Abstract: The invention relates to a circuit assembly (10) for fault detection in an ungrounded high-voltage system (20) having a connected inverter (4) and having at least one resistor (5) between a high-voltage potential (7a, 7b) of the high-voltage system (20) and a reference potential (8), the circuit assembly (10) comprising: a sensing circuit (1), which is designed to tap a voltage from the resistor (5), to generate a first measurement value therefrom and to provide the first measurement value at an output (1c, 1d); and an evaluation device (2), which is connected to the output (1c, 1d) of the sensing circuit (1), the evaluation device (2) being designed to compare the first measurement value with a first limit value and to output a first signal if the first measurement value exceeds the first limit value.

Abstract: A method for estimating a property of an electrical switching device includes: detecting a movement of electrical contacts of the switching device beyond an opening threshold; measuring, for at least one phase of the electrical device, the electric current through this phase; evaluating, for at least one phase of the electrical device, the voltage of an electric arc between the electrical contacts that are associated with this phase; and calculating, for at least the phase of the electrical device, an energy value associated with the electric arc, by numerically integrating the product of the measured electric current and of the evaluated voltage, the integration being performed over a time interval starting from the detection of the movement of the electrical contacts.

Abstract: An electrical full bridge strain gauge circuit, load cell, and load detection device for use in lifting platforms such as forklifts, loaders, cranes, and trucks, wherein the detection of the weight of a given load is desirable. The circuit includes a full bridge strain gauge configuration having a pair of voltage supply terminals and a pair of signal terminals, first resistors connected in series between the supply terminals and having a first tap between two resistors, and second resistors connected in series between the signal terminals and having a second tap between two resistors. A comparer has input terminals connected to the first and the second taps, for comparing a first voltage potential at the first tap with a second voltage potential at the second tap, and for producing a corresponding drift signal.

Abstract: An apparatus and method for the measurement of a resistance of a switching contact of an electrical circuit breaker. A first resistance value across the circuit breaker is determined while the circuit breaker is grounded at both sides and the switching contact is closed. Further, a second resistance value across the circuit breaker is determined while the circuit breaker is grounded at both sides and the switching contact is open. The resistance of the closed switching contact is then determined based on the first resistance value and the second resistance value.

Abstract: An operation circuit is set to a conductive state in a case where a three-phase alternating-current power supply switching circuit receives an R phase and an N phase. An internal switch is set to a non-conductive state in a case where the state of the operation circuit is the conductive state. One contactor electrically connects an input terminal to output terminals in a case where the state of the operation circuit is the conductive state. Another contactor electrically disconnects input terminals from the output terminals in a case where the state of the internal switch is the non-conductive state.

Abstract: A malfunction determining unit 7 compares an absolute value of the difference between a first count and a second count stored in a storage unit 8 with a predetermined threshold. If the absolute value is less than a predetermined upper limit, the malfunction determining unit determines that a contact unit 1 has no malfunction. If the absolute value is the upper limit or more, the malfunction determining unit 7 determines that the contact unit 1 has malfunction, and supplies the determination result to a control unit 3. The control unit 3 allows an output unit 10 to output a malfunction detecting signal if receiving the determination result indicating the presence of malfunction from the malfunction determining unit 7.

Abstract: A circuit that detects if contacts in an HV contactor have been welded or stuck closed. The circuit includes a controller that generates a short duration pulse signal that closes a driver switch and allows current flow through a coil in the HV contactor. The current flow is converted to a voltage by a sensor, where the voltage is received by the controller. The controller uses the voltage, such as by comparing the voltage to a stored representative voltage of the coil current for when the HV contactor is open, to determine whether the HV contactor is closed, and possibly welded or stuck closed, or partially closed. The sensor can be the driver switch or another device, such as a resistor.

Abstract: There are provided an evaluation device and an evaluation method for a substrate mounting apparatus capable of simply evaluating a temperature control function of the substrate mounting apparatus depending on evaluation conditions or circumstances and an evaluation substrate used for the same. The substrate mounting apparatus holds a target substrate mounted on a mounting surface and controls a temperature of the target substrate. The evaluation device includes an evacuable airtight chamber in which the substrate mounting apparatus is provided; an evaluation substrate which is mounted on the mounting surface instead of the target substrate and includes a self-heating resistance heater; and a temperature measurement unit which measures a temperature of the evaluation substrate.

Abstract: A test circuit that senses a misaligned probe during a test includes a first power control section that senses voltage levels of a plurality of sensing lines and controls power supplied to a lower circuit section provided below a part of a pad group, and a second power control section that selectively provides an internal voltage in response to a sensing result of the first power control section.

Abstract: An apparatus and method for the measurement of a resistance of a switching contact of an electrical circuit breaker. A first resistance value across the circuit breaker is determined while the circuit breaker is grounded at both sides and the switching contact is closed. Further, a second resistance value across the circuit breaker is determined while the circuit breaker is grounded at both sides and the switching contact is open. The resistance of the closed switching contact is then determined based on the first resistance value and the second resistance value.

Abstract: A device for measuring the wear of the contacts of a switchgear device is described. The switchgear device is of the open circuit breaker type with offset pole-shaft, and the movable contact is mounted on a sliding support. Measurement of the wear of the contacts is based on evaluation of the over-travel of the movable contact in the closed position when the latter slides in its support. This over-travel is determined by measuring the residual rotation of the pole-shaft, preferably by a contact-less magnetic rotation sensor.

Abstract: A control module with interrupt function for an electric circuit breaker has a voltage input for a control voltage, an output carrying the control voltage to which output an interrupter for the circuit breaker can be connected, an input for the control voltage fed back from the interrupter, a terminal for the circuit breaker, said terminal being connected to the input, and a measuring unit for measuring current and/or voltage at the input and at the output. An electric protection system has an electric circuit breaker, an interrupter and a control module.

Abstract: A method and system to monitor a high voltage power relay operable to conduct electrical power from a source to a load, during each vehicle shutdown event. The system includes the electrical relay with a resistive device, electrically connected in parallel circuit, a controllable electrical load device, and a sensing device. A controller is connected to the electrical relay and each sensing device, and operable to identify a low electrical load condition at the load. The controller commands the load to operate at a known current draw level, commands the relay open, and monitors a change in power to the load device when the relay is commanded open. The electrical relay is functioning properly when the change in electrical power to the load exhibits a known profile over time, when the electrical relay is controlled to the commanded-open position.

Abstract: A circuit for preventing corrosion of a contact, includes an input terminal, a signal line, a switch, an impedance element, and a comparator. The input terminal is to be connected to the contact, which is outside the circuit. The signal line is connected to the input terminal. The switch is connected to the signal line. The impedance element is connected to the signal line in parallel to the switch. An impedance of the switching section is smaller than that of the impedance element. The comparator compares a potential of the signal line with a predetermined potential. The switch is turned on based on a comparison result output from the comparator.

Abstract: An apparatus for preventing corrosion of a contact includes a detection conducting path connected to the contact, a variable impedance unit and a comparing and switching unit. The variable impedance unit is connected to the detection conducting path. The variable impedance unit is switchable between (i) a first impedance used for passing a corrosion prevention current into the detection conducting path and (ii) a second impedance through used for passing a current, which is used for detecting a connection state of the contact, into the detection conducting path. The first impedance is lower than the second impedance. The comparing and switching unit compares a detected value with a corrosion threshold, compares the detected value with a restoration threshold and switches the variable impedance unit based on comparing results.

Abstract: A method and an apparatus are disclosed for measuring contact erosion in an electrical switching device by a dynamic resistance measurement (DRM). To determine an overlap time and a contact erosion in an exemplary switching device, a change in current across the switching device can be measured indirectly by a measurement current being passed across the switching device and a parallel conductor, the change in current in the parallel conductor being measured. Exemplary embodiments relate, to the following: detection of a differential current measurement signal in the parallel conductor with the aid of a Rogowski coil; and selection of a parallel conductor resistance on an order of the switch resistance.

Abstract: The present invention is directed to a contact resistance test structure and methods of using same. In one illustrative embodiment, the method includes forming a test structure comprised of two gate electrode structures, forming a plurality of conductive contacts to a doped region between the two gate electrode structures, forcing a current through the test structure and determining a resistance of at least one of the conductive contacts based upon, in part, the forced current.

Abstract: A glide head assembly that can be used to certify disks of hard disk drives. The assembly includes a glide head that is coupled to a suspension arm. The assembly further has a contact sensor coupled to the head. The contact sensor includes a center plate and four beams. The beams are coupled to corresponding sensor elements. Contact between the head and the disk will cause the beams to deflect. The deflection of the beams is sensed by the sensor elements and processed to detect head/disk contact. The number, orientation and amplitude of the beams that are deflected can be processed to determine the pitch and roll angles of the glide head.

Abstract: A relay controller for connecting a power source includes at least one relay having at least two contacts. The relay controller includes a processing device operable to selectively switch the relay contacts, and a feedback circuit adapted to identify an actual state of the relay contacts. The processing device is configured to recognize a fault contact condition of a disparity between an expected state of the relay contacts and the actual state of the relay contacts. The processing device is also configured to responsively communicate information relating to the relay fault condition.

Abstract: A combined toroid/shunt device for detecting residual current in an electrical installation comprising a plurality of conductors such as a live conductor (2) and a neutral conductor (3) is described. The device comprises a toroid means (1, 4) for detecting an AC residual current within a first range and a plurality of resistive shunts (6a) to (6d) for connection in respective ones of the plurality of conductors. A current detection means (5, 7, 13) responsive to current flowing in each of said shunts for detecting a DC residual current and/or an AC residual current within a second range is described. The first range of AC residual current is an AC residual current resulting from earth leakage or cross-leakage between conductors up to a saturation level at which the toroid or electronic means associated means therewith becomes saturated. The second range includes an AC residual current of said saturation level.

Abstract: A method for monitoring a power output stage including at least one half bridge with upper and lower semiconductor switches connected in series, wherein the semiconductor switches are controllable alternately to a switched-on state and a switched-off state by pulse-width modulated pulses, includes measuring a first voltage across the lower semiconductor switch when the upper semiconductor switch is switched on and measuring a second voltage across the lower semiconductor switch when the lower semiconductor switch is switched on, comparing a difference between the operating voltage and the first voltage to a predetermined voltage and comparing the second voltage with the predetermined voltage, which is the maximum permissible voltage across a semiconductor switch when it is switched on, and determining that the power output stage or the output of the at least one half bridge is faulty when at least one of the difference and the second voltage is greater than the predetermined voltage.

Abstract: A contact impedance test circuit for testing impedance between a first contact element and a second contact element comprising an AC signal source for applying an AC signal voltage to the first contact element, an AC contact voltage being emitted by the second contact element, an AC amplifier connected to the second contact element for amplifying the AC contact voltage from the second contact element, an amplified AC contact voltage being produced by the AC amplifier, and a phase angle voltmeter for detecting phase difference between the amplified AC contact voltage and the AC signal voltage at an instance of time, the AC. signal voltage being applied to a reference input of the phase angle voltmeter, the amplified AC contact voltage being applied to a signal input of the phase angle voltmeter.

Abstract: A method and an electronic circuit for regenerating an electrical contact are provided in order to remedy the problem of electrical contacts becoming highly resistive over time. Electrical contacts become highly resistive over time, particularly when the contacts are thermally highly stressed and/or exposed to corrosive gases. To remedy this undesired effect and to reestablish the low resistance of the contacts, an electrical regenerating signal is applied to these contacts.

Abstract: In a switching device, a method and device for determining the wear of the pole contacts (C1, C2, C3) actuated by an electromagnet (20) whose movement is controlled by an excitation coil (21) by the variation of a contact wear distance travel time (Tu) generated during an electromagnet closing movement, by measuring at least one electrical signal (Ip) representing the conducting state of at least one power pole, by measuring an excitation current (Is) passing through the coil (21) of the electromagnet and by comparing the electrical signal (Ip) and the excitation current (Is) as a function of time. The measured wear distance travel time (Tu) can then be compared with an initial travel time (Ti) stored in the switching device.

Abstract: The invention relates to an apparatus and method to determine contact dynamics between conductive surfaces, and more particularly to determine the dynamics of contact closure in mechanical switches and analysis of the dynamics of other mechanical systems, in general. A log amp is in electrical communication with the RF synthesizer via a transmission line. The log amp outputs a voltage converted from an envelope of an RF waveform to determine a capacitance between at least two conductive surfaces.

Abstract: Methods, computer program segment and apparatus for analyzing high voltage circuit breakers are provided. The method includes determining a circuit breaker contact closing time, determining a circuit breaker contact opening time, and determining a circuit breaker pre-insertion resistor resistance value using at least three voltage samples and three current samples to facilitate reducing an induced current measurement error. The computer program segment is embodied on a computer readable media and is programmed to determine a circuit breaker contact closing time, determine a circuit breaker contact opening time, and determine a circuit breaker pre-insertion resistor resistance value using at least three voltage samples and three current samples that facilitate minimizing an induced current measurement error.

Abstract: An apparatus and a method for detecting high impedance failures in system interconnects. The apparatus and method may measure resistance of a connection of one or more representative sets of pins on a partitioned chip to a circuit board and determine if the measured resistance of each of the one or more representative sets of pins is less than a threshold value. The measuring step is executed while the circuit board is operating.

Abstract: Methods, computer program segment and apparatus for analyzing high voltage circuit breakers are provided. The method includes determining a circuit breaker contact closing time, determining a circuit breaker contact opening time, and determining a circuit breaker pre-insertion resistor resistance value using at least three voltage samples and three current samples to facilitate reducing an induced current measurement error. The computer program segment is embodied on a computer readable media and is programmed to determine a circuit breaker contact closing time, determine a circuit breaker contact opening time, and determine a circuit breaker pre-insertion resistor resistance value using at least three voltage samples and three current samples that facilitate minimizing an induced current measurement error.

Abstract: A component actuation circuit for an engineered safety features actuation system (ESFAS) includes a plurality of coincidence logic contacts, and a plurality of parallel-connected ESFAS component relays. Each of the coincidence logic contacts closes in response to a command signal. The plurality of parallel-connected ESFAS component relays are connected in series between at least two of the plurality of coincidence logic contacts. Closure of at least two of the coincidence logic contacts energizes the parallel-connected ESFAS component relays, thereby energizing a plurality of ESFAS components.

Abstract: A residual current detection device comprising a plurality of resistive shunts for connection in respective ones of a plurality of lines though which current can flow to and from a load, and detector means sensitive to the voltage developed across each of the shunts to detect any imbalance between the currents flowing though the shunts.

Abstract: A method and apparatus for testing a battery connection is provided. The apparatus includes a clamp attached to a conductor for attaching the conductor to an object, a first sensor configured to detect a voltage associated with the clamp, and a second sensor configured to detect a voltage associated with the conductor at a point located distally from the clamp, the voltage detected by the first sensor and the voltage detected by the second sensor are compared. A method for testing a connection includes sensing a first voltage in a cable carrying current to at least one of two and from a connection, sensing a second voltage associated with the connection, comparing the first and second voltages, determining whether the connection is acceptable or not acceptable based on the compared voltages.

Abstract: A method of monitoring contact burnoff in tap changers operating under load in which the load current is measured and for nominal variation of the voltage of the particular tap parameters are stored which are used to calculate the burnoff rate per contact per switching operation. From these values the cumulative burnoff rate of both the switching contact and resistance contact are determined and compared with limits or threshold values.

Abstract: In a method for testing the ground contact of parts of a networked system in which data are sent and received via at least one line, at least one line at each part is connected via a resistance arrangement to a common potential of the parts and is connectable via a controllable switch to a further potential. The voltage across the resistance arrangement is compared with a predetermined potential when the line is at one potential in a steady state, and the state of the ground contact of the part is deduced from a comparison of the voltage across the resistance arrangement with the predetermined potential.

Abstract: A method for determining switchgear-specific data at contacts in switchgear and/or operation-specific data in a network connected to the switchgear includes detecting a so-called contact follow-through travel at a switching path as an equivalent criterion for an erosion of contacts, particularly for contactor contacts. A resilience change during a shutdown cycle is measured, can be used to determine the erosion and can be converted into a remaining contact life for the contacts. Accurate measurement of the armature movement from a start of the armature movement to a start of contact opening is required for that purpose. Switching states of a switching device and of the electrical network are additionally detected from signals for resilience detection. An apparatus for carrying out the method is also provided.

Abstract: A method and apparatus for measuring the contact resistance at electrode-to-workpiece and workpiece-to-workpiece interfaces for spot welding simulations. A constant compressive load is applied through electrodes and workpieces to simulate a load applied during an actual resistance spot welding process. A discharging current circuit applies an initial high current of the order of 1.2 KA to electrodes and workpieces to break down contaminant films on surfaces of the workpieces. A relatively small constant current of about 2A is then applied to the electrodes and workpieces and the voltage across and the current flow through the electrodes and workpieces are measured. The contact resistance is determined from the measured voltage and current.

Abstract: A method and apparatus for determining contact resistance (107) includes pressing a lead connector (105) to make a first contact with a metallic pad (103) and an isolated contact with an isolated metallic pad (108) located adjacent to metallic pad (103). Once the first and isolated contacts are formed, the method includes flowing electrical current at a predetermined level through the isolated contact. With the aid of a volt meter (110), voltage differential across the isolated contact is measured while the electrical current at the predetermined level is flowing through the isolated contact. The contact resistance (107) of the first contact is determined based on information obtained from the voltage differential measured across the isolated contact and the predetermined level of the electrical current. Furthermore, the contact force created at the first contact is determined based on the contact resistance (107).

Abstract: A contact resistance check circuit and method for verifying that a sufficient electrical connection is established between a source and a sense lead of a Kelvin connection. The circuit includes a microprocessor for driving a transformer that is connected to the source/sense probe (i.e., contact resistance) with an input pulse. The input pulse is altered in relation to the magnitude of the contact resistance to produce a check pulse. A comparator is used to compare the check pulse with a threshold voltage and for generating a fault indication signal. A flip flop then stores the fault indication signal so that the fault indication signal may be monitored by the microprocessor.

Abstract: A contact resistance check circuit and method for verifying that a sufficient electrical connection is established between a source and a sense lead of a Kelvin connection. The circuit includes a microprocessor for driving a transformer that is connected to the source/sense probe (i.e., contact resistance) with an input pulse. The input pulse is altered in relation to the magnitude of the contact resistance to produce a check pulse. A comparator is used to compare the check pulse with a threshold voltage and for generating a fault indication signal. A flip flop then stores the fault indication signal so that the fault indication signal may be monitored by the microprocessor.

Abstract: A switching device including a measuring means for monitoring contact erosion, which is provided between a contact element and an associated contact support. The switching device includes an electrically insulated signal line, which is usable in individual and/or multiple contacts, is used as the measuring means, the signal line being integrated into a single monitoring circuit. In the switching device, there is arranged, between at least one of the contact elements and the associated contact support or in the contact material, an electrical conductor with insulator as the signal line, damage to or destruction of the insulator and/or the conductor being utilized to generate an external signal as an indication of the end of the service life of the contact element.

Abstract: A unit for testing infrared radiation detection units which incorporate relay contacts that are readily rendered defective by increasing resistance through use, thereby rendering the infrared radiation detection unit defective or inaccurate. As an example, such radiation detection units which are tested include hot metal detectors, loop controllers or scanners, and optical barrier units used in steel manufacturing. The testing unit includes an infrared radiation source for radiating infrared rays to an infrared radiation detector on a detection unit to be tested, and the testing unit further includes a relay contact resistance tester for measuring resistance of the relay contacts which is comprised of a plurality of light emitting diode indicators connected in parallel with each other through a resistor current divider network which is connected in series with a power source and the relay contact in the unit to be tested.

Abstract: A resistance checker portion for terminal posts of an energy storage device includes a series branch formed of an ohmic resistor at a switch connected in parallel to the energy storage device through the terminal posts. Brief closing of the noramlly open switch causes a voltage jump in the series branch which is a direct measurement of the resistance of the terminal posts. An evaluator measures the voltage jump and calculates the contact resistance of the terminal posts therefrom.

Abstract: Switches of telephone grids are tested for delayed action subsequent to, but within a number of milliseconds after, actuating the opening or closing of the switches. Excessive delay indicates approaching failure.

Abstract: An assembly is provided for testing one or more contact material samples in a vacuum environment. The samples are positioned as an inner conductive cylinder assembly which is mounted for reciprocal vertical motion as well as deflection from a vertical axis. An outer conductive cylinder is coaxially positioned around the inner cylinder and test specimen to provide a vacuum enclosure therefor. A power source needed to drive test currents through the test specimens is connected to the bottom of each conductive cylinder, through two specially formed conductive plates. The plates are similar in form, having a plurality of equal resistance current paths connecting the power source to a central connecting ring. The connecting rings are secured to the bottom of the inner conductive assembly and the outer cylinder, respectively. A hydraulic actuator is also connected to the bottom of the inner conductor assembly to adjust the pressure applied to the test specimens during testing.

Abstract: In the testing of dry circuit contacts, a constant current source is applied to the contacts. The open circuit voltage of the source is set to a predetermined maximum value and then the short circuit current at the contacts measured. If the current value is below a predetermined maximum value, the voltage of the source is increased to bring the short-circuit current to the predetermined value. The voltage drop across the contacts is then measured and the contact resistance calculated. This arrangement makes adjustments to take into account variations in the test circuit, such as different lead lengths and other variables, without subjecting the contacts at any time to an open circuit voltage or short circuit current above maximum values.

Abstract: A method and device is disclosed for the measurement of contact resistances of galvanic surfaces. Such contact resistances are subject to very great fluctuations. In order to measure the contact resistance, several wire pieces are provided with the galvanic surface. These wire pieces are stacked crosswise over one another and are pressed against one another with a defined pressure. The total resistance is measured between the uppermost and lowermost wire piece, and this total resistance is then divided by the number of points of contact.

Abstract: Probe apparatus having a pair of folded electrodes is arranged for use in detecting and measuring contamination films and foreign material appearing on connector contact terminals. The probe apparatus (1) comprises an insulation support member (2) positioned between two dielectric elements (31, 41) each having a surface plated with electrically conducting elements (32, 42) joined at one end of the insulation member to form a folded electrode (33, 43) and left free at the other end to form two lead-in terminals (34, 35, 44, 45). The combined insulator support member and dielectric contact elements are mounted in a test head assembly so that operation of the test head assembly inserts the probe apparatus into a connector contact terminal to engage the two folded electrodes with the connector contact terminal.

Abstract: Circuit board analysis system, featuring, in various aspects, a probe having three equally spaced tips to simultaneously contact a straight portion of a mounted IC lead, circuitry to monitor contact between the tips and the lead, use of very low level test signals while the board is powered up, and test signal injection to determine the absolute values of internal IC resistance.

Abstract: A technique and a circuit is described for readily detecting contact resistance build-up and contact chatter. Closed contacts are arranged in series with each other and with a resistor. A voltage is applied across the series arrangement. Each contact is shorted by jumper lead and/or separately jolted. If the contact is defective, the voltage step or series of voltage pulses will appear at the junction between the resistor and the contacts in series. The voltage step or pulses are coupled through a capacitor to a normally on switch which changes state to indicate the presence of the pulse indicating the defective contact. A resistor coupled to the capacitor provides a differentiating circuit to bleed off any charge in the capacitor to permit sequentially testing each contact. A further resistor in combination with the capacitor provides an integrating circuit to assure appropriate capacitor charging in response to the negative going pulses that occur when there is contact chatter.