Abstract: A tap-off box includes a latch that automatically secures the tap-off box to a busway upon insertion of a mast into the busway. The latch is in the form of a single spring-loaded member that latches onto a rail as the masthead is pushed into the busway. A push button actuated camming member pushes the latch away from the rail to enable the masthead to be withdrawn from the busway. The push button and camming member are independent of the mechanism that extends and retracts the contacts while the masthead is inserted and latched into the busway. The tap-off box may also include non-contact current monitoring sensors with voltage sensing inserts that an auxiliary breaker switch in applications other than a tap-off box, and an infrared emitting faceplate that can be adapted for monitoring a variety of breakers from outside the tap-off box.

Abstract: A splice connector for a busway system utilizes individual connectors made of a conductive material and having a u-shaped cross-section that fit over ends of a pair of busbars to be connected to each other, and within which are mounted multi-contact louvers that extend the length of the connectors to establish a low impedance electrical connection between the connector and the respective busbars. The louvers are secured in place by a dovetail groove that retains the louvers within the connectors and causes the individual contact sections of the louvers to bow outwardly so as to press against the busbars when the connector is fitted over the busbars. The connectors are snapped into insulative housing halves or sections that align the connectors with the busbars, and that provide isolation between horizontally aligned pairs of connectors.

Abstract: A busway splice connector can include a first connector and a second connector. Each of the first connector and the second connector can define a busbar volume for receiving a portion of two busbars. The busway splice connector can also include a first housing that defines a first compartment for receiving the first connector. The busway splice connector can also include a second housing that defines a second compartment for receiving the second connector. The busway splice connector can also include an insulator configured to be positioned between the first housing and the second housing and to insulate the first connector from the second connector when the busway splice connector is assembled.

Abstract: An MMS sensor assembly includes a U-shaped bottom housing that forms a recess in which is received a conductor whose current is to be sensed and a top housing arranged to be removably latched to the bottom housing. At least one magnetic field sensor is situated within the top housing, such the magnetic field sensor is positioned adjacent the conductor when the top housing is latched to the bottom housing, and is removable from the sensor assembly for repair or replacement. Circuitry connected to the magnetic field sensor includes a data storage device to store correction/compensation tables and/or equations for self-calibration or correction of the sensor.

Abstract: A splice connector for a busway system utilizes individual connectors made of a conductive material and having a u-shaped cross-section that fit over ends of a pair of busbars to be connected to each other, and within which are mounted multi-contact louvers that extend the length of the connectors to establish a low impedance electrical connection between the connector and the respective busbars. The louvers are secured in place by a dovetail groove that retains the louvers within the connectors and causes the individual contact sections of the louvers to bow outwardly so as to press against the busbars when the connector is fitted over the busbars. The connectors are snapped into insulative housing halves or sections that align the connectors with the busbars, and that provide isolation between horizontally aligned pairs of connectors.

Abstract: A DC power supply apparatus and method of supplying DC power for mission critical applications utilizes multiple power circuits in one unit, the power circuits being optimizable for efficiency as the load increases or decreases. The individual power supplies may use a multiphase topology within the power circuits, with logic phase shifts between multiphase, and two types of power management circuits arranged in parallel, or an equivalent controller, for implementing: (a) a variable linear or variable exponential precision droop algorithm, and (b) a “virtual bus” or current averaging/active current sharing circuit, the current sharing being provided by a low bandwidth communications link between droop controllers in each of the power circuits.

Abstract: An electrical power distribution system that can provide power to load equipment at any point along its length includes two main components: a power track housing assembly with current carrying conductors that can be mounted to the wall, ceiling or under the floor, and a plug-in power tap. The power track housing assembly includes a housing, insulators, and two or multiple conductors. In order to increase the housing assembly length, the housing assembly is preferably arranged such that multiple housing assemblies can be spliced together using cam operated splicing assemblies that form straight, “90 degree” and/or “T” splices to configure the system to match the equipment arrangement, and that allow all conductors in respective housing assemblies to be connected to each other simultaneously. The plug-in power taps also employ a system such as a shaft-cam mechanism that allows the assemblies to be electrically connected to all phase conductors within the power track housing assembly simultaneously.

Abstract: A method and device for connecting a load to an AC power source is arranged to ensure that the volt-second ratings of magnetic devices in the load are not exceeded, in order to limit in-rush currents resulting from saturation of the magnetic devices. In the case where the load is being disconnected from a first AC source and connected to a second AC source, the volt-seconds of the load can be measured and/or calculated during disconnect, in order to delay connection of the load to the second AC source by an amount sufficient to prevent saturation of magnetic devices and thereby ensure volt-second synchronization of the sources.

Abstract: A branch circuit monitor includes a plurality of non-contact current sensors arranged to sense current on each of a plurality of branch circuits, the non-contact current sensors being connected to a common digital signal processor (DSP) module having as inputs the outputs of the current sensors and also voltage inputs from each power source. The digital signal processor is arranged to calculate not only overall energy consumption, but also RMS voltage, RMS current, power factor, real power, and/or apparent power for each branch circuit. Preferably, the non-contact current sensors are in the form of miniature non-contact Rogowski coils or induction transducers. Data from the digital signal processor may be made available via communications protocols such as Modbus RTU or RS232/RS485/422, to any number of remote sites. The individual branch circuit monitors can be wired in a daisy chain or star network configuration and even connected to the Internet via an appropriate interface device.

Abstract: A circuit for correcting perturbations in a power system signal operating at a system line frequency includes a capacitor for drawing a capacitive current and a first inductor for drawing an inductive current substantially equal in amplitude and substantially one hundred eighty degrees out of phase with the capacitive current. The first inductor is connected in parallel with the capacitor to form a storage module for storing energy therein wherein the storage module is tuned to resonate at the system line frequency and wherein the storage module is connected in parallel across the load. A second inductor connected in series between a power source and the load isolates the power source from the load while a second capacitor in series with the second inductor, which together are tuned to resonate at the system line frequency, prevents voltage drop across the second inductor with linear loads.

Abstract: A harmonic current filtering transformer includes a three-phase input winding and at least two wye-connected three-phase output windings. Windings for each of the phases includes an in-phase coil connected between a common neutral and vector coils for each of the other two phases, the output windings thereby being phase shifted relative to each other by an amount which causes harmonic currents generated by a non-linear load to magnetically cancel in the transformer core. The harmonic current filtering transformer may be used as part of a harmonic cancelling power system which includes multiple linear and nonlinear loads, and protective devices, switches, filters and other components on both the input and output sides of the transformer as in a conventional power system since the harmonic cancelling transformer does not require additional secondary windings or other electrical components previously thought necessary to achieve harmonic cancellation.

Abstract: A harmonic current filtering transformer includes a three-phase input winding and at least two wye-connected three-phase output windings. The output windings are phase shifted relative to each other by an amount which causes harmonic currents generated by a non-linear load to magnetically cancel in the transformer core.

Abstract: A harmonic current filtering transformer includes a three-phase input winding and at least two wye-connected three-phase output windings. The output windings are phase shifted relative to each other by an amount which causes harmonic currents generated by a non-linear load to magnetically cancel in the transformer core.

Abstract: A microprocessorized thermal protection system and accompanying method measures input voltage and current of an induction motor and derives therefrom continuously updated estimates of the slip dependent rotor resistance during acceleration of the motor. The measurements and calculations of the varying rotor resistance enable determination of the heat generated within the motor based on a thermal model thereof. Phase shift distortions induced by the measurement system are accounted for by determining the value of the stator resistance at start up. In addition, during a brief period following start up, sampling of the voltage/current inputs is suspended to avoid the effects of the initially occurring DC-offset resulting from the application of the voltage input to the inductive motor load.

Abstract: A voltage regulator for AC single phase and three phase systems. An output voltage is controlled by controlling a preset stepped addition to or subtraction from the input voltage. The controlled addition or subtraction is performed by a series injection transformer whose secondary is in series with the input voltage and whose primary is controlled by a microprocessor based switch matrix. The switch matrix imposes various voltage levels and phasing on the primary winding so as to produce a regulated system output voltage.

Abstract: A polyphase line voltage regulator which uses polyphase pulse saturable ferroresonant reactors in series with three separate and equal input chokes. The line voltage regulator is particularly suitable for computer operations which impose a variable current demand on the power source. The input chokes are directly coupled with an unregulated a.c. source and are provided with controlled non-linearity. LC tuned circuits inhibit the second and third harmonics from the regulated a.c. voltage. An isolation transformer is connected across the polyphase pulse saturable ferroresonant reactors and delivers a voltage regulated a.c. output voltage to a load.

Abstract: A variable frequency drive for a motor-generator/alternator set which is used to supply electrical power to computer or data processing equipment. Power failures in commercially supplied power results in aberrations and erroneous computations in computers and data processing equipment. An induction motor is used to drive a generator/alternator. The induction motor is driven below the synchronous speed of the generator/alternator and a variable speed drive increases the velocity supplied to the generator/alternator, preferably to a point above its synchronous speed. Therefore, when there is a commercial power failure, the generator/alternator remains within a desired frequency range for a longer period of time than a comparable generator/alternator driven at synchronous speed.