Abstract: A circuit is provided for rectifying and amplifying an AC input waveform to optimize the dynamic range of downstream circuitry, such as an analog-to-digital converter. The circuitry includes an inverting amplifier and a non-inverting amplifier. The inverting amplifier includes a selectable resistance network in a feedback loop that permits the gain to be adjusted by appropriate selection of conductive states of solid state switches. The non-inverting amplifier includes a selectable resistance network on an input line. A control circuit, such as a microprocessor, monitors the output of the A/D converter and controls the conductive state of switches in the feedback and input networks to maintain the digital output within a desired portion of the dynamic range of the A/D converter. Several discrete gains may be provided and programmed in accordance with a predetermined selection scheme.

Abstract: The invention includes a transformer for converting three-phase AC power to nine-phase AC power. An autotransformer includes three coils, each coil including a plurality of serial windings that together form a polygon. Nine output nodes are provided between adjacent winding pairs, the windings sized and arranged such that adjacent output voltages are separated by 40 degree phase shift and such that output voltage magnitudes are essentially identical. Both step-up and unity gain input node sets are provided wherein, when three phase AC supply lines are linked to the step-up input set the output voltage is stepped up and when the three phase AC supply lines are linked to the unity gain input set the transformer gain is unity. An isolation transformer includes a secondary arranged like the autotransformer configuration described above.

Abstract: A tool for programming non-volatile memory is embedded in the form of an object in a programmable controller module, and can be used to transfer a firmware program to a plurality of different modules connected by a common network. The tool can be placed in any type of module, and can be used to transfer a firmware program to any type of module, regardless whether the two module types are the same or different types. The firmware program is received in a first module from a user interface by way of a communication link, which may be relatively slow. The object is embedded in the first module and has a plurality of services and attributes which are adapted for transferring the firmware program to a plurality of target modules. The first module and the plurality of target modules are connected by way of the common network, which is preferably a high speed network.

Abstract: A local clock used for synchronizing events in an industrial control system may be synchronized with a master clock according to synchronization signals received at a first period. Updating of the local clock is performed on a more frequent basis than the receipt of the update signals. By using the update signals to derive an error value which is incrementally applied to the clock at a much higher rate, the maximum deviation is reduced. The system works with clocks having discrete frequency outputs by adjusting the update rate so as to effectively produce a continuously variable output frequency for the local clock over an interval equal to the update rate.

Abstract: A cable and modular connector system are provided for a power and data transmission network. The cable includes a pair of power conductors and a pair of signal conductors disposed in an insulative cover. The conductors are positioned to minimize differential mode noise imposed on the signal conductors by external sources. The connectors include a base module which is coupled conductors in the cable by insulation displacement members. Once installed, the base module may remain resident on the cable. An interface module is fitted to the base module for connecting a node device to the cable conductors via the modular connector. The system facilitates installation while providing a high degree of immunity to noise.

Abstract: An electromagnetic operator includes first and second coils wound coaxially An armature partially surrounds the coils for channeling flux during energization of the coils. The armature may be formed of a bent plate and secured to a ferromagnetic support. A control circuit applies energizing signals to the coils during operation. Both coils are energized during an initial phase of operation. One of the coils is subsequently released or de-energized automatically. A timing circuit removes current from the second coil after a variable time period. The time period may be a function of the configuration of the timing circuit, such as an RC time constant, and of the energizing signal.

Abstract: A method and apparatus for maintaining both a DC bus voltage and a motor current within limit values wherein, when a voltage limit condition occurs, a voltage error (i.e. DC bus voltage limit minus DC bus voltage) is used to increase an inverter output frequency until the voltage limit condition subsides, and, wherein during a current limit condition a current error signal (i.e. motor current limit minus motor current) is used to reduce inverter output frequency until the current limit condition subsides, a slew rate used to control the output frequency when neither a current nor a voltage limit condition exists, the slew rate decreased as a function of the voltage limit period durations and increases a function of the current limit period durations.

Abstract: An operator assembly for an electromagnetic switching device includes a pair of insulative boards arranged in mutually facing relation. A first board carries first contacts, which may be arranged in pairs, while a second board carries second contacts designed to engage the first contacts upon closure. The first and second boards are pivotally secured to one another to rock between open and closed positions. A biasing member urges the board towards a normal position. The first board supports an electromagnet assembly and conductive traces for transmitting energizing current to the electromagnet coil. The second board supports an armature which is displaced under the influence of the electromagnet assembly during energization, thereby pivoting the boards with respect to one another against the force of the biasing member, and moving the first and second contacts into engagement.

Abstract: A method and apparatus for measuring the amount of free water contained within a substance includes a waveguide having front and back sides disposed opposite each other. The waveguide defines a chamber for propagating a microwave signal therethrough. The waveguide has an end perpendicular to the front and back sides which forms a short within the chamber. The front and back sides each have an aperture for passing a substance therethrough. A microwave signal in the frequency range of 10-25 gigahertz is directed through the chamber wherein the generated microwave signal is reflected back from the short of the end. The generated and reflected signals form a ratio which is used by a microprocessor along with the measurement from an adjacent sensor that provides a dielectric constant measurement corresponding to the density of the substance in order to determine a weight of the substance compensated for free water.

Abstract: A programmable analog I/O circuit for use in an industrial control system has a first mode of operation as an input circuit and a second mode of operation as an output circuit. In the first mode of operation, a device-side I/O terminal is adapted for receiving an analog input status signal from an analog input device. In the second mode of operation, the device-side I/O terminal is adapted for transmitting an analog output control signal to an analog output device. According to another aspect, a programmable I/O circuit that drives an output device in an industrial control system comprises a plurality of configurable gain stages and a plurality of programmable isolating links. The plurality of programmable isolating links are coupled to the plurality of configurable gain stages and are programmable to determine a series or parallel arrangement of the plurality of configurable gain stages.

Abstract: A cross current compensation system for controlling reactive currents in a generator is provided. A control system for receives voltage feedback from a first generator of a plurality of generators and cross current feedback from at least a second generator of the plurality of generators. The control system determines a phase angle based on the voltage feedback from the first generator and cross current feedback from the at least a second generator. The control system determines a compensation signal corresponding to the phase angle and cross current feedback. The control system modifying a generator excitation signal for the first generator based on the respective compensation signal and a bi-linear transformation technique.

Abstract: A modular emergency stop device including a switch unit and a control unit. The switch unit includes a switch which converts from a normal state to an emergency state when an emergency stop is necessary and a housing for the switch. The control unit includes a controller which controls a power source for a machine and a housing for the controller. The switch unit's housing and the control unit's housing are adapted to be selectively coupled together and uncoupled from each other. The switch is operably coupled to the controller when the housings are coupled together whereby the controller may appropriately control the machine's power source when the switch is converted to the emergency state. To replace the switch, the switch's housing is uncoupled from the controller's housing to remove the switch unit and a new switch unit is coupled to the controller's housing.

Abstract: Electrochemical surface analysis using a deoxygenated gel electrolyte provides advantages over a liquid electrolyte in processes such as sequential electrochemical reduction analysis. In sequential electrochemical reduction analysis, a solderable portion of an electronic component or circuit board to be tested is placed in contact with a deoxygenated gel electrolyte such as a borate buffer solution having a gelling agent. The gel electrolyte prevents capillary attraction up or along a lead of the component so that the power source cathode lead does not contact the electrolyte and electrochemical analysis can be localized to the area of interest, such as the portion of the component lead to be soldered. Interfering effects of atmospheric oxygen are minimized for deaerated gel electrolytes because convection mixing is practically absent and diffusion is generally a very slow process in a gel.

Abstract: An apparatus to be used with a PWM VSI which is linked by voltage supply cables to either a passive or a dynamic load, the VSI providing voltages on the cables which have at least one primary harmonic component, the apparatus linked to the output terminals of the VSI and including a line inductor between each output terminal and the load and, for each cable, at least one resonant filter branch including an inductor and a capacitor linked to each of the supply lines and to a common node wherein the line inductors are chosen so as to limit filter current and the branch elements are chosen such that a resonant frequency thereof is essentially equal to the frequency of the primary harmonic component.

Abstract: A multiphase circuit interrupter includes a plurality of power phase sections for establishing and interrupting electrical power carrying paths for a plurality of phases Each power phase section includes first and second conductive regions which contact one another to complete the current carrying path for the phase. The second conductive region is movable to an interrupted position to interrupt the path. An interphase current carrying path is established between the power phase sections to conduct electrical energy between the sections following a trip event in any one of the sections. The interphase current carrying path may be established by a conductive element extending between the power phase sections. Channels may be formed in the interrupter housing between the power phase sections to communicate conductive plasma generated during separation of the contact regions from one another between the power phase sections.

Abstract: A circuit for and method of controlling transient currents on power conductors includes a voltage-controlled switch connected between one of the power conductors and a load. A turn-on circuit is connected to the switch to control the switch during a transition period in which the switch changes from a non-current conducting state to a conducting state in which a static current flow to the load can be maintained. The turn-on circuit controls turn-on such that the rate of rise and the peak amplitude of the current through the switch is limited during the transition period. A reset circuit also is connected to the voltage-controlled switch to reset the switch to a non-conductive state when the voltage between the power conductors drops out. The reset circuit is configured to reset the switch within a reset period having a duration that is shorter than the duration of the transition period.

Abstract: A multilayer circuit board or laminated circuit board for use in a motor controller is described. The multilayer circuit board is preferably utilized as a power substrate module. The power substrate module includes a mounting area provided in a recess, window or portion of the circuit board where the circuit board is only a single layer thick. The insulated mounting area is provided in a blind via in the multilayer circuit board. The single circuit board layer at the mounting area provides a heat conductive yet highly electrically insulated mounting area for receiving a heat sink. The heat sink can be mounted on a side opposite the electrical device. The heat sink may be standard heat sink or a copper coil directly soldered to the circuit board. The multilayer circuit board includes an enhanced conductive layer for receiving the surface mount device. The enhanced conductive layer preferably includes an insulative frame which holds copper slugs.

Abstract: The invention includes an autotransformer for converting three-phase AC power to twelve-phase AC power using only three coils (e.g., no primary or dead windings are required). The autotransformer includes three coils, each coil including a plurality of serial windings that together form a polygon. Twelve output nodes are provided between adjacent winding pairs, the windings sized and arranged such that adjacent output voltages are separated by 30 degree phase shift and such that output voltage magnitudes are essentially identical. In some embodiments step-up, step-down and unity gain input node sets are provided while in other embodiments unity gain and either step-up or step-down input node sets are provided. The invention also includes an isolation transformer configuration that uses a secondary configuration that is identical to inventive autotransformer configurations.

Abstract: A switch assembly is provided that comprises a switch having a normally open contact and a normally closed contact which is electrically connected to the normally open contact and which is located either within the same housing as the normally open contact or a separate housing. The housing(s) may be mounted onto a latch assembly which, in turn, is mounted onto a switch operator, thereby closing the normally open contact. If the latch assembly becomes mechanically disengaged from the switch operator, thereby rendering the normally closed contact non-operational, the normally open contact will open, thereby opening the circuit to a machine performing a controlled function. The user, noticing the stoppage of operation, will then be alerted of a malfunction within the switch assembly.

Abstract: An electrical contactor includes an electromagnetic operator which may be powered by either AC or DC power. For use with AC power, a rectifier circuit converts AC waveforms to DC waveforms and applies the converted power to DC one or more DC coils. The rectifier circuitry applies DC power directly to a bus. A pair of coils may be used, such as separate pickup and holding coils. The pickup coil may be de-energized after an initial phase of operation. To permit rapid release of the holding coil, a control circuit interrupts an induced current path through the coil upon removal of power from the bus.