Abstract: A trip device comprising a differential current detection transformer, a trip relay of a breaking mechanism of the circuit breaker and a test circuit for checking the operation of the trip device. The relay comprises a fixed yoke bearing a coil and a blade that is mobile with respect to the yoke. During normal operation of the trip device, the blade is held magnetically in the position pressing against the yoke and when a differential current occurs, the blade actuates the breaking mechanism. The test circuit generates a vibration of the blade, without causing tripping of the mechanism, in order to check its ability to disengage from the fixed yoke. Advantageously, this vibration is obtained by application of a voltage in the form of pulses to the terminals of the coil.

Abstract: The apparatus detects subsidence current from unfiltered as well as filtered secondary current values in the current transformer. A lack of zero crossings during a predetermined period is a reliable indication of the presence of subsidence current. If subsidence current is detected, then a signal is generated which indicates that the circuit breaker for the power system has opened, providing an accelerated indication thereof relative to an indication produced by an overcurrent element dropping out.

Abstract: An electrical distribution system having a load center for programmably and remotely controlling a plurality of circuit breakers, an expander unit coupled to the load center and a plurality of external switches for providing signals to the load center representative of the status of the switches. The load center contains a control module that continually receives inputs from the expander unit via an interface module. It also contains a keyboard and display for programming instructions for closing and opening the individual circuit breakers and for displaying the status of the circuit breakers. The interface module, coupled to the control module, causes the circuit breakers to open and close according to programmed instructions received from the control module or another external device. The expander unit contains a plurality of input circuits coupled to external switches.

Abstract: A plurality of monitoring devices are connected to respective pieces of switchyard equipment and associated with a common communications network. A remote host computer is connected to the network to bidirectionally communicate with each monitoring device. The communications network is the existing power line used for delivering power and control signals to the switchyard equipment. Each monitoring device includes testing and/or monitoring circuitry for testing and/or monitoring one or more conditions of the piece of switchyard equipment and generating condition data therefrom, a storage device for storing the generated data, and a transmitter adapted to transmit the data to the remote location via the power line. The remote host computer receives the data transmitted to the remote location and stores the received data therein in a database format. The monitoring device can request previously sent data from the remote host computer.

Abstract: An apparatus for demonstrating and testing the operation of an arcing fault detector. The apparatus comprises an electrical circuit including line and neutral conductors connected between a power source and a load. A selector switch is movable between a first position and a second position in order to selectively route load current across either an arcing fault detector or standard circuit breaker. A pair of electrodes is positioned between said selector switch and the load for producing an arcing condition on the line conductor.

Abstract: The invention relates to a method of protecting against circuit breaker failure, said circuit breaker having contacts capable of moving between a closed position and an open position, and vice versa, and being fitted with protection apparatus including fault detector apparatus for putting into operation an opening electromagnetic coil that actuates circuit breaker contact drive apparatus, with position-indicator contacts of monitor apparatus being changed over as soon as the circuit breaker contacts start to move. According to the invention, in the event of a fault being detected, a time delay is generated from the indicator contacts changing over, and at the end of said time delay it is verified whether the fault current has become zero, and if not an alarm is generated.

Abstract: A relay test apparatus for testing a protective relay operation of a protective relay system comprises GPS receivers, respectively connected to the protective relays, each GPS receiver analyzing time data included in a signal transmitted from a satellite and outputting a time signal, simulation signal generators, respectively connected to the protective relays, each simulation signal generator generating a simulation signal and inputting the simulation signal to a corresponding protective relay, and synchronous starting units, respectively provided in the protective relays, each synchronous starting unit starting a corresponding simulation signal generator to generate the simulation signal, when time signals output from the GPS receivers coincide with a preset time at a same time.

Abstract: A system and method for automatically testing the operation of a protective relay system is disclosed. The system and method provide for continuous testing to ensure proper operation of the protective relay system while the relay remains in service and without interrupting the normal operation of the relay. This testing is performed by storing reference data corresponding to test signals, generating test signals, sampling a specific test signal, processing that test signal through the relay and comparing the processed test signal with the corresponding reference data. Upon detection of an error in the relay, the system and method further provide for isolation of the relay from the electric power system and automatic testing of individual electrical components within the protective relay system to determine the identity of the malfunctioning component.

Abstract: A circuit breaker tripper includes a first charging circuit for charging an RC shorting time control circuit. A relay is connected to a pair of probes that are connected to an active line which enables a charging of the RC shorting time control circuit. Activation of a switch causes a relay to apply a short circuit across the active line, thereby causing a tripping of the circuit breaker. At the same time, a discharge circuit is activated which causes the relay open the short circuit after a preset period. Since the circuit breaker tripper relies on enabling sufficient current flow through the circuit breaker to trip it, a test circuit is provided which enables operation of the tripper only if the branch circuit is within a safe operating range for the circuit breaker tripper.

Abstract: Coordination of the overcurrent/time trip characteristics of a hierarchy of overcurrent protection devices is accomplished through a central tester which establishes a pattern of test currents for the individual overcurrent protection devices which simulates a fault at a specified location in the power system. The individual assigned test currents are transmitted over a communications link to the separate overcurrent protection devices where they are stored in memory. The central tester then broadcasts a test signal which simultaneously initiates testing of all of the overcurrent protection devices using the assigned test currents stored in memory. The trip times are recorded and reported back to the central tester for analysis.

Abstract: A bell alarm system is provided for a circuit breaker in which the actuation of a flux shift trip device causes an electrical switch to be energized thus providing a bell alarm indication that the circuit breaker has been tripped. The flux trip device impinges against a pivotally rotated lower lever mechanism which has a knee which causes rotation of an upper lever against the influence of a spring attached between the two levers. As the knee moves along a surface of the upper lever mechanism, the relative rotation of the two lever members about their support pins is such as to cause the tension on the spring to increase. Because of this vibration in the circuit breaker itself or minute low level movements of the plunger mechanism will not cause the bell alarm to be actuated.

Abstract: A circuit breaker testing apparatus includes an electrical circuit, an adjustable inductor connected in the circuit and a transducer for sensing current flow in the circuit. The circuit has leads terminated by electrical connectors for connection to terminals of a circuit breaker for providing a source of electrical power to circuit from the circuit breaker. The inductor is adapted to produce an adjustable electrical load on the circuit breaker. The testing apparatus also includes an indicator connected to the transducer for producing a reading of the magnitude of current flow in the circuit and for displaying and holding the reading of the highest magnitude of current flow reached in the circuit and thereby the magnitude of current flow at which the circuit breaker is tripped by the adjustment of the electrical load on the circuit breaker.

Abstract: A relay test apparatus for testing a protective relay operation of a protective relay system comprises GPS receivers, respectively connected to the protective relays, each GPS receiver analyzing time data included in a signal transmitted from a satellite and outputting a time signal, simulation signal generators, respectively connected to the protective relays, each simulation signal generator generating a simulation signal and inputting the simulation signal to a corresponding protective relay, and synchronous starting units, respectively provided in the protective relays, each synchronous starting unit starting a corresponding simulation signal generator to generate the simulation signal, when time signals output from the GPS receivers coincide with a preset time at a same time.

Abstract: A method and apparatus for measuring and recording peak RMS electrical current over multiple moving-average time periods provides current-flow information in the same units used to characterize electrical system distribution components--primarily overcurrent protective devices such as fuses and circuit breakers. Rather than reporting current-flow information based on a series of brief observations of a few line cycles or seconds, short duration RMS current-flow information in multiple geometrically increasing time intervals is calculated and accumulated to form longer duration RMS values of current. The resulting set of peak RMS current-flow values properly characterizes both the long and short term heating effects of the electrical current in the circuit under inspection, and is used in direct side-by-side comparisons with manufacturer provided data for specific distribution components in the evaluation of usage versus capacity and other functions relevant to distribution system design.

Abstract: A device for measuring circuit breaker wear by integrating the square of the current to be interrupted, said circuit breaker including a control that is actuated by a trip coil. The device includes a timing delay circuit that is actuated by a signal corresponding to a change in the driven or non-drive state of the trip coil, the timing delay circuit causing integration to begin after time has elapsed that is equal to the mechanical delay of the circuit breaker, which mechanical delay is a previously-measured data item. The device further includes a circuit that delivers a signal proportional to the current carried by the circuit breaker, a circuit that squares the signal, and that applies said square to the integrator, said integration being performed for a given length of time that is longer than the maximum arcing time of the circuit breaker, which maximum arcing time is likewise a previously measured data item, the result of the integration being applied to a summing circuit.

Abstract: A relay test apparatus for testing a protective relay operation of a protective relay system comprises GPS receivers, respectively connected to the protective relays, each GPS receiver analyzing time data included in a signal transmitted from a satellite and outputting a time signal, simulation signal generators, respectively connected to the protective relays, each simulation signal generator generating a simulation signal and inputting the simulation signal to a corresponding protective relay, and synchronous starting units, respectively provided in the protective relays, each synchronous starting unit starting a corresponding simulation signal generator to generate the simulation signal, when time signals output from the GPS receivers coincide with a preset time at a same time.

Abstract: A sensitive to a change in the physical dimension(s) of the exterior surface of a pressure vessel transducer and attached to the exterior surface thereof the pressure vessel may be a vacuum chamber. The transducer measures exterior dimension change, representing interior pressure change information, without intrusion. The measurements are displayed using distinctive lights or audible alarms which signal if the pressure inside the vessel is within a predetermined range. If the pressure within the vessel varies outside of the predetermined range, a more precise display device such as a meter, is provided to aid facility personnel in deciding when repairs are necessary.

Abstract: A molded case circuit breaker containing a digital trip unit is field-tested for both electronically-induced as well as mechanically-induced test conditions by means of a portable test kit unit. The test kit circuit components are contained within a miniature test plug that temporarily connects with the circuit breaker trip unit by insertion within the rating plug receptacle formed within the circuit breaker cover. A compact power supply plug is received within the test plug to provide operating power to the circuit breaker trip unit components and associated accessories.

Abstract: The terminals of a test circuit are directly connected to outputs of the transformer secondary windings and to the input of the rectifying circuit so that the test current checks operation of the trip device. A sign detection circuit supplies a processing circuit with the values of the polarities of the rectified currents. The processing circuit comprises means for determining the presence of a test current when the sign of the rectified current comprising the test current remains continuously in the same polarity. A differentiation of the continuous polarity, positive or negative, of the test current enables testing to be carried out with or without earth protection tripping.

Abstract: This invention permits one to trace more than one electrical conductor, each of the electrical conductors being associated with both a circuit breaker and an electrical outlet. The invention consists of a receiver and multiple transmitters. Further, in a single transmitter form of the invention, the invention permits the transmitter to continually transmit its signature signal without power dissipation concerns, just like the ability to continually transmit in the multiple transmitter form of the invention. Lastly, the device is able to trace conductors regardless of the load electrically connected to the conductor.

Abstract: An improved vacuum valve including an insulating container and an arc shield held in the insulating container, wherein a protrusion is formed on either the outer cylindrical surface of the arc shield or on the inner surface of the container. A detecting electrode is set confronted with the outer surface of the insulating container with an air gap therebetween, and is grounded through a current sensor. The current sensor detects a discharge current which is induced through the protrusion when the degree of vacuum of the vacuum valve is reduced, to output a detection signal. In response to the detection signal, a signal processing unit outputs an alarm signal indicating the reduction in the degree of vacuum of the vacuum valve. Thus, while the vacuum valve is in operation, its vacuum reduction can be positively detected with the vacuum valve maintained unchanged in reliability.

Abstract: A circuit breaker locator comprises a housing having a plunger projecting outwardly at one end and reciprocably moveable within the housing. The plunger is coupled to a spring urged retractable contact at the opposite end of the housing. The housing also includes, at the end with the retractable contact, a pair of contacts extending outwardly therefrom which are coupled to a fuse and a pilot light connected in parallel with the fuse. In operation, the pair of contacts are inserted into an electrical outlet and the plunger is actuated forcing the retractable ground contact into the outlet. The device automatically trips a circuit breaker related to the particular outlet so that it is possible to check which circuit breaker is connected to the outlet. If the breaker fails to trip, the alarm light, which is connected parallel with the fuse, is activated indicating a faulty circuit breaker. The circuit breaker locator provides a ready and safe means of determining what circuit breaker is related to what outlet.

Abstract: A ground fault circuit interrupter (GFCI) circuit breaker test circuit for use with panelboards uses a selector switch, normally open switch, and a resistor to simulate a fault condition at the load output node of any one of several GFCI circuit breakers. This arrangement allows for testing of the circuit breakers while eliminating the need to use an external test actuator to operate the manual test button of each circuit breaker. Thus, shaft penetrations through the panelboard enclosure are minimized, resulting in reduced hazards, increased reliability, easier testing, and greater economy.

Abstract: A microprocessor based switch such as a circuit breaker has a memory capacitor charged by the microprocessor to generate an analog equivalent of a digitally modelled heat state signal. A selected resistor discharges the capacitor at a rate which models a cooling rate of a load. Alternatively, the memory capacitor may be charged to a preset value and discharged at a rate representative of the time since a trip generates digital rms representations of analog load. Terminals for rapidly resetting the analog trip memory for calibration and field testing of a long delay trip are hidden behind a removable rating plug.

Abstract: A vacuum circuit-breaker including, for each phase, at least one vacuum bottle housed inside a closed enclosure, wherein said circuit-breaker includes at least one scintillation fiber disposed in the space between said enclosure and the outside surface of the vacuum bottle(s), said fiber being connected outside the circuit-breaker to an opto-electronic device.

Abstract: A portable field tester for a circuit breaker having an electronic trip unit includes a ribbon cable having a connector plug for making connection to a restraint plug socket of the trip unit. The tester has a parallel connector in which the breaker rating plug may be inserted. A battery source is included and a battery fail LED is illuminated if the source voltage falls below a certain level. A voltage regulator and a plurality of voltage dividers develop reference test voltages for application to the breaker trip unit via the connectors and cable. Switches selectively disable a ground fault test circuit in the breaker during primary injection testing. A pair of resistors are connected via the cable and connectors for rapidly discharging the breaker memory circuits after each test.

Abstract: The operation and functioning of various elements in a circuit breaker panel assembly are monitored and tested using a permanently installed or a portable test module that can be plugged into a plug-in jack on the housing of the circuit breaker panel assembly. The test module includes readout elements, data recording elements as well as telemetry networks for relaying data to a central station where such data can be reduced, recorded and analyzed by experts. The circuit breaker panel can include a voltage surge and transient protection network. A method of monitoring and testing is also disclosed.

Abstract: The operation of energized substation circuit breakers in electrical power distribution systems is directly monitored. For each circuit breaker in a multi-phase breaker arrangement, the flow of electrical current is sensed. A signal is then formed for each phase representative of the sensed current flow. The signals so formed for the multi-phases are combined into a composite waveform for monitoring and diagnostic purposes. In the composite waveform, the signal for each phase of the circuit breaker is identifiable by its time relationship to others and by a distinctive voltage level.

Abstract: A system and method for detecting partial discharge of gas-insulated switchgear wherein a high-frequency component and the fundamental wave component of the voltage applied to the conductor of the gas-insulated switchgear are detected, the zero-cross point of the fundamental wave component is set as the starting point for the voltage, and the presence of partial discharge and the reason for the occurrence of partial discharge are ascertained based on the phase difference between the phase of the detected high-frequency component and the phase of the starting point of the voltage.

Abstract: Disclosed is an electromagnetic wave shielding material comprising a flexible base fabric, a first metallic film formed by flame-spraying a metal such as zinc on one side of said base fabric and a second metallic film such as an aluminum foil formed on the other side of said base fabric; said first metallic film does not peel after long lapse of time and can provide sufficient shielding effect to be used in unechoic chambers etc.

Abstract: A device for testing support equipment for a power circuit breaker, including a breaker simulator for simulating a power circuit breaker, a connector for connecting the breaker simulator to a breaker control panel, and a switch for re-directing the functions of the breaker control panel to the simulator.

Abstract: The invention relates to a synthetic equivalent test circuit which can generate a 4-parameter transient recovery voltage TRV, for verifying a large current breaking performance of a power circuit breaker. A current source current is supplied to only a testing circuit breaker which is to be tested and an auxiliary circuit breaker. A small current with respect to the current source current is transmitted to the first and second auxiliary switches from a power source. When the small current form the current source or the resonance circuit flows, the first auxiliary switch is opened almost simultaneously with the auxiliary circuit breaker, the testing circuit breaker and operates so as to break the current at the time point of the final zero point of the current source current.

Abstract: Portable testing apparatus for low current circuit breakers which enables short circuit and constant current tests to be conducted at the breaker panel. A first container includes a parallel array of resistive loads each under control of a corresponding relay. Low voltage control circuitry is provided in a second container and permits variation of the load appearing in series with the circuit breaker under test. The short circuit test can be performed at the first container which operates at the line voltage.

Abstract: A circuit breaker monitoring system for monitoring three-phase circuit breakers includes three channels that convert a respective phase current through a respective set of circuit breaker contacts into a sequence of digital signals each representative of an instantaneous value of current through the contacts. Each channel includes a transformer having a primary winding that receives current corresponding to that through the breaker contacts. A resistor across the secondary winding develops a voltage proportional to the current. An input buffer voltage follower couples this voltage to the input of a high-speed 12-bit bipolar analog-to-digital converter that provides the digital signals. A microprocessor coupled to a 12K RAM working memory, a 4K EPROM that may store breaker monitor software and a 2K E.sup.

Abstract: A method and apparatus for adjusting a bimetal trip element. The object is to provide a method to adjust bimetal trip elements for electric switching devices, which produces a reliable result in a standard number of adjustment steps. Based on the measurement of the path that a tripping shaft travels until the latching is released and of the force required for this, a processor computes a value, which is used to set-up an adjusting screw. Subsequentially, when the bimetal strip is heated as a function of current, the time it takes the bimetal strip to travel until contact is made with the adjusting screws and also the total tripping time are determined. From these values, the processor computes a correction value to control a screwdriver which adjusts the adjusting screw. An auxiliary device contains a contact slide to incorporate the adjusting screws and the bimetal strips in a signal circuit, as well as a driving arrangement to move the contact slide.

Abstract: Output current of secondary winding of a current transformer (21) corresponding to current value of an A.C. power line (1) is led to series connection of an electric power circuit (500) and resistors (40,41); voltages obtained across the resistors (40,41) are input to a time delay circuit (70) which ignites a load break contact (200) in the A.C. power line (1) when an accident overcurrent flows in compliance with tripping characteristics. A quasi output signal or reference signal for testing of D.C. voltage is applied to the time delay circuit (70) when any current does not flow in the A.C. power line, thereby to enable tripping test of the circuit breaker as it is connected to the actual power line.

Abstract: An organo-platinum complex of the formula ##STR1## wherein X and Y have the same meaning of a halogen, oxyanion or carboxylate, respectively or X is an oxyanion or dicarboxylate together with Y, and L.sub.1 and L.sub.2 are bonded together to form one of silicon containing diamine compounds selected from the group consisting of ##STR2## in which R.sub.1, R.sub.2 and R.sub.3 are a lower alkyl or phenyl, respectively, and n is an integer of 0 or 1,and use of the complex for an anti-tumor composition.

Abstract: Disclosed is a switch operation monitoring apparatus for quickly and accurately detecting an abnormal operation of an actuating mechanism actuating a switch such as a power circuit breaker. A normal characteristic stroke of a moving part of the actuating mechanism is previously calculated on the basis of an interrupting current waveform, an environmental gas pressure and an actuating fluid pressure while taking into account the structure of the switch so as to use the calculated characteristic stroke as a reference stroke, and this reference stroke is compared with an actually measured characteristic stroke to decide whether the operation of the actuating mechanism actuating the switch is normal or abnormal.

Abstract: A test kit for a digital and analog electronic circuit breaker determines the calibration and overcurrent response of the circuit breaker when connected within an electric power circuit. The test kit simulates an overcurrent condition and provides verification of the circuit breaker response without de-energizing the circuit breaker or interfering with the circuit breaker's protection functions. The test kit connects with the digital communications circuit within the digital circuit breaker to obtain status information concerning pick-up conditions, trip conditions and fault currents which are viewed on the test kit liquid crystal display. A ground fault suppression circuit is included within the test kit for single-phase current-injection without causing ground fault tripping. The test kit circuit further includes means for optionally tripping the circuit breaker upon completion of any of the tests.

Abstract: The invention is directed to a portable test device for an electronic trip unit which is electrically powered from the internal power supply of the trip unit being tested. The test unit utilizes three leads connected to the trip unit. One of the leads connects to the voltage source for the trip unit and another lead connects to the ground potential to acquire power from the test unit. The voltage is selectively adjusted within the test unit by resistors and a potentiometer to vary the input voltage which is to be carried by the third lead into the trip unit.

Abstract: A method and apparatus for testing the operability of an overload protection device for an induction motor, rapidly and without the need to mechanically load the motor output shaft. A rectifier circuit converts a standard AC input power signal to an unfiltered full wave rectified output power signal which is applied to the input terminals of the motor under test to rapidly heat the overload device to its trip temperature. The output power signal is periodically interrupted for brief periods of sufficient duration to extinguish any arcing occasioned by the opening of the overload device contacts. The period between successive interrupt periods is selected to be short enough to extinguish any such arcing before the contacts are damaged. If the contacts of the protection device fail to open within a predetermined time period, a signal is generated to indicate that the overload device has failed to operate properly.

Abstract: A digital solid-state trip unit of an electrical circuit breaker is equipped with an electrical contact wear indicator enabling the degree of wear of these contacts to be known. Each time the circuit breaker performs a break, the microprocessor determines a contact wear value, in terms of the maximum value of the current broken. The correspondence between the wear value and the current broken is stored in a ROM memory and the successive wear values are added in a NOVRAM memory whose contents are representative of the degree of contact wear. These contents can be displayed to indicate to the user that the condition of the contacts has to be checked.

Abstract: A method for reclosing a temporarily opened circuit breaker in a manner which assures that generation of unwanted overvoltage stresses is avoided during the reclosure process. An oscillating line voltage typically develops in a shunt-compensated line after a circuit breaker connecting the line to a voltage source is opened. When the circuit breaker is reclosed the source voltage and the oscillating voltages must be properly phased to avoid the overstressing problem. In operation, the polarities of the feed voltage and the oscillating line voltage are detected and the instant when the circuit breaker may be reclosed is calculated. The periods T.sub.L and T.sub.S of the line voltage and the feed voltage are measured. Also measured is the time .DELTA.T which elapses from a zero crossing of the line voltage waveform to a subsequent zero crossing of the feed voltage waveform having the same phase angle as that of the line voltage zero crossing. The circuit breaker is reclosed upon satisfying the relationship:.

Abstract: Electronic trip units employed within static trip circuit breakers are individually calibrated and automatically adjusted to ensure that the trip transfer characteristics are within specification requirements. A trimming network within the trip unit circuit contains a plurality of parallel resistors each separately connected within the circuit by means of a fusible link. Test input and output values are compared to idealized values that are binary-weighted within a look-up table in the test equipment computer. The percent correction required is determined and the appropriate links are interrupted to provide ideal trip response.

Abstract: A method for and an apparatus for use in testing a circuit breaker, the circuit breaker having at least one current sensing means, such as a current transformer, trip circuitry, and circuit interruption means. In the method, a low voltage A.C. source is provided; and means for generating an A.C. signal is also provided, the means for generating an A.C. signal having the capability to vary the magnitude of the voltage of the A.C. signal. The low voltage A.C. source is connected with the means for generating an A.C. signal; and the means for generating an A.C. signal is connected with a current sensing means of the circuit breaker. The current sensing means is energized with an A.C. signal; and the magnitude of the current in the A.C. signal is monitored. The magnitude of the current in the A.C. signal and the state of the circuit interruption means in the circuit breaker is compared with a predetermined magnitude of A.C.

Abstract: A device for monitoring the condition of a high voltage circuit-breaker comprises as current-sensing members a number of reed contacts, which are located in such a way in relation to the current path through the circuit-breaker that the contacts are activated at different current levels. The reed elements control a pulse train to a counter, which takes place with different dignity for the different elements. With the aid of a position transducer connected to the contact device of the circuit-breaker, the pulse train is started simultaneously with the opening of the circuit-breaker, the contents of the counter thus being a measure of the contact wear. The contact position transducer is also used for measuring the opening speed, and if said speed falls below a certain value, alarm is triggered.

Abstract: A device is provided for generating an AC current ramp for checking the tripping current of the circuit-breaker, in which the current is regulated by a power transistor driven by the voltage available at the middle point of a potentiometric divider, this latter comprising a field effect transistor which is itself driven by a voltage depending on the voltage at the terminals of a capacitor charged by an auxiliary battery. It further comprises a constant current generator which is fed with current by the auxiliary battery for charging said capacitor and a comparator amplifier a first input of which is connected to said capacitor, a second input of which is connected to the junction point between a measuring resistor and said power transistor and the output of which is connected to the gate of said field effect transistor.

Abstract: A single pole circuit breaker comprising a single section. The single section, single pole comprises an electromagnetic sensing device and a pair of relatively movable contacts. The electromagnetic sensing device is electrically connected at one end to the load terminal. The movable contacts are engageable with a pair of stationary contacts carried by a line terminal. A metering or calibrating shunt device is connected on one side to the electromagnetic sensing device and is connected on the other side to the pair of movable contacts to thereby connect in electrical series the electromagnetic sensing device and the pair of movable contacts through the metering or calibrated shunt device. A volt meter connected across the calibration points of the metering or calibrated shunt device will then read a voltage proportional to the current flow through the circuit breaker.

Abstract: A programmable controller system is taught which uses an oscillator to provide a relatively low frequency low duty cycle series of digital ones and zeros to the gate logic of a load control device regardless of whether the device is in the ON or OFF state. These signals are electrically passed through the system which controls the load for such a short time that the load cannot change state because of electrical momentum and/or inertia thereof. The series of digital ones and zeros nevertheless do pass through the system and sensing means serve to test the correct operation of the output devices. As long as the oscillator generated signals continue to pass through the gate, the capacitor controlled sensing devices will be held in a state such as to provide no indication of failure.

Abstract: There is provided a novel vacuum detection means utilizing a high frequency, high voltage device to excite an electrical discharge in a vacuum whose characteristics are dependent on the level of the vacuum contained therein. This discharge current allows the degree of vacuum to be continuously monitored.