Abstract: Cycle error correction is performed in an electronic power system to compensate for a difference between an AC grid side frequency and an AC load side frequency. The electronic power system can comprise an electronic power inverter, such as one usable with an uninterruptible power supply. Cycles of signals indicative of the AC grid power and the AC load power are counted and compared to obtain a cycle error value. If the cycle error value exceeds a first value to indicate that AC load side frequency is too high or too low, then compensation is performed to change the AC load side frequency to be closer to the AC grid side frequency. If the cycle error value falls below a second value to indicate that the AC grid side frequency and AC load side frequency are sufficiently close to one another, then the compensation is deactivated.

Abstract: Power control circuitry is provided for controlling connection of a power source having a source voltage level to a switched power rail to provide power to an associated circuit block. The power control circuitry comprises a switch block for selectively connecting the switched power rail to the power source, and a switch controller for controlling operation of the switch block. A ring oscillator circuit is powered from the switched power rail and produces an oscillating output signal, and analysis circuitry is then used to analyse change in frequency of the oscillating output signal produced by the ring oscillator circuit during a period of time when the switched power rail is not at the source voltage level. The switch controller is then arranged to control at least one aspect of the operation of the switch block in dependence on the analysis. This technique provides a simple and effective digital technique for observing voltage changes on the switched power rail.

Abstract: A method and apparatus for an interface switch having an external terminal electrically connected to an AC voltage ? at a frequency ?0 (for example a utility supply), and an internal terminal electrically connected to an AC voltage V at a selectable frequency ? (for example a microsource). In one embodiment, the interface switch is closed when the voltage difference between ? and V and the relative phase angle ?EV between ? and V are both small, and when the higher frequency voltage (as between ? and V) leads the lower frequency voltage. In another embodiment, the interface switch is closed when the envelope of the voltage difference between ? and V reaches a local minimum at a point of inflection.

Abstract: An apparatus to generate a high voltage includes a switching part to control a voltage induced in a secondary coil of a power transforming part, by interrupting a current in a primary coil of the power transforming part, a digital controlling part to control the interruption operation of the switching part according to supplied control data. The switching part, the digital interfacing part and the digital controlling part may be embodied in an ASIC chip (application-specific integrated circuit). An optimum control according to an output state of the apparatus is easily achieved, manufacturing time for tuning each parameter is reduced and heat generation in the apparatus is reduced.

Abstract: An integrated circuit includes a storage component, a voltage stabilizer circuit with an input configured to receive an input voltage and an output configured to provide an output voltage, and a load. The load is coupled to the output of the voltage stabilizer circuit. The integrated circuit is operable in a first and second operating state. In the first operating state, the storage component receives an input voltage and in the second operating state the input voltage is provided to the input of the voltage stabilizer circuit.

Abstract: A method and apparatus for providing isolated high and low direct current power supplies to a Power Device using a sealed high Power Device Gate Driver having a single transformer, wherein the Gate Driver integrates the power supplies, gating control and gate control, gate drive and Power Device diagnostics into a sealed unit, wherein the unit may be further sealed hermetically.

Abstract: A method for detecting and interrupting an electrically islanded condition for a grid connected current source inverter is disclosed in which: A line voltage frequency is monitored at a cycle or sub cycle resolution. Current output from the inverter is periodically phase shifted. If voltage is observed to follow the phase shift of the current output an islanding error signal is generated causing the inverter to stop injecting power onto the line.

Abstract: An electric circuit for capacitive sensor elements of a touch switch can be designed as a switch capacitor circuit and van be provided with a micro controller. The sensor elements are provided in sensor branches with a charging capacitor. In addition, a reference branch is provide. It contains a reference capacity and a reference charging capacitor, which have capacities that correspond to those of the sensor branches. By comparing the number of charge transfer processes required to reach the switching threshold in the sensor branch and the reference branch, fluctuations of the supply voltage, and consequently the switching threshold itself, can be compensated for.

Abstract: A remote controlled power switch system includes a transmitter (10) having selection elements and emitting different controlling signals each having a predetermined frequency corresponding to different responses of the selection elements; and a number of receivers (11, 12, 13) each adapted to switch an ON/OFF state of an electrical load under control of the corresponding controlling signal transmitted from the transmitter. The switched receiver transmits a feedback signal to the transmitter after receiving the controlling signal. The transmitter has an indicator unit (106) for indicating the receiving of the feedback signal. The indicator unit comprises an LED light (400) for indicating the ON or OFF state of the switched receiver by emitting different color of lights, a number of LED lights (401, 402, 403) for indicating which of the receivers is switched on, or a display (404) for showing a designated number of the switched receiver.

Abstract: A method for detecting line under frequency (LUF) events and initializing load shedding of loads located near the electrical disturbance without customer and utility intervention is disclosed. In one example embodiment, the LUF detection system measures the time period of each power line cycle and then compares the measured time period to a utility-configurable trigger period. If the cycle length is greater than or equal to the trigger period, a counter is incremented. If the cycle is less than the trigger period, the counter is decremented. If the counter is incremented to a counter trigger, an under-frequency condition is detected and the LUF response either controls the load or temporarily disconnects it. A restore response is initialized after the frequency rises above a restore value and an under-frequency counter counts down to zero.

Abstract: A switch (10) comprises a face plate (16) and a single switch sensing oscillator (18) responsive to a switch activating presence. The oscillator (18) has a resistive component (36) connected to a sensing plate (38) which acts as a first capacitor plate. The face plate (16) is arranged to prevent electrical contact between the user and the oscillator (18). Any object, when placed adjacent the face plate (16), acts as a second capacitor plate which alters the frequency of the oscillator (18). A microprocessor (20) senses the smoke detector (62). In a further aspect the switch includes a mains electricity cable signal transmitter/receiver and a microprocessor whereby each such switch may communicate directly with another such switch.

Abstract: One embodiment of the present invention provides a system that facilitates selectively increasing the operating frequency of an electronic circuit, such as a computer system. The system begins by operating in a low-power state with the frequency and voltage of the electronic circuit set to low levels. Upon recognizing the need for performance beyond the low power level, the electronic circuit enters the first-intermediate power state. In this first-intermediate power state, the frequency and voltage are set to first-intermediate levels. Upon recognizing the need for performance beyond the first-intermediate power state, the electronic circuit enters the maximum-sustainable power state. In this power state, the frequency and voltage are set to maximum sustainable levels. Upon recognizing the need for performance beyond the maximum-sustainable power state, the electronic circuit temporarily enters a boosted power state beyond the maximum-sustainable power state.

Abstract: An Automatic Transfer Switch System includes a control circuit in which high frequency transformers, designed to operate linearly in a frequency range above the operating frequency range of utility-level power, are employed for voltage sensing. An output signal from a high frequency line matching transformer is received by a microprocessor which evaluates the signal for both a voltage level and frequency and uses these values as indices to an empirically-derived look-up table which provides an actual voltage level to the microprocessor. The actual voltage value can then be evaluated by the microprocessor to determine if and when the power delivered to a load should be supplied by a first or a second power supply.

Abstract: A closing phase that produces the smallest energization flux error at a connection input point is calculated based upon a residual flux of the first closing phase and the preliminarily given pre-arc characteristic and closing time deviation characteristic of a three-phase circuit breaker, so that the calculated phase value is set as a target closing phase of the first closing phase. A closing phase that produces the smallest energization flux error when a residual flux of zero is calculated, so that the calculated phase value is set as a target closing phase of the remaining two phases. The total time required from the reference point to the target closing phases of the remaining two phases and a delay time corresponding to an integer multiple of a given cycle of the three-phase power supply is set as a target closing time of the remaining two phases.

Abstract: An automatic transfer switch (ATS) controller is disclosed which includes a power supply circuit to regulate and filter input power, a transformer to convert utility and generator power sources into power supply voltages and voltage sensing sources and a voltage sense signal conditioning circuit. Controller further implements a solenoid driver circuit to drive automatic transfer switch solenoids, an embedded microcontroller configured to monitor utility and generator voltages and a user interface interfaced to said microcontroller for operator entry of instructions. A LED indicator is included and is configured to verify user interface entries and overall operation of the controller and ATS system.

Abstract: An electric circuit for capacitive sensor elements of a touch switch can be designed as a switch capacitor circuit and van be provided with a micro controller. The sensor elements are provided in sensor branches with a charging capacitor. In addition, a reference branch is provide. It contains a reference capacity and a reference charging capacitor, which have capacities that correspond to those of the sensor branches. By comparing the number of charge transfer processes required to reach the switching threshold in the sensor branch and the reference branch, fluctuations of the supply voltage, and consequently the switching threshold itself, can be compensated for.

Abstract: The present invention provides a method and apparatus for alternating current (AC) power failure detection. The method includes amplifying an AC power waveform, where the amplified waveform is asserted when the AC power waveform is in a vicinity of a zerocrossing and negated at all other times; initiating a counter when the amplified waveform is asserted; and determining if the counter equals or exceeds a reference number, where the counter being equal or exceeding the reference number indicates an AC power failure. The present invention converts an AC power signal to a near digital signal, where the near digital signal is asserted when the AC power signal is in the vicinity of a zero-crossing and negated at all other times. When the near digital signal is asserted, a counter in a controller begins counting, and ends the counting when the near digital signal is negated.

Abstract: A pulse signal transmitting circuit generates a pulse signal having an enhanced high-frequency component with a reduced power loss. A pulse signal is transmitted to a load circuit through a transmission cable connected to a secondary winding of a transformer. First and second transistors are connected to a primary winding of the transformer. A voltage output from an external power source is input to the primary winding of the transformer when at least one of the first and second transistors is conductive so that a pulse voltage signal is input to the transformer. A booster power supply circuit is located between the external power source and a middle point of the primary winding of the transformer. The booster power supply circuit superimposes a boost voltage onto the voltage input to the primary winding of the transformer so that a high-frequency component of the pulse voltage signal input to the primary winding of the transformer is enhanced.

Abstract: A method of increasing the system stability of an electricity supply network including the steps of locating programmable frequency sensitive relays at load shedding points within the network. Each relay controls one or more loads and contains programmable disconnect and reconnect conditions. One or more of the loads are disconnected from the network upon a relay detecting the programmable disconnect conditions. Each relay reconnects the load to the network when it detects the programmable reconnect conditions. Each relay includes a device for detecting the network frequency, a micro-processor including memory and software and a switching mechanism to disconnect and reconnect one or more of the loads. Each relay is programmed from a centralized network stability manager which can designate programmable conditions for each relay. The communications between each relay and the stability manager can be via broadcast or sequential point-to-point communications.

Abstract: An AC attenuator system including a compensation circuit for providing a selectable trimming impedance for the AC attenuator. The compensation circuit comprises a plurality of capacitors preferably coupled in parallel with a portion of the attenuator, wherein the capacitors have binary weighted values. The compensation circuit also includes a plurality of switches, wherein each switch is coupled to an input of each of the plurality of capacitors and is further coupled to the AC attenuator circuit. The switches are preferably microelectronic machined system (MEMS) switches. The compensation circuit further includes a memory element coupled to the plurality of switches. The memory element stores a value, preferably a digital or binary value, which is operable to open/close selected switches.

Abstract: A capacitive switch is presented including an oscillator, with a gauge length and an evaluation circuit. The oscillator delivers a measurement signal and the gauge length has at least one sensor with a sending electrode and a measurement electrode. The switch has a low noise emission and is especially invulnerable to incident noise due to the fact that there is a noise source and two correlators. In the first correlator, frequency-spreading of the measurement signal takes place. The frequency-spreading measurement signal is connected to the second input of the second correlator and to the sending electrode. The measurement electrode is connected to the first input of the second correlator.

Abstract: A sensing circuit is useful with a power outlet and a power tool having power supplied thereto via the power outlet. The sensing circuit includes a generator, a transmitter, and a detector. A first signal having a high frequency is developed by the generator and supplied to a first terminal of the power outlet by the transmitter. The detector is coupled to the second terminal of the power outlet and tuned in accordance with the high frequency to develop a second signal indicative of whether the power tool is coupled to the power outlet. The sensing circuit may be used in conjunction with a regulating circuit and a two-position switch useful for controlling the electrical energy supplied to the power tool and a vacuum cleaner having the power outlet disposed thereon.

Abstract: The recreational vehicle jack remote control is for use with a recreational vehicle having a pair of support jacks which are raised and lowered by an electric motor connected to the jacks. The electric motor is controlled by a normally open, double-pole, triple throw switch in the recreational vehicle. The recreational vehicle jack remote control is a modification of the circuit which includes a portable radio frequency transmitter, at least one radio frequency receiver mounted in the recreational vehicle, and a plurality of relays. The transmitter has an "up" button for raising the support legs, and a "down" button for lowering the support legs. When the "up" button is pressed, the relay coil of at least one relay is energized, closing the relay switch contacts to apply current to the electric motor with the proper polarity for raising the legs.

Abstract: A miniaturized high frequency switching device is capable of giving an optimum over-all impedance over the length of a signal path while compensating for inevitable impedance variation seen in a particular segment of the signal path. The switching device includes a contact block having fixed contacts and a movable contact. The fixed contacts and the movable contact are surrounded by an electromagnetic shield which is supported on a conductor base to be grounded therethrough for isolating the current path from a surrounding electromagnetic field. The fixed contacts are formed respectively on one ends of terminal pins provided for electrical connection to an external load circuit operating on high frequency signals. The terminal pin extends through an insulation ring fitted in the conductor base so as to be electrically insulated therefrom and form the signal path flowing a high frequency current.

Abstract: A circuit arrangement (11) has an activating circuit (13) for a sensor element (12) of a touch contact switch, which in one embodiment of the invention contains a frequency generator (16). The frequency generator (16) generates a frequency-modulated activating signal (17), which is applied to the sensor element (12). In another embodiment the forming of the activating signal (17) takes place in a microcontroller (48), containing eventually the activating part (13) and or the evaluation of the signal. Through passing through a large frequency range for the activating signal (17), the influence of extraneous signals, even when using a lower signal voltage, is minimized.

Abstract: A multi-range power supply unit with an automatic switchover between ranges for different power supply voltages is disclosed for use with devices such as circuit breakers or contact systems. The power supply unit preferably has only two input connections for an input voltage range of approximately 20V-230V. Between the two input connections there is a rectifier circuit with a voltage stabilizing element, such as a Z-diode or equivalent device, connected in parallel. Connected in series to the rectifier circuit is a current divider. The current divider includes a capacitance and a thermistor. The thermistor preferably has a positive temperature coefficient (PTC). The power supply unit can be used for a power supply with DC voltage and for a power supply with AC voltage.

Abstract: A flexible capacitor is used in a switch circuit arrangement for activating a vehicle horn. The switch circuit arrangement includes an astable circuit having a flexible capacitor. The astable circuit generates a signal having a frequency that varies in response to force applied to the capacitor. A programmed frequency sensor activates a horn activation signal if the frequency of the signal falls below a programmed threshold.

Abstract: An isolated gate driver device for a power switching device having a plurality of transistors includes a primary circuit having a voltage source of a first voltage potential. The primary circuit constantly switches the voltage source to generate first and second load signals based on control signals received from a microcontroller. The first load signal is modulated at a first frequency for enabling the transistors, and the second load signal is modulated at a second frequency, different from the first frequency, for disabling the transistors. A plurality of high frequency transformers corresponding to each of the transistors is coupled to the primary circuit. The transformers have a primary side for receiving one of the first and second load signals and a secondary side for transforming the one of the first and second load signals into corresponding signals at a second voltage potential.

Abstract: A decoupling capacitor for an integrated circuit is operatively coupled to a supply and to control circuitry for isolating the capacitor. The control circuitry automatically isolates the capacitor in response to a current through the capacitor exceeding a certain threshold, but tends to restore the capacitor to operation if the current is merely caused by momentary conditions, rather than substantial failure of the capacitor. The control circuitry includes a first control device for automatically switching to an off state to isolate the capacitor in response to a voltage produced by the current exceeding a certain threshold. A discharging device tends to discharge the voltage and automatically turn on the first device when the current is caused by momentary conditions. The discharging device may include a control device responsive to an external control signal for switching the first control device on and off.

Abstract: A power source miswiring detection apparatus for detecting a miswiring of wires of a power source, including a pulse generator for generating a first pulse having a pulse width corresponding to a first phase difference between a first pair of two phases of a three-phase alternating power source, and a second pulse having a pulse width corresponding to a second phase difference between a second pair of two phases of the three-phase alternating power source which is different from the first pair of two phases, and a microcomputer for detecting a third phase difference between the first pulse and the second pulse to judge whether the third phase difference is in a predetermined range, and detecting the miswiring if the third phase difference is judged to be out of the predetermined range.

Abstract: A low voltage power inverter utilizes reed switches to control a number of display tubes. The reed switches are controlled by magnetic coils or permanent magnets. The magnetic coils receive a control signal from a control circuit. The control circuit is powered by a capacitor coupled around a power lead and a capacitor coupled around a return lead. The permanent magnet is coupled to a mechanical actuator.

Abstract: An electrical power transmitting system (50) in accordance with the invention includes an alternating current electrical power generator (12) for producing alternating current on an output having a specified maximum; at least one electrical load (22) which is coupled to a point of regulation (16) in the electrical transmitting system; a feeder (14) having a specified maximum voltage drop, a length extending between the output and the point of regulation for transmitting the alternating current to the point of regulation, an inductance having an inductive reactance at a fundamental frequency of the alternating current, a capacitance (54, 66, 80 and 100) in series with the inductance having a capacitive reactance at the fundamental of the frequency of the alternating current which cancels at least part of the inductive reactance at the fundamental frequency of the alternating current to provide a reduced impedance in the feeder at the fundamental frequency of the alternating current to produce a reduced voltage

Abstract: A method of and apparatus for actuating an automatic transfer switch for disconnecting a motor load from a normal source of voltage and reconnecting the load to an alternate source of voltage at a time when phase differences between the output voltage of the disconnected motor load and of the alternate source voltage are minimized to prevent excessive in-rush currents to the motor upon reconnection. Actuation of the transfer switch is commenced when the difference in phase between the normal source and alternate source is equal to a predetermined number of degrees depending upon whether the alternate source frequency is greater or less than the normal source frequency.

Abstract: A decoupling capacitor and protection circuit is provided that will assist the power supply network in stabilizing the voltage near circuits that demand short rapid transitions in electrical current. The protection circuit also significantly reduces the amount of electrical current drawn by defective large area decoupling capacitors. An inverter stage controls a switching circuit connected in series with a decoupling capacitor. A feedback circuit is provided from the output of the capacitor to the switching circuit. If the capacitor goes bad, then a voltage is present on the feedback circuit and the switching circuit ensures that the output of the failed capacitor is presented with an open circuit so that the short circuit current flow through the capacitor is eliminated. In this manner, the integrity of the other circuits located near the failed capacitor will operate appropriately.

Abstract: A high-voltage semiconductor driving circuit to be instantaneously operated for the duration of an arbitrary pulse width can be effectuated through an extremely simple circuit configuration.The circuit comprises a pulse transformer (2) which receives an input pulse signal and generates a pulse voltage, a diode (3) which conducts the pulse voltage to the capacitive gate electrode of the high-voltage semiconductor switching element (5), and another switching element (4) which is connected in parallel to the diode (3) and adapted to discharge, at the falling of the pulse voltage, the gate capacitance which has been charged at the rising of the pulse voltage.

Abstract: A method and apparatus for protecting a DC-AC converter having a transformer. According to one embodiment, an oscillator generates a periodic signal having a frequency. A switch switches an input voltage across a first winding of the transformer in accordance with the periodic signal. A watchdog device disables the switch if the frequency falls below a threshold frequency.

Abstract: A window glass in a motor vehicle body is slidable in a vertical direction within a window frame by means of an electric motor controlled by "up" and "down" switches. The window glass slides with reference to a window guide channel. The window guide channel incorporates a metal carrier or other electrical conductor which receives the output from electrical oscillating means. If a human hand, or other part of the human body, is present within the frame of the window, when the window is open, and within a predetermined distance from the window guide channel, the resultant capacitive effect will change the output of the oscillator. This output change is detected by a detecting unit and opens a switch. This switch is connected in series with the "up" switch for the window drive motor and thus either stops the motor, if it is driving the window glass upwards, or prevents the window glass from being so driven.

Abstract: In one aspect of the present invention, a contactless inductance switch is disclosed for use with a joystick. The switch is mechanically connected to a mass which is movable between a first and second position. When an operator presses the switch, the mass moves to the second position adjacent to an electrical circuitry. Sensing circuitry measures the change in inductance in the coil and produces a control signal indicating that the switch was pressed.

Abstract: An electronic switch circuit switches out bad decoupling capacitors on a high speed integrated circuit chip. The circuit comprises a control device that operates in the subthreshold or off device state to detect leakage in a decoupling capacitor. This control device operates in a low impedance state if the capacitor is good and in a high impedance sate if the capacitor is bad. A feedback circuit is connected from an internal node of the capacitor to a gate of the control device so that once a state of the capacitor is detected it can be stored on the gate of the control device. A single external signal source shared by a group of capacitors activates the control device to detect leakage in the capacitor. The circuit operates to switch out capacitors that fail during normal operation.

Abstract: A microprocessor based switch such as a circuit breaker generates digital rms representations of analog load currents from n samples of the analog currents per cycle synchronized to the line frequency, where n is an odd integer equal to a selected highest order harmonic to be detected plus 2. A routine determines whether the power system is 50 or 60 Hz, and automatically sets the sampling interval to provide exactly n samples per cycle for the connected source. Terminals for rapidly resetting an analog memory for calibration and field testing of a long delay trip are hidden behind a removable rating plug.

Abstract: The object of the present invention is to enable detecting operation states of numerous switches in a cordless coordinate reading system. The coordinate reading system body is provided with the switching circuit for selecting the excitation signal, so that one of the groups of sense lines can be excited with a plurality of frequencies. The coordinate indicator is provided with the resonant circuit and the groups of devices for setting frequency which modify the resonance frequency of the resonant circuit in accordance with the press of the switch, enable the resonant circuit to resonate with any one of a plurality of the resonance frequencies, and further slightly modify the resonance frequency. Further, the coordinate reading system body is provided with the circuit for detecting the phase contrast between the induced signal from the coordinate indicator and the excitation signal.

Abstract: A microwave proximity detector includes a microwave oscillator circuit having a dielectric resonator, or having a micro strip line as an inductor thereof so as to sense a change in an oscillation frequency or output from the oscillator circuit caused by a variation in an impedance of a circuit including the dielectric resonator, or of the micro strip line, due to a loss which takes place in a leakage magnetic field from the micro strip line when an object approaches the leakage magnetic field, thereby detecting an object in the neighborhood of the switch.

Abstract: A protection system (80) for a first generator unit (12) connectible by a first switch (24) to a power generating system having at least one additional generator unit with the at least one additional generator unit being connectible in parallel to the first generator unit with the first switch being opened in response to a first control signal to enable the first generator unit to be disconnected from the parallel connection to the at least one additional generator unit in accordance with the invention includes a signal generator (12) for generating a reference signal having a frequency proportional to a frequency of a voltage generated by the first generator unit; a sensor (14) for sensing a common frequency at a point of reference of voltage generated by the generator units of the power generating system; and a controller (14) responsive to the signal generator and the sensor, for calculating a difference between the frequency of the reference signal and the common frequency and for generating the first con

Abstract: A method for releasing the contacts of a sticking relay by sensing whether or not the relay contacts stick together in a closed condition and when the contacts stick together, applying an AC voltage on pulsating DC voltage to the winding of the relay coil. The mechanism for sensing the sticking relay contact condition is a comparator to compare the output load of the relay with the exciting control signal to energize the relay coil.

Abstract: A self contained sensor module mounted on a power transmission line. The module is capable of measuring various parameters such as line current, voltage, conductor temperature, and ambient temperature. The parameter values are processed by sensor electronics which digitize and transmit the values to a ground receiver. The sensor module normally derives its power through electromagnetic induction resulting from current flowing through the transmission line. The module contains a power back-up system, including a battery, which allows sensor operation with minimum current and zero current in the transmission line. The battery is float charged while the sensor is mounted on the transmission line using excess energy derived through electromagnetic induction. When line current drops to a predetermined minimum value, float charging is disabled and the battery supplies power to the sensor module.

Abstract: The invention relates to a change-over switch suitable for use in the case of connecting, e.g., a camera integrated type VTR to a television receiver. A first input terminal and an output terminal are closely arranged. The first input terminal, the output terminal, and switching means are connected by a parallel line consisting of first and second signal lines. The first input terminal and the output terminal are connected by the first switching operation. The second input terminal and the output terminal are connected by the second switching operation. Thus, the camera integrated type VTR, TV antenna, and TV receiver can be attached without complicatedly connecting the cables and without extending the cable from the antenna.

Abstract: Disclosed herein are individual sensor modules for mounting directly upon energized electrical power conductors and systems employing such modules, with principal emphasis upon the provision of both data transmitting and receiving means in each sensor module and at an associated ground station. The modules sense the instantaneous values of all parameters necessary to perform complete metering functions and, in one embodiment, are synchronized by a signal transmitted from the ground station and received by all modules so that the values are measured simultaneously on all conductors at a substation. The signals are transmitted by the modules in a time-synchronized manner and are in a condition for use directly by the ground station microprocessor. In another embodiment, data transmissions by a plurality of modules is synchronized to avoid data collisions by self-contained means within each module, requiring no synchronizing signal from the ground station.

Abstract: A power status monitor for an electronic system includes a charge/discharge model of the system power supply. The charge/discharge model contains an estimate of the amount of time during which energy-storage devices in a system DC power supply are capable of maintaining system operation following loss of AC power. The power status monitor monitors the frequency and an amplitude of the voltage of the AC power source for signs indicating imminent failure of the AC power source. In the event that such signs are detected, the estimate in the charge/discharge model is decremented at a rate corresponding to the rate at which charge is consumed. A trip value, applied to the charge/discharge model, determines the time at which a signal is generated enabling an orderly shutdown of the system load. If acceptable AC power is resumed before the trip value is reached, the charge/discharge model increases its estimate of the time available at a rate corresponding to the charge accumulation in the DC power supply.

Abstract: Detectors (11a-d) are located at a plurality of locations and include go, no-go decision processor apparatus for subjecting outputs of the detectors (11a-d) to a go, no-go decision process. First signal generator and transmitter apparatus (12a-d) are interconnected to said go, no-go decision processor apparatus for generating and transmitting signals responsive to the output of said go, no-go decision processor apparatus, the signals being transmitted in a wave form configured to maximize differentiation from noise and interference. First data receiver apparatus (13) receives the signals from said first signal generator and transmitter apparatus (12a-d) and includes wave form recognition apparatus. A reprogrammable central processor apparatus (14) is interconnected to the data receiver apparatus (13) for providing action outputs representative of one or more actions to be taken in response to one or more signals received from the first data receiver apparatus (13).

Abstract: A power train of an uninterruptible power supply selectively transforms its load from a primary source of power to a reserve source of power under control of a stored program control operating in real time. A microprocessor operating in conjunction with a prioritized interrupt controller and a plurality of external counters monitors and responds to signal conditions existing at various points of the power supply. In particular, the amplitude of a primary AC voltage source is sampled at precise angles of the sinusoidal waveform in response to a comb pulse waveform generated to conform to the actual period of the primary AC voltage. The frequencies range is determined by comparing a count interval to the period of the primary AC voltage. Relative power flow from the primary AC voltage source and a reserve AC voltage signal is controlled by relative phasing of the two signals.