is returned to full open.

Abstract: A pre-insertion resistor mechanism for a circuit interrupting device of the type which has a pair of normally-engaged contacts. One of the contacts is movable relative to the other contact in an arc-extinguishing environment to selectively separate the contacts to open a gap therebetween to effect circuit interruption. The contacts are continuously, electrically connected to respective, opposed circuit-connectable terminals on the device. The pre-insertion resistor mechanism includes a pre-insertion resistor electrically connected at one end to one of the terminals. The other end of the resistor carries a stationary electrode. A movable electrode assembly which is electrically connected to the other terminal is mechanically coupled to the movable contact so that upon movement thereof to open the gap, the movable electrode simultaneously separates from the stationary electrode.

Abstract: An improved fuse link has a fusible element attached between first and second terminals. The first terminal is attached to, or integral with, a length of flexible stranded cable. The terminals, the fusible element and some of the cable are within an arc-extinguishing sheath. The cable is unified and stiffened for a selected distance immediately adjacent the first terminal to act thereat substantially as a solid rod. The unified region acts as a guide for the first terminal moving through the sheath, reduces binding friction between the cable and the sheath, and eliminates "mushrooming" of the cable within the sheath.

Abstract: A single-vented fuse tube has a bore lined with an arc-extinguishing material. A movable contact moves away from a stationary contact in the bore and toward and out of an exhaust opening. An arc established between the contacts causes de-ionizing arc-extinguishing gases to evolve from the bore. The gas is exhausted from the exhaust opening. The bore is mildly tapered--to about 1.degree. to 3.degree. of included angle--so that its greatest diameter is at the exhaust opening. The included angle and extent of the taper are sufficient to obviate stagnation of the gases evolved deep within the bore and clogging of the bore.