Abstract: A non-ferrous current sensor is used to continuously measure the charging current magnitude in step-graded foil and paper insulation systems and capacitive insulation systems used on high voltage measurement and control apparatus such as instrument transformers and on the condenser bushings of power transformers and circuit breakers. The low voltage measured signal is conditioned by an electronic circuit such that it modulates a DC signal in a system current control loop to provide continuous remote monitoring and alarm functions. Remote power is supplied to the sensor and conversion circuits through the current loop. The sensor detects changes in the charging current through the insulation ground conductor, indicating the degradation of the dielectric properties between the foil layers. The sensor and associated electronic circuitry are enclosed in a housing adaptable to be used with a capacitance tap common to high voltage measurement and control apparatus.

Abstract: A programmable data link module (32) for use in a time division multiplexing control system (30) having a plurality of modules interconnected by a bus (40) for passing control signals between data link modules on a serial multiplex basis. Each module includes an integrated circuit (80) having signal conditioning circuits (180, 186 and 188) including a programmable hysteresis circuit (126), a power on reset delay circuit (190), a safety input inhibit circuit (220), a clock loss detect circuit (240), a safety output protection circuit (262), a data verifier (260), a polarity selector for a third output terminal (350), an input synchronizer (182 and 184), a combined mode/sync output terminal (110), a multiplex clock output terminal (108), a programing circuit (232) for accepting programming over the clock bus (44) and data bus (46), input/output word extender circuits (104, 106), a high voltage protection circuit (420) including a transistor (600) and a data bus integrity checker (630).

Abstract: A system for modifying a printed circuit board allows parallel design of the printed circuit board and a programmable gate or logic array used on the circuit board. The printed circuit board design can be fixed before the gate array design is complete, which allows for flexibility in pin assignments of the high density integrated circuit mounted on the circuit board. Each pin of the gate array that can vary has a pair of vias connected by a conductive track. Changing signal paths requires cutting this track and using a jumper to make the new connection.

Abstract: A single phase, dry type transformer has an iron core, high voltage windings embedded in cast resin, and low voltage windings resin encapsulated. The low voltage winding is constructed with flexible sheet conductors. Insulating material includes a means to secure the windings in place during a vacuum and pressure resin impregnation process. The result is a coil that exhibits high short circuit protection due to the tightly bond conductors comparable to completely resin encased molded transformers at a substantially reduced cost.

Abstract: A coil assembly for use in an inductive apparatus, is comprised of a conductive material, either copper or aluminum, continuously wound around a circular or rectangular shape. At a predetermined number of turns, a terminal or tap is formed in the conductor. The tap is essentially a bump in the conductor that will protrude from the coil and be accessible to make connections to it after the coil assembly is complete. The insulation of the conductor is removed from the outside edge of the bump to form a point of contact. A C-clamp, formed from spring steel or other conductive material, functions to secure an external conductor having a lug attached to an end of conductor to the formed terminal. A bolt through the lug is secured by a tapered depression in the C-clamp that functions as a nut. The C-clamp includes an extension that provides additional pressure between the point of contact and the lug to make an electrical contact with a portion of the formed tap and the lug.

Abstract: A user interface for a control structure comprising a controller, and physical devices coupled to the controller is disclosed. The controller is adapted to control and monitor the physical devices. The user interface is coupled to the controller for displaying representations of status conditions of the physical device.

Abstract: A dry type transformer has an iron core, high voltage windings embedded in cast resin, and low voltage windings resin encapsulated. The low voltage winding is constructed with flexible sheet conductors coincident with layer insulation sheets that extend beyond the edge of the sheet conductor. Cooling air ducts are fabricated in the low voltage windings as it is wound. To prevent the extension of the layer insulation sheets from collapsing over the formed air ducts during a vacuum and pressure resin impregnation process, reinforcing means are added to the extensions to prevent them from collapsing.

Abstract: The present invention locates the primary winding of a transformer in a configuration where it substantially surrounds the secondary winding of the transformer in order to enhance the efficiency of the electromagnetic coupling. High magnetic permeability material surrounds portions of the primary winding of the transformer. The transformer is designed to efficiently operate at frequencies of approximately 50 kilohertz. In one preferred embodiment, the primary winding of the invention is formed of two U-shapes in which the parallel members of the U are substantially longer than the bottom portion of the U. The two U-shapes form a rectangular shape and the substantially parallel rectangular portions are surrounded by high magnetic permeability material to further enhance the electromagnetic coupling between the primary coil winding and the secondary coil winding. In another embodiment, the primary winding of the invention may be rectangular in shape.

Abstract: A baseball pitching apparatus having an unique light weight tubular steel frame separable into components parts and a fabric drape the makes it easy to transport, erect, use and disassemble. The frame and fabric drape combination hold the target area erect while effectively dissipating the energy and redirecting the baseball without any complicate mechanical or electrical mechanisms.

Abstract: A non-ferrous current sensor is used to continuously measure the charging current magnitude in step-graded foil and paper insulation systems and capacitive insulation systems used on high voltage measurement and control apparatus such as instrument transformers and on the condenser bushings of power transformers and circuit breakers. The low voltage measured signal is conditioned by an electronic circuit such that it modulates a DC signal in a system current control loop to provide continuous remote monitoring and alarm functions. Remote power is supplied to the sensor and conversion circuits through the current loop. The sensor detects changes in the charging current through the insulation ground conductor, indicating the degradation of the dielectric properties between the foil layers. The sensor and associated electronic circuitry are enclosed in a housing adaptable to be used with a capacitance tap common to high voltage measurement and control apparatus.

Abstract: A control system (FIGS. 2, 3, 5, 6) and method in which multiple levels, or stages (128, 130, 132), of logical decisions are made by selectively feedforwarding output signals (356) from control modules (72) to the inputs of other modules (80), preferably through use of control modules (233) with selective feedforwarding circuits (239, 240) to logically combine during selected synchronous time slots (351) of a synchronous clock signal (FIG. 11) the result of a plurality of nonconcurrent input signals from a plurality of input devices (28, 30, 32, 34) to control an output device (26).

Abstract: There is disclosed a two wire AC power supply for proximity switch integrated circuits. A problem has existed with previous power supplies in that such have been implemented using discrete devices, which take up valuable room on any printed wiring assembly. This invention therefore provides a two wire AC power supply for a proximity switch integrated circuit, wherein at least some circuitry associated with the power supply is provided within the integrated circuit. The power supply preferably comprises a bridge rectifier (BR1), a voltage regulator (Z1, R1, M1), a thyristor (SCR), a diode (D1), a storage capacitor (CVS), a comparator, and an AND gate, wherein at least the comparator and the AND gate are provided within the integrated circuit.

Abstract: A programmable data link module (32) for use in a time division multiplexing control system (30) having a plurality of modules interconnected by a bus (40) for passing control signals between data link modules on a serial multiplex basis. Each module includes an integrated circuit (80) having signal conditioning circuits (180, 186 and 188) including a programmable hysteresis circuit (126), a power on reset delay circuit (190), a safety input inhibit circuit (220), a clock loss detect circuit (240), a safety output protection circuit (262), a data verifier (260), a polarity selector for a third output terminal (350), an input synchronizer (182 and 184), a combined mode/sync output terminal (110), a multiplex clock output terminal (108), a programming circuit (232) for accepting programming over the clock bus (44) and data bus (46), input/output word extender circuits (104, 106), a high voltage protection circuit (420) including a transistor (600) and a data bus integrity checker (630).

Abstract: A ground fault detection circuit monitors an interlock control circuit for use with a machine or process control system. The interlock control system utilizes electromechanical relays with hard contacts. The interlock control system will disable operation of the machine or process if any ground fault condition exists in the interlock control circuit. A ground condition in the machine or process control circuits is permissible. The system uses a redundant circuit path to verify the integrity of the components in the interlock control system. The control system includes an ungrounded isolation transformer for supplying power to separate monitoring relays interposed between each leg of the transformer and ground. The contacts of these relays are series connected with emergency-stop (e-stop) switches to energize interposing control relays. The outputs of the interposing relays are used to energize the final control relay that controls the operation of the machine or process.

Abstract: The present invention locates the primary winding of a transformer in a configuration where it substantially surrounds the secondary winding of the transformer in order to enhance the efficiency of the electromagnetic coupling. High magnetic permeability material surrounds portions of the primary winding of the transformer. The transformer is designed to efficiently operate at frequencies of approximately 50 kilohertz. In one preferred embodiment, the primary winding of the invention is formed of two U-shapes in which the parallel members of the U are substantially longer than the bottom portion of the U. The two U-shapes form a rectangular shape and the substantially parallel rectangular portions are surrounded by high magnetic permeability material to further enhance the electromagnetic coupling between the primary coil winding and the secondary coil winding. In another embodiment, the primary winding of the invention may be rectangular in shape.

Abstract: A system contained on a single isolation panel determines the hazard current of a dual voltage, ungrounded, polyphase system. The system uses a single isolation transformer having dual secondary windings for generating the dual voltages. A first line isolation monitor or LIM, is microcontroller based and continuously measures the fault impedance of one of the output voltages of the polyphase, ungrounded or isolated system. A second LIM continuously measures the fault impedance of the other output voltage of the system. The fault impedance is determined by the LIM by injecting a continuous sine wave measurement current into a ground terminal to generate a measurement voltage across the fault impedance. Using the measurement voltage and current, the LIM calculates the fault impedance and, using this impedance, calculates the hazard current based on the maximum line to ground voltage of the ungrounded system.

Abstract: The present invention converts an alternating current input into a direct current output by switching a current load at high speeds to create a voltage envelope having a maximum allowed voltage and a minimum allowed voltage. Complementary switching elements are employed to take advantage of both the positive and negative portions of an AC cycle. Load switching is arranged so that the current vector which represents the load is nearly coincident with the voltage vector which represents the power source. The system can operate in an open loop mode at a constant frequency, in a closed loop mode, or in a hysteresis mode. During open loop operation, the voltage envelope is not rigidly defined as the switching frequency remains constant. During hysteresis mode control, the voltage envelope remains fixed and the current switching frequency varies.

Abstract: A non-ferrous current sensor is used to continuously measure the charging current magnitude in step-graded foil and paper insulation systems used on high voltage measurement and control apparatus such as instrument transformers and on the condenser bushings of power transformers and circuit breakers. The low voltage measured signal is conditioned by an electronic circuit such that it modulates a DC signal in a system current control loop to provide continuous remote monitoring and alarm functions. Remote power is supplied to the sensor and conversion circuits through the current loop. Alarm level thresholds and alarm time delay are embodied in a control device which may be located in a remote location, away from the high voltage equipment. Step-graded insulation systems form a capacitively divided circuit between the high potential and ground. As the dielectric between the foil layers breaks down, the total capacitance of the insulation system increases, producing an increase in the charging current.

Abstract: A microprocessor based uninterruptible power supply generates an AC electrical output power from an AC input source when the AC input source is within settable voltage limits and from an auxiliary source of DC power when the AC input source is outside said the voltage limits. The microprocessor provides monitoring of the AC input voltage to determine its amplitude and frequency, and uses this information to set the magnitude and frequency of the AC output voltage and to select the source of the AC output power. A power factor improvement circuit boosts the selected source to a high DC voltage which is inverted by a chopper circuit to produce a high frequency AC voltage is rectified and sent to a PWM inverter to produce the AC output power. An average current feedback loop provides the output voltage regulation and utilizes current limiting to provide output current limiting for protection against short circuits and overloads.