Abstract: A ground connector for a jacketed, interlocked armored cable includes a body portion, a resilient grommet, a frictional washer and a compression nut. A longitudinally split metallic grounding ring is also provided. A first end of the grounding ring is seated in a bore formed interiorly of the body portion. The opposite second end of the grounding ring is provided with a plurality of fingers as well as generally U-shaped connecting sections for joining the fingers to the second end of the cylindrical wall of the grounding ring. The connecting sections and the fingers are both deflectable upon assembly of the connector. The fingers, which are initially at an angle with respect to the longitudinal axis of the connector, point in the same direction as the direction of cable assembly. The free ends of the fingers act like barbs to thereby minimize retraction of the cable.

Abstract: A differential transformer having a core of low permeability ferromagnetic material, a pair of identical primary windings and a secondary winding of relatively few turns capable of producing a large voltage output for a small magnitude ground fault current. A cross-field winding is utilized to periodically saturate a portion of the flux path in the transformer core to produce sudden changes in magnetic flux, which flux changes vary in magnitude proportional to the amount of fault current. During the time interval when the cross-field portion of the sensor is not saturated by a pulse of sampling current, a second pulse of current is introduced into the sensor secondary winding for detecting a grounded neutral wire by sensing the output voltage produced in response thereto.

Abstract: In a circuit breaker, the movable contact carrying contact arm is pivotally connected to the contact carrier which pivots on the circuit breaker frame; the contact arm is stamped copper; the contact arm carrier pivot connection includes a pin passing through the walls of the carrier and with respect to which the contact arm pivots; also, improved means for establishing pressure of movable contacts.

Abstract: A vapor-proof connector on a metal electrical conduit includes an externally threaded tubular body engaging the end of the conduit and a gland nut spaced inwardly of and engaging the tubular body. The gland nut has an inwardly directed peripheral flange with a tapered inside face confronting a tapered end face of the body to delineate an annular space which surrounds the conduit and houses a channel-shaped split metal ring having inwardly directed diverging flanges and a wedge-shaped deformable gland ring arranged end to end so that tightening of the gland nut compresses the gland ring between the metal ring and the body or nut to radially compress the inside face of the gland ring and cause the split ring to bite and anchor to the conduit. Alternatively, the gland ring may be encircled by the split ring. The ends of the split ring may have opposing reduced width tongues extending therefrom.

Abstract: A baffle assembly covering a vent opening in a molded case circuit breaker housing is constructed of two identical platelike elements having integral face protrusions. These elements are stacked in face-to-face relationship with their protrusions in engagement to maintain a narrow space between the element faces. Edge notches are provided to orient the elements so that the perforations of one element are misaligned with respect to the perforations of the other element so that arcing gases do not flow in a straight path through the baffle assembly.

Abstract: An insulator for supporting a high voltage conductor within a gas-filled grounded housing consists of radially spaced insulation rings fitted to the exterior of the bus and the interior of the grounded housing respectively, and the spaced rings are connected by trefoil type rings which are integrally formed with the spaced insulation rings.

Abstract: A pneumatic timer is constructed by stacking a calibration subassembly on top of a diaphragm housing stacked above a diaphragm subassembly, and including a filter capsule subassembly interposed between the calibration subassembly and the diaphragm housing. The filter capsule subassembly includes a check valve disposed within a recess so constructed that all air entering the recess must pass through filter screens disposed on opposite sides of the check valve. The biasing spring for the check valve bears against one of the screens and biases the movable valve member to a normal position bearing against the other screen. The second screen is flexible so that at the end of the reset stroke the plunger attached to the timing chamber diaphragm mechanically opens the check valve.

Abstract: A ferrule fuse terminal clip with a pivoted U-shaped rejector member extending between its complementary curved clip legs. The pivotable rejector member facilitates the insertion and removal of a low rated-current cartridge fuse having a grooved ferrule end terminal and prevents the insertion of a non-grooved ferrule terminal of a cartridge fuse having a higher rated current. The rejector member is easily installed in a conventional ferrule fuse terminal clip and cannot be removed therefrom utilizing common tools without rendering the fuse terminal clip unusable.

Abstract: Electrical insulation grade concrete is prepared by mixing the aggregate and cement with an excess of water and thereafter vacuum deaerating and vacuum dehydrating the resulting mixture.

Abstract: An assembly of overload relays is mounted so that the reset handles are spaced a substantial distance from the operable cover of the enclosure wherein the relays are mounted. A reset extension is provided for resetting all relays simultaneously by depressing a single reset button mounted on the cover. The reset extension is constructed so as to be self securing to the overload relays, and is mounted and dismounted without requiring tools.

Abstract: A molded case circuit breaker having a spaced plate arc chute for each pole thereof, with each arc chute having a V-shaped mouth region at one end and having separable arcing contacts positioned at the mouth region and having a space defined opposite the mouth region and between a cover plate region and a terminal bus for obtaining access to terminal mounting bolts, is provided with at least one arc chute extension attached to a cover panel portion. Each arc chute extension consists of a plurality of spaced conductive plates and insulated means for rigidly positioning each of the plates in close planar alignment with a plate of the arc chute to present an increased length serpentine path for extinguishing an arc produced by the interruption of voltages and currents in excess of the original arc chute rating. Arc chute extensions are introduced as a single unit to increase the interruption rating of as many poles of the circuit breaker as is required.

Abstract: A counterbalance valve assembly for controlling the lowering of an actuator driven load including a housing with a passage connected to deliver fluid to or from one side of the actuator. A main pilot-operated lock check valve is provided in this passage to selectively block flow from the actuator when it is desired that the load be held and also to move to an open position permitting return flow from the actuator with the open valve defining an orifice. The speed of the load is controlled by maintaining a constant pressure drop across this orifice with a compensator valve upstream of the main check valve, which serves the purpose of throttling flow from the actuator to the check valve.

Abstract: The stabs on a busbar for mechanically and electrically receiving circuit breakers, or the like, are shaped so as to have two mutually perpendicular contact plug-in elements on a single stab enabling the single stab to receive circuit breaker contacts that are oriented in mutually perpendicular directions.

Abstract: An electrically releasable permanent magnet latch includes a magnetic tube disposed within a U-shaped magnetic form. Disposed within the tube are a lightweight armature and a coil spring biasing the armature forward. An electromagnet coil is wound about the rear portion of the tube and a pair of permanent magnets are inside the frame along side the front portions of the tube. Energization of the coil creates a flux which bucks the permanent magnet flux to permit the spring to overcome the armature holding force whereby the spring operates the armature.

Abstract: A fixture is disclosed for holding a tubular workpiece during the machining thereof. The fixture includes a base plate that is adapted to be placed over a mandrel that supports the workpiece. A pair of spaced apart blocks are slidably mounted on the base plate and each includes a plurality of roller means that depend downwardly therefrom. Guide means are provided for the blocks which are displaced towards the axis of the workpiece by means of a pair of opposed air cylinders so that the roller means engage the periphery of the workpiece and center the workpiece with respect to the axis of the mandrel. The workpiece may then be machined such as by forming external threads thereon.

Abstract: A closure or bushing member for openings in electrical boxes, conduit ends and the like is formed as an integral unit of a thermoplastic synthetic organic polymeric resin and includes a disc or annular shaped head and a coaxial hollow cylindrical shank of lesser diameter. Extending from opposite sides of the distal end of the shank are a pair of opposite radially projecting arms, which terminate in wing members of greater width than the radial arms and which have conically surfaced outer faces flaring rearwardly outwardly. A peripheral recess is formed in the rear outer face of each wing to provide a rearwardly facing shoulder for resiliently engaging the inside border of the opening to which the closure member is applied to retain the closure member therein.

Abstract: An electrical conduit grounding device includes a clamp formed of a pair of similarly shaped screw connected clamp sections each formed of a web including a crowned medial section terminating in coplanar wings and provided with longitudinal flanges. One of the clamp sections is provided with a cable clamp at the crown apex and which is stamped and shaped from the web, leaving corresponding openings therein, and includes first and second laterally spaced vertical arms atop the crowned section, a longer arm terminating in a horizontal leg projecting toward and above the top of the other arm. The leg has a tapped vertical bore engaged by a cable clamping screw.