Abstract: A method of performing a dielectric voltage-withstand test on a wire harness having a plurality of conductors includes applying voltage simultaneously to a first subset of the conductors. The first subset includes at least two of the conductors. An electrical characteristic of each of the conductors excluded from the first subset of conductors is measured. The applying and measuring steps are repeated for at least one additional subset of the conductors. It is decided whether the wire harness passes the test based upon at least one of the measuring steps.

Abstract: For an electrical system a sensor and associated circuits are provided for on-line monitoring of the state of the high-voltage insulation in the electrical system. In this arrangement, both the power frequency signal and of the radio frequency signals associated with partial discharge activity may be monitored and transmitted from the sensor to remote monitoring instrumentation. The sensor is disposed in a stand-off insulator which also may act to support the high voltage conductor system.

Abstract: A symmetrical voltage divider whose tap is supplied with a reference voltage via a resistor is connected between the terminals of an inductive sensor. A diagnostic voltage is applied to the tap. Using evaluation devices, the diagnostic voltage is compared with two threshold values in a stationary state, and then sampled in the operational state, and a difference is calculated from the largest and smallest sampled, values and is compared with a third threshold value. Short circuits or line interruptions are detected from the comparison result and are displayed.

Abstract: Disclosed is an electronic circuit assembled onto a miniature printed circuit board and assembled into an AC plug body such that the AC mains connect to terminals on or connected to the printed circuit board. The circuit contains a filtered power supply, microcontroller, and external interface, such that the plug may be connected to a special interface connector in order for data to be exchanged with a PC or computer or other programmer/reader device. A current sensor is employed and a voltage sensor is also employed. From the combined readings from the voltage sensor and the current sensor, the embedded program running on the microcontroller can determine the power being consumed by the loading device.

Abstract: A sensor and associated circuits are provided for on-line monitoring of the state of the high-voltage insulation in electrical equipment with capacitance tap. In this arrangement, both the power frequency signal and the radio frequency signals associated with partial discharge activity are sensed. These signals are transmitted from the sensor to remote monitoring instrumentation via one connecting cable. The sensor contains a surge arrester in parallel with a capacitor shunt, a radio frequency current transformer and a connecting circuit. The polarity terminal of the primary winding of the radio frequency current transformer is connected to the tap output. The non-polarity terminal is connected to the common connection point of the surge arrester and the capacitor shunt while the second terminals of these components are connected to the local ground.

Abstract: A test device is described for testing an electromagnetic quantity, such as a voltage or a magnetic field. The test device includes a housing, a sensor arranged in the housing and sensing the electromagnetic quantity, a processing circuit for processing to signals received from the sensor, display elements for displaying the signals processed by the processing unit, a galvanic element for supplying power to the test device, an illuminator for illuminating an area to be tested, and a switch for activating the illuminator. The test device has a small footprint and does not require an external light source even under difficult lighting conditions.

Abstract: A system for testing an arcing fault detection system in an electrical distribution network having a line conductor carrying an electrical signal between a power source and a load, the arcing fault detection system including a sensor coupled to the line conductor for monitoring the electrical signal and generating a sensor signal representing the electrical signal, the arcing fault detection system generating an arc-indicative signal in response to the sensor signal having characteristics indicative of an arcing fault. The testing system couples the sensor to a test line simultaneously with the line conductor and periodically produces a test signal on the test line. The sensor simultaneously monitors the test signal and the electrical signal and produces a sensor signal representing both the test signal and the electrical signal when the test signal is present on the test line.

Abstract: A method for identifying short circuits in a low-voltage network includes the step of determining a first envelope and a second envelope for a plurality of locus curves of a current steepness as a function of a current in a low voltage network, the first and second envelopes including all switching angles, the first envelope being determined for a lower power factor, the second envelope being determined for an upper power factor. Additionally a third envelope is determined taking into account rated-current switching operations between the lower power factor and the upper power factor. A resultant envelope is formed from a combination of the first, second, and third envelopes by overlaying the first, second, and third envelopes. The resultant envelope defines a tolerant locus curve criterion indicating a short circuit for values outside the tolerant locus curve criterion. A configuration for identifying short circuits is also provided.

Abstract: An electromagnetic waveform developing in synchronism with a system power supply by a partial discharge of electric equipment such as a power distribution device is received by an antenna 1. From the electromagnetic waveform of measurement frequency included in the received signal, there are extracted a component changing according to the frequency of the system power supply and a component changing at the frequency twice that of the system power supply. The presence or absence of discharge is determined from the magnitude of each of the extracted components, thereby detecting a partial discharge.

Abstract: A method and an apparatus for monitoring conditions of electric insulation in a live or energized electric system. The invention takes into account the fact that, when the insulation resistance of an electric system is measured under real live conditions, the electric insulation works under voltages and current-leakage conditions which different from those measured in so-called “cold” state. The invention is based on two voltage measurements in one of which the operating conditions of the electric insulation are artificially changed for a known value. Insulation parameters are then calculated by a set of formulas using the results of the two measurements.

Abstract: A resistance tester is incorporated into a grounding device. The resistance tester includes a test circuit, a battery, a switch and a set of indicator devices. With the grounding device being worn and the cord end of the device in contact with the user so as to form a closed circuit, the test circuit measures the resistance level of the grounding device upon activation of the switch. The indicator devices provide a visual indication of the resistance level, i.e., too high, too low or within acceptable limits. The resistance tester is self-contained and may be used anytime by the user to ensure that the resistance of the grounding device is acceptable.

Abstract: A ground detection apparatus for sensing the presence of a malfunction within an electronic instrument. The apparatus includes an active electrical circuit for delivering electrical energy from a power source to an electrically-driven instrument. The apparatus further includes a plurality of return electrical circuits connected in series with the active electrical circuit distal the electrically-driven instrument. A transformer coil is positioned within the apparatus such that the active electrical circuit includes a first winding about the transformer coil and such that one of the return electrical circuits includes a second winding about the transformer coil. The first and second windings are configured such that no substantial net flux is created in transformer coil when the plurality of return electrical circuits are functioning properly.

Abstract: An electrical testing device for determining the continuity between ground terminals of an electrical power cord and determining the electrical grounding of an electrical power tool. The electrical testing device can also be configured to determine the proper polarity on each of the hot, negative, and ground cord wires of an electrical power extension cord. The electrical testing device includes a plastic case housing one or more batteries which supply power to a test button and the ground terminal of a female receptacle installed in the case. The top surface of the case includes a female receptacle, a test button, and a ground light. The top surface may also include a male plug and an additional female receptacle installed in the case. On the side of the case is an extending metal contact element. The test button is a single pole momentary contact test button.

Abstract: The present invention provides automated systems for performing electrostatic discharge (ESD) device efficacy monitoring and recording the results for an ESD auditing program. Systems of the present invention comprise at least one ESD device monitoring unit. A communication system allows the monitoring unit to communicate with a central computer which collects, stores and allows the manipulation of the test data. Systems of the present invention are therefore useful in testing the ESD devices, documenting their performance, and controlling access to particular work areas based on testing results.

Abstract: A leakage tester includes multiple circuits capable of simulating the impedance of the human body to electrical current under a variety of conditions, and in which the multiple circuits can be selected using a single menu-based operator interface for testing both normal-line and single-fault conditions such as open-neutral, reversed-line, and open-ground conditions, as well as for performing additional types of safety compliance tests including dielectric withstand, insulation resistance, and ground bond or continuity tests, in any sequence.

Abstract: A method of determining the ground-fault current flowing in a multi-phase circuit is based on the use of standard current transformers having iron cores for the phase conductors and the neutral conductor. Allowance is made for the current-dependant linearity error of the current transformers by subtracting the product of the highest phase-current and associated error from the vectorial sum of the currents. This results in a single-sided position of the tolerance band of the measured ground-fault current and prevents spurious tripping.

Abstract: An electronic proximity switching device with a proximity indicator and with an electronic switch which can be controlled by the proximity indicator. A plurality of these switching devices can be series connected without an unacceptable voltage drop occurring on the series connection when the switching devices are conductive, by the electronic switch of each switching device being connected to one input (2) of an AND element (3), another input (4) of the AND element (3) representing a control input (5) of the switching device, the output (6) of the AND element (3) representing the output (7) of the switching device, and load current flowing via the AND element (3) in the conductive state of the switching device. In other words there is AND element (3) in addition to an inductive proximity switch (1).

Abstract: A device and method for monitoring the integrity of a ground connection between an electrostatic apparatus and earth ground. The device and method provide for continuous monitoring of the connection. The device includes an audible and visual alarm if there is a fault in the grounding connection. It also provides an audible and visual alarm if a DC power supply falls below a specified value. A switch is provided for testing the circuit manually to ensure its proper operation.

Abstract: A ground and bond detection device for ensuring that a conductive material, such at a metal container, is properly grounded to prevent electrostatic charge buildup. The device indicates whether a ground connection between the conductive material and ground exists, and whether the ground connection has been interrupted. The device is battery-powered, portable, and can be used on conductive material which is coated with nonconductive material such as paint, dirt, or rust. The ground and bond detection device provides low-cost, reliable, portable, and safe monitoring of ground connections for, e.g., metal containers used to store flammable materials.

Abstract: Improved electronic circuitry incorporated into a tag attached to a user worn wrist strap of a static electrical discharge dissipation system. The electronic circuitry monitors the electrical connection of the wrist strap from the user to ground and tests the functionality of the tag. The electronic circuitry comprises an oscillator, a signal transmitter, a discharge resistor and a discharge resistor check circuit for monitoring the accuracy of the discharge resistor. The electronic circuitry also comprises a skin resistance check circuit for monitoring the electrical connection of the wrist strap to the user, and a ground fault detect circuit for monitoring the electrical connection of the wrist strap to ground.

Abstract: An apparatus includes an insulated first switching element and a capacitor which are connected in series between one of positive and negative main circuit wirings connected to an ungrounded power source and a ground potential section (vehicle body); a second switching element with one terminal thereof connected to a junction point of the first switching element and the capacitor; switching element control device for selectively closing the first switching element for a predetermined time so as to charge the capacitor and for closing the second switching element so as to discharge the capacitor while the first switching element is opened; device for detecting the electric charge accumulated in the capacitor; and device for determining the insulation between the other of main circuit wirings and the ground potential section in accordance with the detected amount of charge.

Abstract: The noise received by the unused connectors limits the accuracy of a device for measuring the leakage from a piece of electronic medical equipment. To reduce noise the device is surrounded by a Faraday shield which encloses unused connectors of the device. The shielded connector includes a post having a transverse hole near its distal end. A coil spring surrounds the post end and is connected to the Faraday shield of the device. An insulated retainer prevents the distal end of the coil spring from extending beyond the end of the post. The retainer is compressed against the coil spring to expose the transverse hole when a lead is to be attached to the connector.

Abstract: A method for detecting ground faults between a community antenna television (CATV) coaxial cable and an appliance coupled to the CATV coaxial cable for receiving CATV broadcasts is provided. A potential difference between a shield of the coaxial cable and a chassis of the appliance is determined. A fault indicator is provided, if the potential difference exceeds a predetermined threshold voltage. An apparatus for detecting ground faults between an appliance and a CATV coaxial cable is also provided. The apparatus includes a comparator. A first input of the comparator is coupled to a chassis of the appliance. A second input of the comparator is coupled to a shield of the coaxial cable. The comparator indicates a fault condition if a potential difference between the first and second inputs exceeds a predetermined threshold.

Abstract: A system for the remote measurement of the protection ground associated with an electrical system, and which employs a telephone line for the transmission of the control signals and the results of the measurement. The system includes a centralized ground measuring device (1) having two reference grounds (11, 12) which are connected to the soil, a line selector (2) and remote actuators (3) which also include two ground terminals which are connected to the soil and which may be located near the region in which the measurement is required.

Abstract: An extension cord with integral monitoring system including a male connector having a pair of strip contacts. Such contacts include a neutral strip contact and a line strip contact. Further included is a female connector having a pair of receiving contacts residing within a pair of apertures formed therein. The contacts include a neutral receiving contact and a line receiving contact. Further included is a cable coupled between the male connector and the female connector. The cable has a neutral wire electrically connected between the neutral strip contact of the male connector and the neutral receiving contact of the female connector and a line wire electrically connected between the line strip contact of the male connector and the line receiving contact of the female connector. Next provided is a voltage monitor for indicating the presence of a voltage at the contacts of the female connector thereby signaling that the male connector is in proper electrical communication with the electrical receptacle.

Abstract: In an electric fence energizer there is an exterior earth connection such as an earth connection post (16). The electric fence energizer comprises in the conventional way a transformer (T) having a primary winding (L.sub.1) and a secondary winding (L.sub.2), one exterior terminal (9) of which is connected to the conductor (17) in the electric fence and the other exterior terminal (11) is connected to the earth connection, high voltage pulses being induced over the secondary winding (L.sub.2) when voltage pulses are applied over the primary winding (L.sub.1). For a determination of the quality of the earth connection, the voltage over a small part of the secondary winding (L.sub.2) is obtained capacitively by means of an extra winding (L.sub.3) in the transformer (T). For an evaluation of this voltage, it is connected, only for a determined polarity, to a charging circuit for a capacitor (C.sub.2), which is discharged over a known resistor (R.sub.2, R.sub.3). The voltage (V.sub.21) over this capacitor (C.sub.

Abstract: An apparatus detects a ground fault of an exciting circuit and a field circuit of an AC exciting variable speed rotating machine. The exciting circuit outputs an excited voltage controlled a frequency and/or an amplitude, and the field circuit of the AC exciting variable speed rotating machine is applied a field current by the excited voltage of the exciting circuit. A ground resistance is connected between a neutral point and a ground. The apparatus detects a current flowing from a ground to a neutral point through the ground resistance, and detects the ground fault based upon the detected current. Therefore, the apparatus can detect a ground fault of a field circuit and an exciting circuit of an AC exciting rotating machine during the AC exciting rotating machine operation with certainty.

Abstract: An equipment and method for detecting electrical leakage in an electric vehicle. For detecting occurrence of leakage in an alternating-current motor for driving the vehicle, a source-side transistor of an inverter is turned ON and a sink-side transistor is turned OFF. When leakage occurs in the motor, there arises an electrical path to an electric leakage detector through the grounded portion from the transistor on the source-side, the motor winding, and the leakage portion. Due to a current flowing in the electrical path, the electrical leakage detector determines that the leakage is present, and the result is notified to the ECU (electronic control unit). On the contrary, the source-side and sink-side may preferably be turned OFF and ON respectively. It is unnecessary to turn ON all the source-side or all the sink-side transistors. The leakage in the motor can be detected without misinterpreting noise on the battery-side as viewed from the inverter.

Abstract: An electronically controlled accessway includes a touch pad mounted to or immediately in front of, a door panel. A step plate is positioned immediately in front of the door. A user stands on the step plate to open the door and contacts the touch pad. A grounding sensor coupled to the touch pad and the step plate detects resistance between the touch pad and the step plate. If the resistance between the touch pad and the step plate is within a designated range, the grounding sensor releases an electronically controlled locking mechanism to permit the door to be opened. If the grounding sensor detects that the person is not properly grounded, the grounding sensor leaves the locking mechanism engaged to prevent the person from entering the statically sensitive area. In one embodiment, the door panel is pivotable about conventional hinges and the touch pad is integral to the door handle.

Abstract: A device is provided for measuring the voltage and energy between the contacts of a male connector from a piece of electronic equipment after it has been disconnected for a given period of time from a source of AC power. The device has both a voltage meter and a milli-joules meter which are connected into any one of a series of four circuits. In the first circuit, the meters are connected across the high voltage contact and the low voltage contact of the male connector. In the second circuit, the meters are connected across the high voltage contact and the safety ground, in the third circuit the meters are connected across the low voltage contact and the safety ground, and in the fourth circuit the meters measure the residual voltage and energy between the tip of a conductive probe and safety ground. A control element controls a relay to connect or disconnect the meters into the circuit selected after the piece of equipment being tested has been disconnected from a source of power for a given period of time.

Abstract: A coupling circuit receives a high voltage surge wave and injects it into e or more power lines of a single-phase or three-phase power supply circuit, either line-to-line or line-to-ground. The coupling circuit may have a surge coupler including a series connection of a gas tube and a coupling capacitor, and preferably a rectifier, and a shunt resistor for discharging the coupling capacitor. A one-stage or two-stage surge back filter across the power lines protects the power source from the surge wave. Each surge back filter may have series inductors, and shunt surge suppression circuits, which may each include a series combination of a capacitor and a resistor, in parallel with at least one metal-oxide varistor (MOV) or a cluster of MOVs. A grounding suppressor connected from a power line to ground may include gas tubes and/or MOVs, inductors and resistors. Risetime adjusting circuits including resistors and capacitors may be connected between the power lines and/or between the power lines and ground.

Abstract: A system for indicating fault condition on operator's electrostatic discharge protection equipment includes for an operator wearing ESD protection equipment comprising: a conductive wrist-strap in electrical contact with the operator's body, and an electrical wiring to a local ground, a portable system to alert the operator when a problem (cut or poor electrical connection) occurs with wiring to the ground, or when an electrical field reaches a predetermined value at the operator's wrist.In one embodiment, the invention also includes a device for memorizing that an ESD event has occurred.

Abstract: A pulse detection and conditioning circuit senses and conditions commutation pulses produced by a DC permanent magnet motor to determine motor position. The pulses are sensed using a resistor coupled in series with the motor, so that motor current and the included pulses are continuously sensed, even during motor braking. The serially coupled resistor also provides for sensing and conditioning of pulses of both polarities produced by bi-directional operation of the motor. The pulse detecting and conditioning is performed by circuitry which performs amplitude qualification as well as frequency filtering to effectively detect valid commutation pulses to the exclusion of noise and other unwanted signals. Capacitors coupled to the motor and internal capacitors provide the frequency filtering, while the amplitude qualification is provided by a balanced differential gain stage coupled through an adjustable differential gain stage with adjustable gain to a unity gain comparator.

Abstract: A circuit tester comprising a ground fault circuit interrupter having two pair of leads connected to opposite sides of the interrupter in series for connecting the ground fault interrupter between an electrical circuit and a power source to indicate current leakage in an amount greater than about 0.005 amperes, a method for utilizing the circuit tester for detecting amperage leakage in the circuit, and an electrical circuit which will be interrupted whenever there is ampere leakage above that magnitude.

Abstract: A method is specified for detecting ground faults on the conductors of electrical machines, in which method the fault resistance (Rf) is directly calculated in a numerical evaluation unit (7) from the injected (Ui) and the measured (URE) voltages. Since the fault resistance is explicitly calculated and displayed, it is independent of influences from the ground reactance. Moreover, there is no need to, for each machine, characteristics for drawing conclusions on the fault resistance. Moreover, the influence of ageing, temperature fluctuations, injection level fluctuations etc. is eliminated due to the numerical calculation. (FIG.

Abstract: A ground detecting method for an inverter unit and an apparatus for carrying the method into practice and which zero-phase current is detected on the basis of the output current from the inverter unit. A first value is added whenever the zero-phase current exceeds the ground level. When the added value reaches a predetermined value, it is judged as being the ground level. Further, when the zero-phase current is smaller than the ground level, a second value smaller than the first value, which is added whenever the zero-phase current exceeds the ground level, is subtracted from the added value.

Abstract: A test instrument for determining whether an apparatus has a high voltage on the chassis thereof includes a meter, a probe and a socket for receiving a plug from the device being tested. The device also has a plug for insertion into an AC outlet. The test device first tests to determine that the AC outlet into which it is plugged is properly configured, then tests for a voltage on the chassis of a tested apparatus. The test is undertaken by connecting both the high and low contacts of the plug from an apparatus to be tested to the high voltage side of an outlet and connecting the probe to the ground contact of an outlet. Thereafter, when the probe is touched to the chassis of the apparatus the meter will indicate whether a voltage is present on the chassis of the appliance.

Abstract: A device for testing for leakage of electronic equipment has a female AC connector for receiving the male AC connector of the electronic equipment to be tested and a male AC connector for attaching the test device to a source of AC power. The device also includes an electrically conductive probe and a meter for detecting a voltage on a surface contacted by the probe. Within the device are first and second switches which connect the male AC connector and the female AC connector in four successive configurations for applying AC power to the connector of the piece of equipment to be tested. A sequencing circuit in the device operates the two switches to apply all four test configurations within an interval of 1.033 seconds. The probe and the meter for detecting a current in the probe is used to contact the conductive surfaces of the piece of equipment being tested to detect a voltage while the four tests are applied to the power connector.

Abstract: Loads, such as power relays controlling wipers, windows and lights are connected to an automobile battery through individual transistor drives that are controlled by a microcontroller. A switch, connected to the microcontroller, is operated to activate each drive. The microcontroller checks the load characteristic when each drive is activated and inactivated. When the load is inactivated, it is part of a resistance network producing a test voltage that is digitally converted and supplied to the microcontroller, which compares the test voltage to a stored voltage to determine if the load is correct. An analog multiplexer is controlled by the microcontroller to select the voltage produced for each load.

Abstract: Provided is a method and circuit for measuring the leakage path resistance in an electric vehicle having an isolated high voltage traction battery and an auxiliary battery grounded to the vehicle. The circuit operates by periodically applying a selected excitation signal and comparing the voltage induced on an energy storage element by the excitation signal to a selected reference voltage during a selected time period. An alternate embodiment of the present invention provides a circuit which operates by applying a periodic excitation signal and comparing the phase shift of the voltage induced on an energy storage element to the phase shift of a signal derived from the excitation signal.

Abstract: Disclosed is a ground fault detection apparatus for an operating, normally ungrounded supply system, the apparatus having a periodically grounded center tap of a test impedance that is connected across conductors of the system, and detector circuitry including a charge balance circuit having low gain and wide dynamic range that measures the amplified voltage output of a Hall effect current sensor. A preferred implementation of the circuit has a charge transfer variable oscillator. A pair of microprocessor-controlled counters that are responsive to the oscillator precisely measure the average frequency of the oscillator over intervals that are automatically maintained at approximately one second in duration, the microprocessor calculating the fault current as the difference between current measurements taken with and without the center tap grounded.

Abstract: An electrical generator inspection system comprises an electro-magnetic core imperfection detector that provides an analog signal representative of fault currents detected between adjacent laminations of a stator core; an analog-to-digital converter coupled to the detector for converting the analog signal to a digital signal; a digital filter coupled to the output of the converter for digitally filtering the digital signal to remove noise therefrom; and means for storing predetermined signal criteria and for comparing the filtered digital signal to the predetermined criteria to determine the location of the insulation defects along the stator core. In one embodiment, the system further comprises means for storing the filtered digital signal in a memory.

Abstract: A fault detection circuit for a plurality of DC loads uses a reference load as a benchmark. The voltages at the centerpoints of the loads to be monitored are monitored and compared with the voltage of the centerpoint of the reference load. The comparison is affected by faults which do not affect all loads equally (as by a short or open) and is unaffected by faults which do affect all loads equally (as by changes in voltage of the source).

Abstract: A reference AC signal having a frequency of about 4-10 Hz is injected into a line of a DC electrical network for performing insulation measuring in a processing unit. The AC signal is measured in a mixed bridge having a first resistive dividing bridge connected in parallel with a second capacitive dividing bridge between the line and the ground. The intermediate output points of the first and second bridges are joined together and connected in an input of the processing unit. The impedance and the dividing ratio of the two bridges cause the DC voltage measured at said input to be low in relation to the value of the AC voltage measured at the output of said mixed bridge.

Abstract: An isolation monitor is electrically connected between the earth and an isolated neutral of a transformer which supplies AC electrical power to the main distribution network. In order to measure and to locate an isolation fault occurring somewhere on the feeders, each feeder is equipped with a toroid current measuring transformer, and comprises further a secondary winding connected to a processing locator performing synchronous demodulation. Two first and second transmission lines are provided between the isolation monitor and the locator. The first synchronous line transmits synchronization pluses from the monitor to the locator, and the second line transmits to the locator the demodulated values of the input voltage furnished by the monitor.

Abstract: A fault detection circuit for a plurality of three-phase loads uses a wye-connected reference load as a benchmark. The voltages at the centerpoints of the loads to be monitored are monitored and the largest monitored voltage is identified. This largest voltage is compared with the voltage of the centerpoint of the reference load. The comparison is affected by faults which do not affect all loads equally (as by a short or open in one of the phases of one of the loads) and is unaffected by faults which do affect all loads equally (as by changes in voltage of one of the phases of the source).

Abstract: A method and apparatus for testing handheld soldering irons having a three wire soldering tip by touching the soldering iron tip to a single point sensor to measure tip temperature, tip voltage to ground the tip resistance to ground. A thermocouple sensor for use with a soldering iron testing apparatus is described.

Abstract: A ground integrity monitor for testing for a short circuit between two equipotential ground planes having a single common connection point includes an AC generating circuit for coupling to one of the ground planes a signal having predetermined frequency and magnitude characteristics. An AC detecting circuit coupled to the other of the ground planes is adapted to detect the AC signal within a predetermined range of magnitude and frequency. Presence of the signal on the other ground plane indicates the existence of a short circuit.

Abstract: A digital isolation monitor comprises a digital processing signal processor P1 designed to synthesize a sine wave in real time by a table, and to send the digital values of this sine wave to a digital-to-analog converter of an input channel to generate a low-frequency AC reference signal with a very low, stable phase distortion factor. An acquisition channel is fitted with a switching unit operating in conjunction with a dual measurement circuit to send an injected voltage signal and a leakage current signal to a low-pass analog filter in series with a sample-and-hold circuit and an analog-to-digital converter. The processor P1 then performs synchronous demodulation and transmits the data to a microcontroller P2.

Abstract: The apparatus for monitoring and controlling electrostatic discharge control systems provides an automated sequence of electrostatic discharge control and soldering iron performance measurements that can be used to verify the continued integrity of the electrostatic discharge control systems. This is accomplished by a microprocessor controlled central data acquisition and control unit that controls a plurality of test units. Each work station in the manufacturing environment is equipped with a test unit that performs a number of measurements and tests of various electrostatic discharge control systems and soldering iron performance. The central data acquisition and control unit sequentially and automatically polls each individual test unit to perform or prompt the operator to participate in the designated measurements. The data obtained by each test unit is transferred to the central data acquisition and control unit where the data is analyzed and recorded.