Abstract: A fuse cutout for connection to a power source includes a mounting having upper and lower support members extending from opposing ends of the mounting. The upper support member includes a first contact having opposing first and second end portions, with the first end portion being attached to the upper support member, and a dome portion disposed between the first and second end portions. The dome portion includes opposing first and second dome surfaces and a first ridge extending along the second dome surface. A holder member is fixedly attached to the lower support member of the mounting. A pivot member is received in the holder member at a first pivot point, the pivot member being movable between first and second positions. A fuseholder is movable between closed and open positions and has upper and lower ends. The lower end is pivotally coupled to the pivot member at a second pivot point.

Abstract: Methods and apparatus for identifying in real time an operating condition of an in-service electrical device which draws a power load by monitoring spectral content of the power signature and associating spectral components with device operating conditions. In the preferred embodiment, motor (12) power line current signature is sampled by data conditioning sampler (18). Preprocessor (30) spectrally separates the current signature into plural frequency domain components having respective frequency and magnitude values. Spectral characteristic component selector filter (40) selects for analysis at least one specific spectral component by referencing a base of stored knowledge of operational characteristics of the motor. A neural network (50) associates without supervision the selected detected spectral component with an operating condition of the motor (12). The base of stored knowledge is updated with new operating condition associations which have been made during real-time monitoring.

Abstract: An apparatus for thermal protection of an electric motor is provided, including a monitoring device for generating a signal representative of the current in a conductor supplying electrical power to the electric motor. A control circuit processes the current signal and utilizes the processed signal and motor thermal parameters, including the thermal resistance and thermal capacitance of the rotor, to generate signals representative of the temperature of at least the rotor. A comparator circuit, which may be part of the control circuit, compares the temperature signals to reference maximum temperature signals and produces a control signal when the temperature signals and reference signals satisfy a predetermined relationship. The control signal may be applied to a contactor to interrupt current to the motor. A method for thermal protection of an electric motor is also provided, including thermal modeling of the rotor temperature.

Abstract: A motor control unit for protecting a motor against overload, short circuit and ground fault currents. The unit monitors the currents in each phase of the motor to provide values representative of each phase current. The unit also includes a contactor for opening and closing each phase, wherein the unit controls the contactor based upon the values representative of the phase currents. The contactor is opened where the phase currents exceed limits which indicate that either an overload, short circuit or ground fault situation exists at the motor. A magnetic trip circuit breaker can also be provided to operate in cooperation with the unit to provide instantaneous trip protection for current levels which are relatively high in relation to those for which the contactor is rated.

Abstract: A motor control unit for protecting a motor against ground fault currents. The unit monitors the currents in each phase of the motor to provide values representative of each phase current. The unit also includes a contactor for opening and closing each phase, wherein the unit controls the contactor based upon the values representative of the phase currents. The contactor is opened when a ground fault situation exists at the motor.

Abstract: A microcomputer-based device that performs the functions of motor starting and overload protection. The starter function is customized for a particular application by storing program steps representing the input command and output control logic peculiar to a given motor in a programmable, non-volatile memory cell. Each set of program steps, which the microcomputer executes, compose an expandable library of such sets representing the different motor circuit applications available for configuring a starter to match its particular application. A configuration can be changed by simply loading into memory the appropriate set of program steps from the library and changing the labels of the inputs and outputs to match the new application.

Abstract: An apparatus for starting and controlling a motor. The apparatus includes means for monitoring the load current values in each phase of a motor. These means can include an apparatus such as a current transformer. The apparatus utilizes a circuit for modeling a motor and estimating the temperatures of the motor's windings and housing. THe circuit preferably is defined by a programmed microprocessor. The estimated temperatures are based on the load current values and time. These estimated temperatures are then compared to allowable limits and, based on the comparison, the motor is either stopped or allowed to run.

Abstract: A bus bar stab and insulator assembly for a motor controller has a two-piece housing and a three-piece stab finger clip. The housing base has a number of partitions which define pathways for the stab fingers. The housing cover is slidably mateable with the base and has a tab for receiving a self tapping screw. The stab fingers extend from the housing for making contact with bus bars. The stab finger clip has two fingers with interlocking tabs secured together with a screw which also connects one or more connector cables to the clip. The fingers are constructed of copper alloy and do not require the use of springs.

Abstract: A bus bar stab insulator shroud cooperates with a bus bar stab housing to insulate and protect the stab fingers. The shroud includes an insulative member which has first and second side members connected by a central member which has first and second openings of a size sufficient for receiving stabs of a bus bar stab.

Abstract: A load break switch and interlock assembly is housed in a cabinet with a door. The switch assembly is oriented 90.degree. from a normal position along the backwall of the cabinet and is located on a sidewall. The switch handle protrudes through the front of the cabinet. The handle is horizontally oriented to interfere with the door when the switch is closed thereby preventing the door from being opened. When the switch is open, the handle is vertically oriented and does not interfere with the door.

Abstract: A shutter mechanism is provided for a motor control center of the type having a backwall with a stab opening for receiving a stab connector for making electrical contact with bus bars which are behind the panel. The shutter consists of two pieces, a stationary member which has a central opening and a vertical slit opening into the central opening and a movable member which has a guide thereon and is positioned between the motor control center and the stationary member with the guide extending through the slit and vertically movable therein. The stationary member is fastened to the motor control center with the central opening overlaying the stab opening. The movable member moves from a closed position to an open position and then from the open position to the closed position under the force of gravity alone without the use of springs.

Abstract: A solenoid actuated mechanical interlock is provided for the draw-out type circuit breaker mechanism of a motor control center. The interlock is formed by the plunger of the solenoid engaging a slot in the bellcrank mechanism of the draw-out unit. Electric circuitry controls operation of the solenoid so that the plunger is controllably extended and retracted to prevent or permit operation of the bell crank under certain conditions.

Abstract: An operator is provided for a molded-case circuit breaker of the type in a motor controller where the circuit breaker is removably mounted on a pan brace which is held in place by a pan latch. The operator mounts on the breaker for opening and closing the breaker and for providing three interlocks. One interlock prevents withdrawal or insertion of the breaker with the operator handle in the "on" position. A second interlock prohibits closing or opening the control door except when the handle is off and a third interlock locks the operator handle in "off" position.

Abstract: A warning feature for a high voltage controller or the like. A lamp is mounted on the controller cabinet, and connected to an interlock circuit so as to be illuminated whenever line voltage is being supplied to a contactor assembly, regardless of the open or closed status of the contactor itself.

Abstract: A motor control center of the high voltage type which includes a set of three vertically-disposed cubicles. The two lower cubicles house a pair of contactor assemblies, the lowermost contactor assembly being longer than the upper one. The cubicle enclosing the upper contactor is provided with a partition behind which is a compartment containing vertical bus bars. The lowermost cubicle extends beneath this compartment so that the bus bars drop directly down to engage a set of connectors which are also engaged by the lowermost contactor assembly.

Abstract: An improved drawout carriage assembly for the contactor of a high voltage controller. The controller carriage is fabricated from a pair of sheet metal sides, interconnected at their lower edge by formed sheet metal cross members. The upper portions of the sides are comprised of planar sheets of insulating material. A series of insulative cross members are bolted between the opposed faces of the carriage side pieces and locate elements of the contactor mechanism.

Abstract: A cabinet enclosing high voltage electrical apparatus is formed of a deformable, alignable framework made of structural steel or the like, and comprises at least one compartment for receiving a contactor carriage assembly. A rigid subchassis is separately constructed and mounted within each cubicle. The subchassis forms a high-integrity structure which supports and engages the contactor carriage, and maintains alignment of interengaging parts despite distortions of the cabinet framework.

Abstract: An improved mechanism for racking a contactor mechanism within an enclosure. The mechanism is urged into a fully-engaged position by an arm extending from a rotatable cross shaft which in turn is operated by a pair of complementary four-bar linkages. The first linkage in effect consists of a handle, connecting rod and bellcrank, the second consisting of the bellcrank and another arm, affixed to the cross shaft. An improved spring-loaded detent arm assists in holding the handle in the "racked on" position and a pivoted interlock engages the bellcrank in two positions.

Abstract: An electrical stab assembly for connection to vertical bus bars in an electric control center and which includes connector jaws floatably mounted in an insulated molded base. The floatable mounting permits the connector jaws to move with the bus bars to which they are connected, as the bus bars move due to thermal expansion, thus eliminating relative motion between the bus bars and the jaws connected thereto which is one of the basic causes of failure of stab type connector jaws.