Abstract: A molded case circuit breaker is provided with a line conductor having a U-shaped slot defining a pair of depending leg conducting portions and a peninsula portion. The U-shaped slot is adapted to receive a slot motor and also causes the current of the peninsula portion to flow in a direction opposite the direction of current flow in the movable contact arm to cause the contacts to be blown open during relatively high level overcurrent conditions. The peninsula portion is tapered outwardly, toward the base of the peninsula to increase the overall cross-sectional area of the conductor to minimize temperature rise. The tapered peninsula portion still allows a slot motor to be received in the U-shaped slot.

Abstract: A molded case circuit breaker is provided with a toggle assembly having upper toggle links secured to U-shaped members of a cradle assembly with a hardened pin. The pin is formed with annular grooves disposed intermediate the ends forming a center sleeve portion and stop surfaces at each end. The center sleeve portion is slightly longer than the width of the U-shaped member to provide spacing between the upper toggle links and the U-shaped members. The upper toggle links are formed with U-shaped slots disposed at one end which are received in the annular grooves. The U-shaped slots formed at the other end of the toggle links are offset from the longitudinal axis of the toggle links and receive the pin. The upper toggle links are assembled such the offset U-shaped grooves are disposed in opposite directions to help secure the the assembly together.

Abstract: Apparatus which is mechanically connected to and out of direct contact of the handle arm of an electrical circuit breaker to prevent the operating lever of the circuit breaker from being moved to the off position when the contacts of the circuit breaker are closed, due to a weldment of the contacts or obstruction of the contact arm carriers. In particular, a two part toggle mechanism is provided for opening and closing contacts in conjuction with the movement of the operating lever. The lower toggle link has a protrusion thereon which abuts against the rotatable crossbar mechanism which carries the contact arm of the moveable contacts if the contacts have not separated as the operating lever is moved from the closed to open position. The abutments, however, will rotate free of the crossbar if the contact arm moves in conjunction with the movement of the crossbar as the lever is moved from the open to closed position.

Abstract: A draw out interlock comprises an elongated interlock member which is coupled to the manual trip mechanism of a circuit breaker. The interlock member is springed bias to an extended position where it projects through the back wall of the circuit, but is retained in a retracted position by the surface against which the circuit breaker is mounted. As the circuit breaker is removed from the mounting surface, the interlock member extends actuating the manual trip mechanism and interrupting current before the circuit breaker becomes disconnected from the protected conductor to prevent arcing at the disconnects.

Abstract: A circuit breaker is disclosed having a movable magnetic core provided in the magnetic trip assembly thereof adapted to lower the current levels at which the magnetic trip mechanism will operate. The magnetic trip assembly also includes a pivotally connected armature, a current carrying conductor, a fixed magnetic yoke and a latchable operating mechanism. A primary air gap exists between the armature and the fixed yoke. The movable core is designed to move into an extended position which reduces the primary air gap which in turn increases magnetic flux coupling which allows the magnetic force required for the armature to pivotally rotate to unlatch the operating mechanism and thereby trip the circuit breaker to be generated at a lower current level. This reduction in current is the desired effect of the new design.

Abstract: A multipurpose combination barrier and auxiliary current transformer board is provided for a circuit breaker. The board is located at the rear of the circuit breaker housing to close an open portion of the housing and act as a barrier to prevent contact with internal circuit breaker components. Vent holes, provided in the bottom portion of the board, allow heat generated within the circuit breaker to be exhausted to the atmosphere. The top portion of the board serves as a mounting plate for the auxiliary current transformers. The top portion of the board is formed from a printed circuit board having an electric circuit disposed thereon for the connections between the main current transformers, auxiliary transformers and the electronic trip unit. Connectors are provided on the printed circuit board adjacent each auxiliary current transformer to connect the main current transformers to the printed circuit.

Abstract: A grounding switch device for a metal-clad switchgear is adapted to be inserted into a standard circuit breaker cell allows the bus and line conductors within the switchgear assembly to be grounded for maintenance. A plurality of fixed and selectable test ports are provided to facilitate various electrical tests. The ground switch device is disposed on a frame and contains a ground contact assembly for providing sliding contact between the ground switch device and the ground bus within the circuit breaker cell. The ground contact assembly is in electrical contact with a movable contact. The movable contact is adapted to engage a stationary contact mounted on a mounting plate, attached to the frame by way of an insulator. A selector switch assembly connects the stationary contact to either the upper bus terminals or line terminals in the metal-clad switchgear assembly. The contact portion of the movable contact is U-shaped having two spaced-apart blades.

Abstract: A circuit breaker having a trip mechanism comprising a primary armature which is attracted toward a bimetal by magnetic flux produced by a predetermined overcurrent flowing through the bimetal to unlatch an operating mechanism and open electrical contacts, includes a pivoted supplemental armature which is also attracted toward the bimetal by the overcurrent and which bears against and urges the primary armature toward the bimetal to thereby reduce the predetermined overcurrent at which the breaker opens the electrical contacts. The supplemental armature comprises a flat strip of magnetically permeable material which is bent at one end to form a hook which merely drops into a recess in the breaker housing. Integral flanges on the strip form a magnetic yoke which concentrates the magnetic flux to increase the sensitivity of the magnetic trip function.

Abstract: A circuit breaker auxiliary switch structure characterized by a contact arm carrying a first contact movable between open and closed positions with a second contact. An auxiliary switch is disposed in the path of movement of the contact arm and operable to open or close an auxiliary circuit associated with a circuit breaker.

Abstract: Apparatus for adjusting the calibration of a thermal trip unit which is to be used in conjunction with an electrical circuit breaker. A rotatable knob is provided which adjusts the trip unit to between one hundred percent of the rating of the circuit breaker and some value which is less than one hundred percent. An adjustable stop screw is provided to engage the rotatable knob when the knob is rotated to adjust the calibration of the trip unit to the desired value which is less than one hundred percent of the rating of the breaker. The adjustable stop screw thereby limits travel of the adjustable knob between only one hundred percent of the rating of the circuit breaker and the desired value which is less than one hundred percent.

Abstract: An electronically controlled lighting panelboard characterized by a power line panelboard having a plurality of remotely controlled circuit breakers for opening and closing circuits to corresponding loads. Each circuit breaker is interconnected to an interface which in turn is connected by a multi-conductor cable to an electronic controller or computer.

Abstract: An electronic controller, connected to a digital communication network, is responsive to commands from a master controller to control solenoid operated circuit breakers. The electronic controller also determines the status of all circuit breakers and reports back to the master controller to verify that the command from the master controller was executed and to provide historical data regarding the status of the circuit breakers. The electronic controller is synchronized to the same alternating current (AC) power source as the circuit breakers to control the operation of the respective circuit breakers to minimize electromagnetic interference (EMI) caused by the switching of the circuit breakers. The electronic controller further controls the operation of the circuit breakers to reduce the duty cycle of the power supply for the circuit breaker solenoids.

Abstract: A low cost, multipurpose digital IC is used as the basic building block in establishing a network communication system over a desired communication link. The digital IC can function as an addressable microcomputer interface between the network line and a remotely located microcomputer which may, for example, comprise any microprocessor based controlled product. In such mode, the digital IC's function is to take data from the network and pass it on to the remotely located microcomputer upon command from the central controller and to transmit data from the microcomputer to the central controller. The digital IC may also function as a nonaddressable microcomputer interface between the central or master controller and the network line. In such case the digital IC's function is to continuously take data from the central controller and place it on the network and take data from the network and pass it back to the central controller.

Abstract: A circuit breaker with over-temperature protector and low error I.sup.2 t calculator is provided. The over-temperature protector includes a fixed current source which provides current to a resistive element to produce a voltage which thereacross which increases with a positive temperature coefficient as the surrounding temperature increases. The resistor is connected to the base-to-emitter circuit of a transistor. The base-to-emitter circuit has a minimum firing voltage which decreases with an increase in ambient temperature. The value of the resistive element, the amount of current provided by the fixed current source and the transistor base-to-emitter minimum firing voltage are chosen to cause a circuit breaker to be actuated. There is also provided an active memory device which is utilized to discharge a capacitor with a time constant which approximates the heat dissipating time constant associated with a conductor to be protected by the circuit breaker in question.

Abstract: A gap monitor for rolls of a continuous casting machine characterized by sets of rolls disposed in opposed pairs separated by spaced gaps and defining a path of travel for a workpiece, each roll comprising aligned roll segments, a roll gap monitor including a housing having one side retractably movable from the housing to contact rolls so that the other side of the housing also contacts the corresponding rolls. The one side is coextensive with the housing and is spring biased outwardly to contact the aligned roll segments. The monitor also comprises a gap sensor extending between opposite sides of the housing and having opposite ends engageable with the opposite pairs of rolls successively as the monitor moves through the path of travel. Transducer means are operatively connected to the gap sensor for transmitting signals representative of measurements of the gaps of each pair of rolls.

Abstract: An alternating current electromagnet with a magnetic core assembly is provided with a unique design for a sideplate. The sideplate has a slot with a lateral opening. In assembling the sideplate onto the side of the magnetic core, the slot receives a shading coil. A portion of the sideplate forming the slot extends across a channel formed in a pole face of the core to lock the shading coil into the channel along the sides of the core. The sideplate is formed in a C-configuration and interconnects two L-shape cores arranged in a C-configuration with a gap existing between the confronting faces of the lower legs of the cores.

Abstract: A molded case circuit breaker is provided with side plates having twist tabs extending downwardly from a bottom edge for fastening the side plates to the circuit breaker base. Spin plates with slots are carried by the base for receiving the twist tabs. The twist tabs are formed with a shank portion, a tapered portion and a head portion. The tapered portion defines a sloped surface which contacts the slot in the spin plate. When the twist tab is twisted, the shank is shortened drawing a wider portion of the sloped surface into the engagement with the slot to secure the side plate to the base.

Abstract: An automatic transfer switch with microprocessor and a display which includes clusters or combinations of display cells. There may, for example, be sixteen display cells for a 16-word display. The display cells are driven by two serially connected shift registers, the input of the first of which is interconnected with the microprocessor. Sixteen digital words are supplied in sequence to the shift registers. One portion of the digital word is then provided in parallel to each of the display cells simultaneously but another portion of the word is supplied to an encoding device which tells which of the sixteen display cells will display that word. One 16 word message requires sixteen reiterations performed at high speed so that it appears that all sixteen display devices are actuated simultaneously to display one multi-word message.

Abstract: An electromagnetic contactor or motor controller is taught in which an energy efficient bounceless contact closing operation is utilized. An electromagnetic closing coil voltage is sensed by the contactor control system and compared against a memory menu of stored delay angles for a wide range of sensed voltages. The delay angles are applied to the conduction interval of a triac or similar gated device which is connected in series with the coil for controlling current flow therethrough. Depending upon the voltage sensed the amount of current flowing through the coil on a half cycle by half cycle basis is varied by the control system.

Abstract: A laminated contact assembly is formed from a number of individual contact assemblies. Each individual contact assembly includes a contact arm portion, which carries a movable main or arcing contact and a stationary conductor portion. A flexible shunt is used to connect the contact arm portion to the stationary conductor portion. Intermediate individual contact assemblies are provided with T-shaped slots for receiving square-headed fasteners. These square-headed fasteners are captured by adjacent assemblies once the laminated contact assembly is complete. By providing such an arrangement, the need to drill and tap holes in the base of the laminated contact arm assembly is obviated. Since all of the individual contact arm assemblies are fastened together, the possibility of the square-headed fasteners disposed in T-shaped slots in intermediate individual contact arm assemblies is greatly reduced.