Abstract: A system for the emergency deenergization of a multibranch power circuit includes a ground fault circuit interrupter having capability to trip under both ground fault and grounded neutral conditions. A plurality of receptacles are provided on the circuit to receive connecting plugs of electrical devices to be powered. A removable plug adapted for insertion into any of the receptacles includes the series combination of a normally open pushbutton switch and resistor connected between plug pins which are in contact with the neutral and ground conductors of the circuit so that actuation of the switch when the plug is inserted in a receptacle establishes a low-impedance path from neutral to ground which is detected by the ground fault circuit interrupter. This causes the interrupter to trip and deenergize the circuit.

Abstract: A wide-range current limiting fuse assembly particularly adapted to protect capacitors. The device comprises a current limiting portion having a corrugated fusible ribbon for high fault current protection, and a low current portion having a fusible link surrounded end to end by a conductive metal sleeve connected to one terminal of the fusible link. The current limiting portion may, alternatively, be provided with a circularly cross sectioned fusible wire connected in series with the fusible ribbon.

Abstract: A circuit breaker having separable contacts, thermal and magnetic trip means, a flexible conductive braid connecting the contacts and the trip means, and a latch mechanism for producing a series of vibrating impacts upon overcurrent conditions also includes a latch member of electrically insulating material to prevent undesirable parallel current paths and to increase the interruption current rating of the breaker.

Abstract: An electrical switchboard including a horizontal main supply bus and a vertical riser bus mounted within a cabinet structure. The conductors of the vertical riser bus include front and rear flanges connected by a web portion to form an I-shaped cross section. Line side stab connectors are mounted directly to the front flanges using bolts and press nuts seated in the front flange. Riser support members and load side extension support members are mounted upon the rear flanges.

Abstract: A current limiting circuit breaker comprises an improved slot motor magnetic drive device. The threshold level of overload current which produces current limiting action is raised, yet the degree of current limiting action during high overload currents is maintained by placing a thin saturable magnetic steel plate across the open end of the slot motor magnetic drive device. During overcurrent conditions below the threshold value, the plate shunts most of the magnetic flux and prevents production of magnetodynamic force upon the contact arm. Above the threshold level, the overcurrent generates magnetic flux sufficient to saturate the plate and forces additional flux into the air gap where the flux interacts with the contact arm to drive the contact arm into the slot and produce current limiting action in a normal manner.

Abstract: Electrical switchboard apparatus includes a switchboard having a plurality of cells adapted to receive circuit interrupters and related electrical equipment, a weatherproof housing enclosing the switchboard and providing a maintenance area between the front of the switchboard face and the interior front wall of the enclosure, and a traveling lifting mechanism movably supported at the top of the maintenance area upon two parallel rails extending across the switchboard face and the interior front wall of the enclosure. The lifting mechanism is a bridge-type crane comprising a perimeter frame of U-shaped steel channel members and a flanged steel plate bolted thereto. The lifting mechanism also includes a winch and a pulley supporting a lifting cable attached to the winch. The pulley is supported upon a steel pin removably inserted into any of a series of holes in angled support members mounted within the perimeter frame.

Abstract: A three pole molded case circuit breaker including a push-to-trip button, a flux transfer shunt trip mechanism, an undervoltage trip mechanism, and an improved latch mechanism. The latch mechanism comprises a metal trip bar covered with insulating tubing and adapted for translational movement to actuate the latch mechanism and trip the contacts. Contact carrier movement during the tripping operation serves to reset the latch mechanism.

Abstract: An electrical distribution switchboard including a multiphase horizontal main bus and a multiphase vertical riser bus. A plurality of tie members are provided, one tie member being connected to each vertical phase member. Each horizontal phase conductor is connected to the tie member of its corresponding vertical phase conductor so as to symmetrically locate the top and bottom of each tie member above and below the horizontal centerline of the horizontal main bus, allowing the vertical riser bus to be fed at its electrical and geometric center.

Abstract: A circuit interrupter including a releasable latch restrained by a stamped metal rotatable cam having a latching surface in sliding contact with the latch member. The rotatable cam is inclined at an angle to the axis of rotation so as to cause only the smooth portion of the latching surface produced by the shearing action of the stamping process to contact the latch member. The rough portion of the latching surface produced by tearing action of the stamping process is not in contact with the latch member, thereby eliminating the need for a machining operation to provide a low friction contact surface with the latch member.

Abstract: An electrical distribution switchboard including a multiphase horizontal main bus and a multiphase vertical riser bus. A plurality of protective members are provided, each being vacuum formed from a thermoplastic carbonate-linked polymer material. Separate protective members are provided for each individual phase conductor of the horizontal and vertical bus.

Abstract: A framework for an electrical switchboard comprises four angled uprights, and top and bottom angled crossbars. The uprights and crossbars each have the same cross section and are formed of sheet metal folded into four parts. The first part is contiguous with and perpendicular to the second part having the same width as the first part. The third part is narrower than the first part and is contiguous with and perpendicular to the second part, and is also contiguous with and perpendicular to a fourth part. The first and third parts are located on the same side of the second part, while the second and fourth parts are located on opposite sides of the third part.

Abstract: A circuit breaker particularly adapted for use in an oil filled distribution transformer includes an improved bimetal trip actuator which exhibits greater deflection for a given degree of power dissipation. The trip actuator includes a planar bimetal element held relatively stationary at one end and free to deflect at the other end in response to overload current conditions through the circuit breaker. The bimetal element is constructed to have a higher power dissipation in proximity to the stationary end than in proximity to the deflecting end.

Abstract: An electrical distribution switchboard including a multiphase horizontal main bus and a multiphase vertical riser bus. Each individual horizontal phase conductor comprises a plurality of spaced parallel bars connected to the corresponding individual vertical phase conductor through an extruded aluminum block having a plurality of grooves formed in each side to receive the spaced parallel bars. The bars are welded in the grooves and the connector welded to the individual vertical phase conductor.

Abstract: An automatic transfer control device for selectively energizing an electrical distribution system from a pair of electrical power sources. The device includes voltage sensors for sensing electrical conditions on each of the sources. The device may be used on either three-wire or four-wire systems. The voltage sensors comprise an operational amplifier for artificially generating a phase-to-phase voltage from two phase-to-ground voltages. The artificially generated voltage is used to detect sequence reversal on the sources being monitored. Separate means are provided to select a source from which to draw control power for the device, the control power criterion being different from the transfer criterion.

Abstract: A self-powered self-contained ground fault protective device including a current monitor, an electronic circuit for amplifying the output of the current monitor, and a relay connected to the amplifying circuit and adapted to operate whenever ground fault current through the current monitor rises above a predetermined level. The current monitor, amplifying circuit, and relay are all supported and enclosed by a molded insulating housing.

Abstract: An automatic transfer control device for generating signals to cause associated circuit interrupters to selectively energize an electrical distribution system from either of a pair of electrical power sources. The device includes an over- and under-frequency monitoring circuit to determine if the power source frequency is within preset limits. The frequency monitoring circuit includes a zero-crossing detector which activates a clock oscillator, the output pulses of which are accumulated by a counter for one half cycle. The number of pulses occurring during the half cycle is compared with a limit value stored in a read-only memory. An alarm signal is activated if the number of pulses accumulated is out of limits.

Abstract: An automatic punch press and monitoring system. The monitoring system includes a piezoelectric accelerometer mounted within the stationary die shoe of the punch press, and electronic circuitry including a variable gain amplifier, a detector, an integrator, and a comparator. The monitoring system is manually placed in a "LEARN" mode whereupon the signal produced by the accelerometer during normal operation of the punch press is amplified, detected, and integrated over the time period of one stroke to produce a test function. The gain of the amplifier is automatically adjusted during successive normal strokes of the punch press until the test function is equal to an arbitrary set point, thereby establishing a reference function. The monitoring system is then automatically placed in an "AUTO CONTROL" mode whereupon on each succeeding stroke, with the gain of the amplifier fixed, the test function produced is compared with the reference function.

Abstract: A ground fault circuit interrupter comprises separable contacts for interrupting current flow through a power circuit being protected, trip means operable upon energization to effect separation of the contacts, means for detecting ground fault current, means for monitoring voltage upon the power circuit, and means responsive to the ground fault current detecting means and the voltage monitoring means for energizing the trip means when ground fault current reaches a trip current level. The trip current level varies as a function of the power circuit voltage.

Abstract: This invention relates to a distribution panelboard such as might be used for electrical service entrances. The panelboard differs from prior art designs in that the neutral rail which is generally found in previous designs at the top or bottom of the panelboard is located on each side of the panelboard. In this manner it serves to conduct the neutral currents to the neutral load and at the same time functions to anchor one end of a distribution circuit breaker thereto.

Abstract: A motor controller having a single set of contacts and two contact operating systems is provided for operation and protection of a motor and the associated circuitry over a complete range of possible currents. For a normal motor starter operation and for fault current up to a predetermined value, an electromagnetic actuator is used to open the contacts a relatively small distance such as 1/4 inch. For higher fault currents a magnetic drive or linear slot motor opens the contacts to a greater spacing such as 1 inch. The slot motor opens the contacts very rapidly giving rise to good current limiting. The disclosed integral motor starter utilizes a bridging contact arm on which are mounted a pair of movable contacts which are aligned to engage a pair of stationary contacts when the disclosed motor starter is closed, completing an electric circuit to the controlled motor.