Abstract: A current limiting iron wire resistor having a transformable resistance for a current limiting circuit breaker. Each pole of the circuit breaker includes said resistor in parallel with a pair of auxiliary contacts for current limiting which are in series with a pair of main contacts to open the circuit. The main contacts are separable upon operation of a thermally and electromagnetically operable tripping mechanism, and the auxiliary current limiting contacts separate only on occurrence of a high amplitude fault current above a preselected threshold value. When that value of fault current is reached, the tripping mechanism and associated components which operate the auxiliary current limiting contacts serves to increase arc voltage almost instantaneously to that of the source, about which time the fault current is totally shunted into the current limiting resistor.

Abstract: A single phase electrical panelboard so arranged as to be compatible with three phase systems. Circuit controlling elements may be fitted to the panelboard, the circuit controlling elements being mechanically supported on a first support rail arranged parallel to the bus-bar so as to engage electrically terminals fitted to the bus-bar. Additionally, panelboard is provided with a second support for the circuit controlling elements, the second support being in the form of a flat strip having an edgewise relationship to the bus-bar and located in a base plate at each of its ends.

Abstract: The following specification describes a bimetal in the limiter assembly of a circuit breaker to operate the trip crossbar for opening the main circuit breaker contacts. An arm is also provided on one blade of the current limiter contacts to also operate the trip crossbar for ensuring rapid opening of the main contacts of the circuit breaker in response to high fault currents. The bimetal is connected between the electromagnet winding and one of the current limiter contact blades in shunt with a path of selected resistance. The resistance is selected as desired by connecting pigtail conductors of desired size either in shunt with or to selected portions of the bimetal to control the current passing through the bimetal for controlling the heat of the bimetal in accordance with the rating of the breaker. A calibration assembly for the bimetal is carried by the electromagnetic assembly.

Abstract: The following specification describes a double rabbet on the back of a panelboard cover for nestingly receiving a flange on the panelboard hopper. This permits proper cover adjustment irrespective of cabinet misalignment and prevents the deliberate insertion of an object past the hopper to possibly engage a live circuit at the interior assembly of the panelboard.

Abstract: An electrical load center comprising an enclosure having a bus bar assembly extending longitudinally thereof, and the bus bars being mounted on an insulated base. A pair of end base plates support the bus bar assembly, the end base plates being formed of insulating material and mounted in the enclosure at respective ends of the bus bar assembly to receive a selected one of a plurality of terminal support means, terminal barriers or cover plates.

Abstract: The following specification describes a bus stab for a panel-board assembly comprising a U shaped bus stab arranged to establish a connection to either a spring clip terminal of a plug-on type circuit breaker or to a bolt-on type terminal of a circuit breaker.

Abstract: The following specification describes a magnetic assembly for use in controlling the main contacts of a circuit breaker. The magnetic assembly includes a yoke, an armature for attraction to the yoke to move an operating lever and a pivotable adjustment arm. The lever operates the trip crossbar, which opens the main contacts and is in turn pivotably carried by the adjustment arm. One end of the operating lever is held against longitudinal movement relative the trip crossbar, when the adjustment arm is pivoted to calibrate the circuit breaker. The lever therefore pivots on the adjustment arm to move the armature towards or from the yoke to control the armature air gap without altering the lever travel distance to the crossbar. The armature is also mounted on the lever for relatively linear movement in relationship to the yoke.

Abstract: A multi-pole circuit breaker includes a wide toggle shaft which spans all of the poles of the breaker and which is electrically neutral. The lower links of the toggle mechanism are made of phenolic or other insulating material which thus electrically insulates the wide toggle shaft spanning all of the poles of the breaker and makes the toggle shaft electrically neutral. A plurality of short toggle springs may therefore be connected between the wide toggle shaft and a handle arm of corresponding width. The plurality of short toggle springs provide as much tripping energy as the longer single or double toggle springs of prior art circuit breakers in which the springs are clustered together in alignment with one pole of the breaker to which they are electrically connected and whose polarity the toggle springs in such prior art breakers accordingly take.

Abstract: A bus duct system comprising straight sections of bus duct, bracing members in said bus duct to support a plurality of flat bus bars in spaced apart relationship, access opening for tap-off boxes having sliding doors to open and close said access openings. The bus duct sections include slots in the walls of the bus duct to receive projections of the bracing members to hold the bracing members in position within the bus duct. The bracing members are located adjacent the access openings to provide stability for connecting a tap-off box to the bus bars.

Abstract: A flexible connector for connecting a circuit breaker in a panelboard wherein the connector comprises a plurality of thin metal straps which are fused together at each end. One end includes an aperture to receive a bolt for bolting to the bus bar of a panelboard. The other end of the flexible connector includes the stationary contact of the circuit breaker, and this end is trapped in the circuit breaker with the stationary contact in position for engagement with the movable contact of the breaker. The flexible connection extends outwardly from the breaker and may be doubled under, so when bolted to the bus bar of the panelboard, the bolted end of the connection lies under one end of the circuit breaker. In a modification a jaw member is included at an intermediate point between the stationary contact end and the bolt receiving end of the connector.

Abstract: The following specification describes a panelboard assembly comprising a plurality of modular insulators each having an integrally formed resilient bead for engaging a circuit breaker housing recess to support a circuit breaker. A tongue on each insulator assists in disengaging the circuit breaker from the bead. Longitudinally extending bus bars are supported by the insulators in heat transmitting relationship to the metal wall of an enclosure. The insulators have long surface paths between adjacent bus bars and bus stabs to prevent electrical leakage. A neutral assembly in close space saving relationship to the bus bars and for convenient wiring is provided together with partition walls between phase bus bars and between individual bus stabs.

Abstract: A motorized drive assembly for a circuit breaker operator comprising a follower mounted on a free wheeling double helix shaft which extends in the direction of movement of the operator between "TRIP," "RESET" and "ON" positions, the shaft being driven by an electric motor through a disengageable gearset controlled by a solenoid. The follower engages the operator, and upon rotation of the shaft the follower moves in one direction carrying the operator from a TRIP position to a RESET position. At this point, the follower has moved as far as one of the double helices will carry it in that direction, whereupon internally projecting lugs of the follower engage the other helix for movement in the opposite direction to carry the operator from the RESET to the ON position in which the breaker contacts are closed.

Abstract: The following specification describes a cover for a panelboard with the cover carrying spring biased latch clamp assemblies for engaging the flanges formed on the side walls of the panelboard cabinet.

Abstract: The following specification describes a circuit breaker trip crossbar having diverging radial surfaces receiving a tapered rail therebetween. The rail extends from the bottom edge of the conventional breaker barrier wall recess and forms a small area pivot adjacent the crossbar axis to reduce the torque required to pivot the bar and to render the torque reproducible for calibration purposes.The radial surfaces are economically formed by flat mold surfaces in opposite mold halves to avoid mold flash in the pivot area while enabling one of the mold halves to conventionally form the latch plate securing hole in the crossbar.

Abstract: The following specification describes a meter receptacle assembly utilizing an outer collar to overlap the meter flange base and latched to the cabinet in which the meter is mounted by interlocked tabs and a sealing wire. A trim or cover plate for the cabinet in turn overlaps a flange wall on the collar and is locked to the cabinet to prevent removal of the collar and unauthorized bypass of the meter. A cutout in the cover plate provides access and visibility for the sealing wire. Authorized bypass connections for the meter to permit its removal without disturbing service are facilitated by horn terminals whose ends project beyond the meter periphery to permit facile connections thereto.

Abstract: A transducer to monitor velocity and direction of movement having a magnetic core with at least three spaced apart poles. Two of the poles include coils which are wired series aiding for connection to an input alternating voltage, which upon current flow create a magnetic field intersecting the path of movement of an object being monitored. The third pole includes a coil in which an alternating output voltage is induced when the monitored object moves. The magnitude of such output voltage varies with the rate of speed of the monitored object. The phase relationship of output voltage to input voltage varies with the direction in which the monitored object moves. The coil in the third pole is connected to responsive means to receive the output signal and control, or indicate, the speed as well as the direction of movement of the monitored object.

Abstract: The following specification describes a padlock adapter assembly comprising a pair of identical stamped plates each having a pair of spaced passages aligned with a respective passage in the other plate to form a pair of aligned passages for receiving a respective padlock shackle. A hook on one end of each plate is pivoted toward or away from the other hook about an axis through either pair of aligned passages when the respective one of two padlock shackles is removed to permit access to an enclosure.

Abstract: A rotary tap changer or switch is rotated by a motor to a plurality of contactor positions by a control system having a cam that rotates to activate limit switches respectively corresponding to contactor positions. The activation of the limit switches causes operation of a relay which, after a selected time delay, operates to discharge a capacitor across the motor to apply dynamic braking and stop the motor. When starting the motor to rotate the tap changer, energization is applied through the limit switches to select rotation in a forward or reverse direction determined with some modification by the shortest distance of rotation to the new selected position.

Abstract: A current limiting circuit breaker having for each pole, a pair of main contacts separable upon operation of a thermally and electromagnetically operable tripping device and a pair of auxiliary contacts for current limiting in series with the main contacts and in parallel with a transformable resistor having a positive temperature coefficient of resistance. The auxiliary contacts are separable when an electromagnet is energized by a fault current which simultaneously energizes a field magnet to produce a transverse magnetic field across the auxiliary contacts and the arc formed between them when separating. This simultaneous action of electromagnet and field magnet coacting for rapid contact separation and lengthening of the arc upon flow of a fault current serves to increase arc voltage almost instantaneously to that of the source, about which time the fault current is totally shunted into the resistor.

Abstract: An iron wire resistor connected in shunt with the current limiting contacts of a circuit breaker. The current limiting contacts are in series with the main contacts of the breaker, and are separated by extremely high fault currents before the main contacts can respond. Opening of the limiting contacts shunts the high fault current through the resistor. The resistor has a positive temperature coefficient of resistance and heats rapidly to sharply reduce the magnitude of the high fault current.To prevent the connection between the resistor and a low resistance copper conductor from being destroyed by the high fault current an intermediate resistance value terminal of copper clad stainless steel is employed between the resistor and the copper conductor.