Abstract: A sensor system is disclosed. The system comprises a sensor for sensing an input between a first, minimum sensor input value and a second, maximum sensor input value. The sensor generates a sensor output signal relative to the sensor input value. The sensor is subject to offset and gain errors. The system further includes a microprocessor having first and second output signals and a signal conditioner coupled between the sensor and the microprocessor. The signal conditioner generates a first signal conditioner signal when the sensor input value equals the minimum sensor input value and generates a maximum signal conditioner signal when the sensor input value equals the maximum sensor input value. The signal conditioner includes circuitry for minimizing the sensor offset error and circuitry for minimizing the sensor gain error.

Abstract: A method of calibrating the selectable trip points of an overload relay wherein a neural network is used in the calibration process. The calibration method involves precisely positioning an indicia comprised of a number of graduation marks or symbols each representing a particular trip point and having a range and spacing unique to the characteristics of an overload detection circuit of a particular overload relay. The indicia is calibrated with respect to predetermined positions of a trip point indicator and fixed with respect to the predetermined positions of the trip point indicator. The range and spacing of the indicia graduations is derived from the neural networks learned trip point values and from trip point values obtained from the particular overload relay being calibrated.

Abstract: An enclosure is for a solid state overload relay mechanism or other device. The enclosure includes a mounting plate (12) defining a pair of upwardly extending flanges (14). A housing includes a lower housing (18) and an upper housing. The mounting plate flanges (14) are received through slotted openings (22) defined by the lower housing (18) and define openings (26) for engaging a tab member (28) defined by the lower housing (18). Each tab member (28) is received within and engaged with a corresponding opening (26) defined by a flange (14). A constant pressure is maintained between the tab member (28) and the mounting plate flange opening (26) such that the relative position between the two is fixed. Mounting profiles are defined by the mounting plate (12) and extend away from the lower housing (18) for retrofitting an existing device. The upper and lower housings (18,20) are held in a conventional snap-fit manner.

Abstract: A current induction arrangement develops a power supply voltage and a measurement signal from current flowing in a circuit path so as to optimize both the energy developed in the power supply and the fidelity of the sinusoidal signal used to measure the waveform in the circuit path. The arrangement includes a capacitor accumulating current to develop a positive voltage with respect to common, a current transformer inducing current from the circuit path and providing an output having a positive induced-current signal component and a negative induced-current signal component. A rectifier circuit is arranged to receive the output from the current transformer, and to produce the positive induced current signal component at a positive output terminal and the negative induced current signal component at a negative output terminal. A first zener diode is connected to receive the positive induced-current signal component, and the circuit permits the positive induced-current signal to charge the capacitor.

Abstract: A calibration method for a potentiometer which provides indicia reflecting an accurate indication of actual electrical resistance throughout the resistive range of a particular potentiometer. The indicia includes a number of graduation marks or symbols having a range and spacing unique to the resistive characteristics of the particular potentiometer. The indicia is fixed with respect to a known location associated with the particular potentiometer. The range and spacing of the indicia graduations is derived from measured resistance values at predetermined locations along the resistive member of the particular potentiometer.

Abstract: Disclosed is a method for making a laminate having utility in an electrical inductive apparatus, which first comprises coating at least one side of a metal substrate with a solventless liquid resin system comprising an ultraviolet radiation curable acrylic or vinyl monomer and a heat reactive thermoset adhesive resin. The resin system on the coated metal substrate is then exposed to ultraviolet radiation to cure the ultraviolet radiation curable monomer. The resin system is now a tacky solid layer. The laminates so formed can be assembled into components for use in applications such as electric power transformers, ignition coils, generators, chokes, reactors, solenoids ballasts, motors and electronics, in which prior art laminates have been utilized. The assembled laminates are then exposed to sufficient heat to cure the heat reactive thermoset resin and adhere the laminate layers together.

Abstract: The present invention defines a convertible electrical contact. The convertible contact comprises two pair of movable contacts attached to an actuator which is supported by and enclosed within a housing. The actuator is biased to a first position and is slidably movable to a second position in response to a force applied to the actuator. The movable contacts are attached to the distal ends of a flexible member which is supported at its approximate midpoint by the actuator. The movable contacts are also movable between a first position and a second position as the actuator is moved. A pair of contact cavities are defined by the housing such that the one contact cavity lies on each side of the actuator and the flexible member and movable contacts are contained within the cavities. The housing defines a first pair of access apertures associated with the first position of the movable contacts and a second pair of access apertures associated with the second position of the movable contacts.

Abstract: A manually actuatable integrated contact module connecting to an output access module by means of a common communications link. The integrated contact module has an electrical contact, a logic circuit, a communications circuit and a communications terminal mounted on a common printed circuit board. The printed circuit board provides communication between the electrical contact and the logic circuit, between the logic circuit and the communications circuit, and between the communications circuit and the communications terminal. The printed circuit board is enclosed within a protective housing. A contact operator is slidably mounted with respect to the printed circuit board such that it is partially enclosed within the housing and movable between a first position and a second position.

Abstract: A modular circuit interrupter is arranged for interrupting current in a three-phase circuit path providing current from a three-phase source to a three-phase motor. The interrupter includes a contactor unit arranged to interrupt the circuit path in response to a trip command; a current inducer circuit for providing a current signal having a magnitude corresponding to the current in the circuit path; a fault detection circuit responsive to the current signal, for detecting and communicating power faults in the circuit path; and start and stop motor modules. Respective housings are provided for each of the contactor unit, the fault detection circuit, the start motor module and the stop motor module. A data/power communication bus provides a data communication link between each of the contactor unit, the fault detection circuit, the start motor module and the stop motor module.

Abstract: A method for laminating a magnetic core of a three-phase current transformer uses a continuous length of magnetic metal material and a mandrel having first, second, third, and fourth sets of pins mounted to a mandrel plate. The second and third pin sets are located adjacent one another, adjacent the respective first and fourth pin sets, and between the first and fourth pin sets. The third and fourth pin sets are movable between a retracted position within the mandrel plate and an extended position extending from the mandrel plate. The third and fourth pin sets are first positioned in the retracted position, and a first portion of the length of magnetic material is wound about the first and second pin sets to form the first phase section of the magnetic core. After moving the third pin set to the extended position, a second portion of the length of magnetic material is wound about the first and third pin sets to form the second phase section.

Abstract: An end feed connector for connecting a plurality of feed lines to a pre-bussed rigid conduit which has feed line connectors that fit in slots in an insulating housing. Within the housing, the slots communicate with conductive sleeves that are disposed in the pattern of the pre-bussed rigid conduit with which the end feed connector is intended to mate. Bus bars within the housing connect the feed line connectors to the sleeves.

Abstract: The present invention provides a low burden visual POWER ON indicator for a self-powered electrical circuit protection device. The visual indicator includes a current transformer for producing an induced current in direct proportion to the current supplied to an electrical device protected by the protection device. The induced current is summed and rectified. An energy accumulator stores a predetermined voltage required to operate the protection device. The stored voltage is controlled by an accumulation switch which in turn is controlled by a hysteresis control circuit. The hysteresis control circuit includes an operational amplifier which is biased by a stable reference voltage. When the voltage on the energy accumulator is equal to the stable reference voltage the operational amplifier produces a HIGH output signal. When the voltage on the energy accumulator is less than the stable reference voltage the operational amplifier produces a LOW output signal.

Abstract: A solid state overload relay utilizes an apparatus that converts the current of a polyphase electrical load to a voltage signal approximately proportional to the RMS current of the load. In addition to providing the overload function, the voltage signal is used to provide an improved phase current unbalance protection. Conventional current transformers sense the current flow in each phase of the load. The current waveform for each phase is converted to a voltage by rectification and the peak value and the average value of the resultant voltage is determined. A summing circuit combines the two values at a predetermined ratio to create a DC voltage that is approximately equal to the rms value of the input phase current. A combination of the approximation circuit with a time integrating circuit and a level detecting circuit produces a low cost solid state overload relay in one embodiment of the invention.

Abstract: A circuit for detecting phase imbalance in a three phase electrical system. The circuit includes a three phase current transformer or three separate current transformers for monitoring the current flowing in each phase of a three phase electrical system. The current transformers provide an induced current proportional to the monitored current. The induced current passes through a full-wave bridge rectifier which produces a voltage output proportional to the induced current. This voltage signal is passed to a two pole Sallen-Key filter which allows a desired signal having a particular frequency range to pass through and blocks the passage of an undesired signal having a particular frequency range. A scaling circuit then receives a portion of the desired signal and produces a scaled average signal which is of a preselected magnitude lower than the desired signal.

Abstract: A solid state overload relay mechanism designed for minimizing the forces required to open an electrical contact associated therewith in the event of a current overload in a protected circuit, and further designed for overcoming residual magnetism in a solenoid initiating the opening of the contact. The contact includes a pair of stationary contacts supported by a base and a pair of movable contact supported by a contact carrier. A latch defines a notch which is normally engaged with a lever. When so engaged, the contact carrier is positioned such that the movable contacts are in contact with the stationary contacts. When the lever becomes disengaged from the latch, the contact carrier is moved and contact between the movable contacts and stationary contacts is broken. The latch is provided with a counterbalance weight to aid in minimizing the force required to return the latch to its original position after the mechanism is tripped.

Abstract: A code reading device for use in an industrial flexible automation track system is disclosed wherein a code reading device reads codes stored in a code storing device attached to a work piece carrier. The code reading device includes a multiple sensor sensing head in which any one or all of the enclosed sensors may be easily replaced. Each sensor is slidably received within a pocket in the sensing head and provided with a plug-on electrical connector such that it may be easily replaced should a failure occur or should a different type of sensor be required.

Abstract: A sectionalized electrical distribution feeder system for carrying electrical power from a source point to a use point or a distribution point. Each section of the distribution system includes a substantially cylindrical enclosure capable of being easily cut with a hand saw. The enclosure also provides support and protection from physical damage to a plurality of electrical conductors which are disposed within the enclosure. The conductors are held firmly in place by a number of electrically insulating supports which snugly fit inside the enclosure. Each conductor can be easily cut with a metal cutting hand saw, and is enclosed in an electrically insulating sheath which can be removed from a newly cut end to provide a contact surface. A joint connecting member is provided for electrically connecting the conductors of adjacent sections of the electrical distribution feeder system. A joint cover connects the two adjacent enclosures together and provides additional protection for the joint connecting member.

Abstract: An insulation stripping tool of the present invention removes insulation from the free ends of a substantially rigid electrical conductor. The tool has a barrel at one end and a handle at the other end. The barrel is generally tubular in shape and longitudinally receives a free end of the substantially rigid insulated electrical conductor. An insulation cutter is captivated within the barrel for cutting off a predetermined length of insulation from the free end of the conductor.

Abstract: The low dissipation compact circuit breaker of the present invention selectively conducts breaker current in a circuit to be protected. The compact circuit breaker is in an enclosure surrounding at least a stationary contact and a moveable contact. This moving contact selectively assumes one of two bistable states, a contiguous closed state or a noncontiguous open state. A rotary operator including rotary members and a contact lever train selectively causes the stationary contact and the moveable contact to assume either a closed or an open state. A single solenoid for sensing breaker current in each phase causes the rotary operator to move the contacts from a closed state to an open state. Additionally, the solenoid for a faulted phase directly acts on a solenoid bell crank to cause the contact to begin to assume an open state in a trip operation, if breaker current reaches a preselected trip value in the faulted phase.

Abstract: The motor controller of the present invention includes a power bus, an insulated gate bipolar power transistor and a control circuit. The direct current power bus provided a source and sink of current to be conducted to and from a controller motor. The insulated gate bipolar power transistor selectively conducts transistor current to and from the motor. The control circuit among other things determines power gate timing of the power transistor and the manner in which the insulated gate bipolar transistor conducts and ceases to conduct transistor current to or from the motor.