Abstract: A continuous ribbon resistor element having a plurality of conjunctive lengths alternately connected by reflexes is supported in a frame comprised of silicon bonded laminated mica. The ribbon elements are formed with a single, flat convolution center offset to one side of an original plane and lateral portions offset to an opposite side of the plane, joined to the center offset by transition portions such that the centroid for any transverse cross section lies on the original plane. The offsets originate at flat end portions near the reflexes and have maximum offset intermediate the ends. Metal members are received in openings of the laminated mica insulators to receive threaded fasteners when attaching an insulator in edge-wise relationship to another. Thermally conductive termination connections are brought outside the frame and airflow passageway to remove from the passageway the additional heat otherwise absorbed by the terminals.

Abstract: A double pole single throw electric switch has normally closed contacts of one pole connected in a dynamic braking circuit with a motor load and normally open contacts connecting the motor to a source of power. A partial movable contact conductively connected to movable contacts of the normally open contacts is disposed in normally open position relative to one contact of the normally closed contacts to provide a parallel path through the switch for making and breaking the circuit to the power source.

Abstract: A subframe is coaxially pivotally mounted with a movable frame of the operating mechanism of a molded case circuit breaker and is locked to the frame by a bell crank pawl which is pivotally mounted on the subframe. A leaf spring assembly rigidly attached to the subframe overlies the movable contact finger to engage the same in the circuit ON condition of the circuit breaker to provide desired contact force. The bell crank pawl is released upon an incrementally small amount of initial movement of the movable contact arm in response to blow-open magnetic repulsion forces to release the movable contact finger for pivotal opening movement relative to the movable frame of the circuit breaker operating mechanism.

Abstract: Molded insulating shell halves are secured together around a blowout coil, stationary and movable contacts to pivotally trap an armature assembly therebetween. Windows are provided in the shell halves to ventilate the electromagnet coil during operation. The electromagnet is removable through the window without disassembly of the contactor. Contact and armature adjustment is accomplished through additional window openings. An arc chute having left and right-hand arc extinguishing chambers each sub-divided into upper and front chambers splits the arc into four series segments and increases the overall length of the arc significantly over similar prior art devices.

Abstract: A rigid insulating shield has tabs at a lower end inserted in slots in a case and a press-in fastener at an upper end inserted within a hole in a switch base assembly for securing said shield within the case. A handle pullout has a large flange extending over the shield when inserted in the switch base assembly to prevent removal or displacement of the shield while the handle pullout is inserted in an ON position of the switch. The flange is sufficiently large to block direct access to termination means on the switch base assembly when the shield is removed and the handle pullout is inserted in the switch ON position.

Abstract: An interlock between two main circuit breakers comprises a bracket mounted to the interior panel transversely of the panel and a sliding interlock member mounted on a forward portion of the bracket, which portion fits within the unmodified opening of a panelboard cover and fills the space within the opening between the two main circuit breakers. Padlock hasps may be provided on the interlock member to additionally lock either or both main circuit breakers in an OFF condition. Tabs on the bracket overlie forward facing surfaces of the main circuit breakers to block removal of the main circuit breakers while the bracket is installed.

Abstract: A molded case circuit breaker having an operating mechanism including a collapsible toggle linkage, an operating handle and a movable frame. The collapsible toggle linkage includes a rectangular cross section knee pin non-rotatably held within an open rectangular slot in an upper link of the linkage. The operating handle pivots about a first pivot point when moving between ON, OFF and TRIPPED positions. The operating handle pivots about a second pivot point when moving to a RESET position thereby reducing the lateral force component of the operating springs of the operating mechanism for reliable return of the handle to the OFF position. Also, bifurcated movable contact fingers are provided for pivotal movement about a fixed pin to break contact welds and a trapezoidal cross section shaft interconnects the movable contact fingers.

Abstract: A molded case circuit breaker having an operating mechanism including a collapsible toggle linkage, an operating handle and a movable frame. The collapsible toggle linkage includes a rectangular cross section knee pin non-rotatably held within an open rectangular slot in an upper link of the linkage. The operating handle pivots about a first pivot point when moving between ON, OFF and TRIPPED positions. The operating handle pivots about a second pivot point when moving to a RESET position thereby reducing the lateral force component of the operating springs of the operating mechanism for reliable return of the handle to the OFF position. Also, bifurcated movable contact fingers are provided for pivotal movement about a fixed pin to break contact welds and a trapezoidal cross section shaft interconnects the movable contact fingers.

Abstract: A plunger operated switch has a pair of movable contacts on a movable contact carrier bridged by a secondary contact supported on a pushbutton operator member which is biased apart from the contact carrier. Depression of the pushbutton operator for the plunger assembly moves the primary movable contacts into bridging engagement with the stationary contacts through the secondary contact member. In the event the primary movable contacts weld to the stationary contacts and an operating force is removed from the plunger operator, a spring biases the secondary contact away from the primary movable contacts to open the bridging relationship therebetween and open the circuit controlled by the switch. A pair of normally closed contacts are arranged for operation by the pushbutton operator so that the contacts open before the main contacts close and close after the main contacts open, rendering them particularly suitable for use as dynamic braking contacts in a motor control application.

Abstract: Molded case circuit breaker having collapsible toggle linkage with rectangular cross section knee pin non-rotatably held within open rectangular slots in upper link, bifurcated movable contact fingers loosely guided for pivotal movement about fixed pin to break contact welds, helical compression springs biasing bifurcations against faces of a stationary connector, trapezoidal cross section shaft biasing shaft against a fixed corner of clamping strap and frame, increasing clamping force and increasing tool clearance, operating handle which changes pivot point moving to RESET position, reducing lateral force component of operating springs for reliable return of handle to OFF position, dual stops for movable contact fingers to spread impact forces along fingers, greater contact separation in poles not containing operating mechanism, slot motor laminations providing metal reinforcement to separate arc chamber housing which is cooperatively interlocked with base to distribute structural strength, terminal cover wi

Abstract: A molded generally planar U-shaped plastic member has a pair of lateral projections on one leg and a single lateral projection at a distal end of the other leg, which projections are received in recesses in mutually facing surfaces of a raised escutcheon rib surrounding a handle opening to locate the base of the U-shaped member in the path of the handle, blocking movement of the handle. A notch in the distal end of the leg having the single lateral projection receives a flat-bladed tool which is twistable against the escutcheon rib surface to deflect the leg inward and projection free of the respective recess to release the handle block. The recesses are symmetrically arranged to permit the handle block to be installed to block the handle ON or OFF as desired.

Abstract: A plastic load center box economically provided by duplicate molded end sections joined by an intermediate section of uniform cross-section which is readily provided in selected lengths in either molded or extruded form. End walls receive metal inserts electrically interconnected to provide grounding when attached to grounded conduit, or plastic inserts where the load center application does not require grounded conduit. Molded end sections have formed knockouts and wire clamping tabs. A metal cover for the box is grounded to the metal inserts or to the interconnection. Additional plastic inserts in the end walls provide forwardly open pockets in which cable may be laid, and closing inserts overlying the pockets to grip the cable and retain it in the pockets.

Abstract: Molded case circuit breaker having collapsible toggle linkage with rectangular cross section knee pin non-rotatably held within open rectangular slots in upper link, bifurcated movable contact fingers loosely guided for pivotal movement about fixed pin to break contact welds, helical compression springs biasing bifurcations against faces of a stationary connector, trapezoidal cross section shaft biasing shaft against a fixed corner of clamping strap and frame, increasing clamping force and increasing tool clearance, operating handle which changes pivot point moving to RESET position, reducing lateral force component of operating springs for reliable return of handle to OFF position, dual stops for movable contact fingers to spread impact forces along fingers, greater contact separation in poles not containing operating mechanism, slot motor laminations providing metal reinforcement to separate arc chamber housing which is cooperatively interlocked with base to distribute structural strength, terminal cover wi

Abstract: Molded case circuit breaker having collapsible toggle linkage with rectangular cross section knee pin non-rotatably held within open rectangular slots in upper link, bifurcated movable contact fingers loosely guided for pivotal movement about fixed pin to break contact welds, helical compression springs biasing bifurcations against faces of a stationary connector, trapezoidal cross section shaft biasing shaft against a fixed corner of clamping strap and frame, increasing clamping force and increasing tool clearance, operating handle which changes pivot point moving to RESET position, reducing lateral force component of operating springs for reliable return of handle to OFF position, dual stops for movable contact fingers to spread impact forces along fingers, greater contact separation in poles not containing operating mechanism, slot motor laminations providing metal reinforcement to separate arc chamber housing which is cooperatively interlocked with base to distribute structural strength, terminal cover wi

Abstract: A circuit interrupter manually opens and closes its contacts by use of a manually rotatable handle which acts through a collapsible linkage rotatably connected to a crank extension of the handle and rotatably connected to a rotatably movable contact support. The rotatable contact support is urged away from closed contact position by a main spring and in moving from one contact position to the other the axis of the rotatable connection between the handle crank passes over a center line defined by the center of rotation of the handle and the rotatable connection between the linkage and the movable contact support providing a toggle action to hold the movable contact in selected open or closed position. Upon overload, the mechanism causes collapse of the collapsible linkage allowing the movable contact support to move and open the contacts.

Abstract: Molded case circuit breaker having collapsible toggle linkage with rectangular cross section knee pin non-rotatably held within open rectangular slots in upper link, bifurcated movable contact fingers loosely guided for pivotal movement about fixed pin to break contact welds, helical compression springs biasing bifurcations against faces of a stationary connector, trapezoidal cross section shaft biasing shaft against a fixed corner of clamping strap and frame, increasing clamping force and increasing tool clearance, operating handle which changes pivot point moving to RESET position, reducing lateral force component of operating springs for reliable return of handle to OFF position, dual stops for movable contact fingers to spread impact forces along fingers, greater contact separation in poles not containing operating mechanism, slot motor laminations providing metal reinforcement to separate arc chamber housing which is cooperatively interlocked with base to distribute structural strength, terminal cover wi

Abstract: Molded case circuit breaker having collapsible toggle linkage with rectangular cross section knee pin non-rotatably held within open rectangular slots in upper link, bifurcated movable contact fingers loosely guided for pivotal movement about fixed pin to break contact welds, helical compression springs biasing bifurcations against faces of a stationary connector, trapezoidal cross section shaft biasing shaft against a fixed corner of clamping strap and frame, increasing clamping force and increasing tool clearance, operating handle which changes pivot point moving to RESET position, reducing lateral force component of operating springs for reliable return of handle to OFF position, dual stops for movable contact fingers to spread impact forces along fingers, greater contact separation in poles not containing operating mechanism, slot motor laminations providing metal reinforcement to separate arc chamber housing which is cooperatively interlocked with base to distribute structural strength, terminal cover wi

Abstract: Light emitting diodes of a through beam photoelectric detector are positioned in a door hinged to a sensor body in which the photodetector diodes are located. The light emitting diodes and photodetector diodes are aligned to establish photoelectric sensors when the door is closed upon the body. A base provides a receptacle for attachment of the sensor, the base having a plug-in electrical terminal half for receiving the connector prongs of a second half of the connector carried by the body. The connector is symmetrical so that the sensor unit may be installed to the base in either of two operating positions spaced 180 degrees apart to enable the hinge to be located at either the right-hand or left-hand side of the sensor unit and of the stations to be sensed.

Abstract: A wire-wound bobbin serves as the core of a current transformer. A magnetic material flux path is disposed on the core that encircles the core coincident with the coils of the bobbin at least once and radially encircles the cross section of the core at lest once. The magnetic flux path comprises an assembly of distinct magnetic members positioned on the core and held in place by tape or the like.

Abstract: A neutral connector of a standard three-phase, three-wire panelboard is replaced by a specific multiple termination assembly having a limited number of terminations specifically adapted for connection to ground at the panelboard, for grounding the termination assembly to the panelboard enclosure, and for connecting the multiple termination assembly to the power conductor of the system grounded phase which is also connected to one pole of the main circuit breaker, main switch or main lug of the panelboard. Standard AIC rated three-pole circuit breakers or fusible switches are wired to three-phase loads in the branch circuits and connected to the three bus bars of the panelboard to connect the grounded phase to the load through the circuit breaker or switch, and to open all phases when operated.