Abstract: Methods of controlling lockout of a switching or isolating component of an electrical grid are provided. A method of controlling lockout of a switching or isolating component includes, responsive to a plurality of trips occurring at the switching or isolating component during a predetermined time window, incrementing, by the switching or isolating component, a plurality of counters, respectively, and determining whether a number of the trips meets or exceeds a predetermined threshold. Moreover, the method includes, responsive to meeting or exceeding the predetermined threshold, driving the switching or isolating component to lockout. Related switching or isolating components are also provided.

Abstract: A motor protector and a method for operating the same.

Abstract: A secondary-battery protection circuit is configured to, in response to detecting that a first switching circuit is turned on and a second switching circuit is turned on, supply a first output voltage to a first load between a first terminal and a second terminal; and supply a third output voltage to a second load between the first terminal and a third terminal, the third output voltage indicating the sum of the first output voltage and a second output voltage, the second output voltage corresponding to a voltage across a second secondary battery. In response to detecting that the first switching circuit is turned off and the second switching circuit is turned on, the secondary-battery protection circuit is configured to stop supplying the first output voltage to the first load; and stop supplying the third output voltage via the first terminal and the third terminal.

Abstract: The invention relates to an electrical power distribution apparatus (100) connectible to one or more loads (119). The electrical power distribution apparatus (100) comprises inter alia one or more taps (112) for supplying the loads (119) with electrical power. On top of circuit breakers (108) to switch off the power supply in order to protect the loads against damage, there is also arranged a second layer of soft fuse switches (110) which are arranged to switch on or off the power supply at the taps (112) to control distribution of the power. The soft fuses (110) operate in dependence on and in response to commands issued from a controller (105) which in turn operates and issues those commands in response to and independence on the voltages and amperages monitored at those taps (112) by way of a monitoring module (111). Switching on/off occurs at amperage and voltages lower than the critical threshold values to which the circuit breakers (108) respond to.

Abstract: An impedance matching device including a transformer having an input side and an output side, wherein the input side includes a first coil having a first impedance, a second coil having a second impedance, and a third coil having a third impedance. An input power connector is electrically connected to the input side of the transformer, and a pass through output power connector is electrically connected to the input side of the transformer, and the pass through output connector also is electrically connected in parallel to the input power connector. A speaker output connector having four electrical contacts is included, wherein a first pair of the four electrical contacts is connected electrically to the first coil, and a second pair of the four electrical contacts is connected electrically to the second coil.

Abstract: Power distribution systems and methods are described. In one example, a method of determining by a first circuit protection device in a zone selective interlocking (ZSI) system whether to output a blocking signal to a second circuit protection device in the ZSI system is described. The method includes detecting, by a current rate of change sensor, a rate of change of a current flowing through the first circuit protection device. A trip unit receives a current rate of change signal from the current rate of change sensor. The current rate of change signal is proportional to the detected rate of change of the current flowing through the first circuit protection device. The trip unit determines whether to output the blocking signal to the second circuit protection device based, at least in part, on the current rate of change signal.

Abstract: A stacked heat dissipating module of an electronic device has a holding frame, and at least one first heat conducting medium layer, a heat dissipating medium layer, a first heat sink layer, at least one second heat conducting medium layer and at least one second heat sink layer stacked with each other. The at least one first heat conducting medium layer is mounted on at least one heating component of the electronic device to dissipate heat generated from the at least one heating component. Moreover, the holding frame, the heat conducting medium layers and the heat sink layers have corresponding housing holes for exposing an exposed component of the electronic device to bring the exposed component's function into full play.

Abstract: A system for protecting a load from a fault on a line comprising: a detection circuit monitoring the line; and a switch interposed between the line and the load; wherein the detection circuit triggers the switch to disconnect the load from the line when the fault is detected. The detection circuit may trigger the switch within one second of detecting the fault. The detection circuit may monitor the line voltage of the line and the fault may be detected when the line voltage exceeds 125% or 130% of the normal voltage. The load may be automatically reconnected to the line when the line voltage drops to within 5% or 10% of a normal voltage. The fault may be any one or more of an open-neutral, an over-voltage, an under-voltage, a phase loss, and an external trigger, such as an access sensor, a smoke sensor, and/or a heat sensor.

Abstract: A power conversion apparatus includes: a line breaker that is connected in series to a direct-current power supply; a first capacitor that is connected in parallel to the direct-current power supply through the line breaker; a discharge circuit that includes a resistor and a first switching circuit connected in series and is connected in parallel to the first capacitor; a power converter for driving a synchronous machine; a second capacitor that is connected in parallel to a direct-current side of the power converter; a second switching circuit that is connected in series between the first capacitor and the second capacitor; and a control circuit for controlling the discharge circuit. The control circuit controls the discharge circuit on the basis of the voltage of the first capacitor and the voltage of the second capacitor.

Abstract: An alarm device includes a first detecting unit and a controlling unit. The first detecting unit has an isolating circuit, a first enabling circuit, a second enabling circuit and an output circuit. The isolating circuit generates an adjusting signal according to an input signal. The first enabling circuit generates a first enabling signal according to the adjusting signal. The second enabling circuit generates a second enabling signal according to the first enabling signal. The output circuit outputs a first detecting signal according to the second enabling signal. The controlling unit outputs a control signal according to the first detecting signal. The control signal controls an electronic device to operate under a standby mode when the first detecting signal refers to an abnormal status.

Abstract: Disclosed herein is a Fourier transform-based phasor estimation method and apparatus capable of eliminating the influence of exponentially decaying DC offsets. According to a Fourier transform-based phasor estimation method according to an embodiment of the present invention, an input signal is sampled, and samples of one-cycle data of the input signal are separated into at least two sample groups. A Discrete Fourier Transform (DFT) is performed on each of the sample groups. A DC offset included in the input signal is calculated on a basis of results of the DFT on each of the sample groups, and an error caused by the DC offset is calculated using the calculated DC offset. A phasor of a fundamental frequency component included in the input signal is estimated by eliminating the calculated error, caused by the DC offset, from the results of the DFT on the input signal.

Abstract: A short circuit protection circuit which readily recovers a relay drive circuit to an output operation state after a short circuit is cancelled while preventing the relay drive circuit from being damaged by a short circuit. The relay drive circuit outputs a drive current to a load in accordance with a first control signal. A short circuit detection circuit detects the occurrence of a short circuit at an output side of the relay drive circuit and suspends output operation of the relay drive circuit when a short circuit occurs. Further, the short circuit detection circuit intermittently transmits a recovery signal to the relay drive circuit in a certain time interval after a predetermined time elapses from when the short circuit occurs to recover the output operation of the relay drive circuit. The time interval is gradually increased whenever the recovery signal is transmitted.

Abstract: Electrical distribution systems implementing micro-electromechanical system based switching devices. Exemplary embodiments include a method in an electrical distribution system, the method including determining if there is a fault condition in a branch of the electrical distribution system, the branch having a plurality of micro electromechanical system (MEMS) switches, re-closing a MEMS switch of the plurality of MEMS switches, which is furthest upstream in the branch and determining if the fault condition is still present. Exemplary embodiments include an electrical distribution system, including an input port for receiving a source of power, a main distribution bus electrically coupled to the input port, a service disconnect MEMS switch disposed between and coupled to the input port and the main distribution bus and a plurality of electrical distribution branches electrically coupled to the main distribution bus.

Abstract: A fault interrupter and a method of operating a fault interrupter to reduce arcing time during fault interruption. Fault interrupter operation is delayed following detecting a peak current such that its operation occurs at a point of the current wave resulting in reduced arcing during fault isolation.

Abstract: An electronic trip unit for a circuit breaker is disclosed. The electronic trip unit has a processing circuit, and a real time clock circuit that is operational in the absence of current in the circuit breaker. The processing circuit is responsive to input signals representative of a current in the circuit breaker, and the real time clock circuit is in signal communication with the processing circuit. In response to an off event at the circuit breaker following a current flow condition thereat, the real time clock circuit is configured to generate time information relating to the circuit breaker being off as a result of the off event for use by the processing circuit.

Abstract: A method for providing an analog or digital circuit that senses both low and high input voltage and operates to disconnect both line and neutral electrical power connections to a protected device when abnormally low or high voltages are received from a single- or multi-phase power source, and reconnects the protected device when input power has stabilized. The sensing circuit and power supply is functional with voltages up to at least 240 Vac. The nominal 120 Vac circuit is designed to withstand a 6 kilovolt surge without damage. The method does not disconnect the ground line during an out-of-tolerance voltage condition.

Abstract: A linear power controller system may be implemented that includes locked-rotor protection circuitry that is primarily assembled using analog circuit components. The locked rotor protection circuitry may be part of a power module in the system. The power module may be a switched power source that includes temperature circuit. A control loop may be established in the system to maintain the voltage across a motor that is driver by the power module. Circuitry for establishing a close loop with a motor may be positioned in a control head in the system or in a power module in the system. Temperature protection circuitry may be integrated into a current source in the power module to provide automatic thermal shutdown of the current source. The linear power module may specifically include analog circuitry that is arranged to establish a control loop with the motor.

Abstract: Methods and apparatuses for fault condition protection of a switched mode power supply. In one aspect of the invention, a power supply circuit having an auto-restart function to turn the power supply on and off repeatedly under fault conditions is included. In one embodiment, one or more off-times following detection of a fault condition is smaller than subsequent off-times.

Abstract: The present invention is directed towards a discrete protection circuit located on a circuit card, and systems and methods related thereto. The protection circuit protects circuit card components from an inrush current and overcurrent conditions. The discrete protection circuit includes a switch to control a delivered load current to an output port, an SCR which latches when an overcurrent condition is detected across a sense resistor, and a series of resistors and a capacitor that determines the retry delay subsequent to an overcurrent detection. Advantages of the discrete protection circuit of the invention over prior art integrated circuits include: lower parts counts, lower production costs, greater flexibility, and increased reliability.

Abstract: A resettable short-circuit protection circuit can terminate excessive fault currents automatically and quickly. The short-circuit protection circuit is switchable and has a low input impedance during normal operation so that there is not a significant voltage drop across the switching elements of the protection circuit. The short-circuit protection circuit allows a power source internal to a portable device to be safely connected to an external accessory where there exists the possibility that the connection could be shorted at the time power is first supplied to the external accessory or a short develops afterwards. After terminating a short-circuit condition, the protection circuit may be reset by cycling an enable signal. The fault termination and reset timing may be configured by selection of internal resistance and capacitance values.

Abstract: A plurality of preprogrammed switches is disposed in a looped distribution line downstream from a source of power to respond to a short circuit and to reconfigure the line to isolate the short circuit. Some of the preprogrammed switches are each provided with a unique open time interval, such as t1, t2 and t3. Others of the plurality of preprogrammed switches can then determine which switch is opening in response to the short circuit and can identify the portion of the line that is shorted. Certain of the preprogrammed switches can then reconfigure to protect the identified portion of the line.

Abstract: A portable device (1) with at least one optical output device (2) for displaying at least process data of a machine, a robot or a technical process, with at least one input device (3) for at least intervening in the operating functions of the device (1) and/or for operating the machine or robot or technical process, and having a safety switch device (12) for preventing the output of undesirable, unintended control commands for the machine, robot or technical process. The output devices (2) and input devices (3) are connected to a control device (14), which is accommodated in a housing (7) that is unbreakable as far as possible and at least one communication interface (17) is provided to an external control device disposed at a distance away. Several of the input and output devices (2, 3) are functionally combined by means of a touch-sensitive screen (4) in the form of a touch-screen (5) and the touch-sensitive screen (4) extends across substantial regions of the surface of the housing (7).

Abstract: An electronic trip unit for a circuit breaker is disclosed. The electronic trip unit has a processing circuit, a real time clock chip, and a power source for powering the real time clock chip in the absence of current in the circuit breaker. The processing circuit is responsive to input signals representative of a current in the circuit breaker, and productive of a trip signal for tripping the circuit breaker. The real time clock chip is in signal communication with the processing circuit. In response to an off event at the circuit breaker following a current flow condition thereat, the real time clock chip is configured to generate time information for use by the processing circuit, which is configured to apply the time information to calculate a cooling effect arising from the circuit breaker being off, thereby providing for thermal memory.

Abstract: It is constructed so as to detect a joint movement position of a robot arm by a position detector and a joint movement speed is calculated from change amounts of the joint movement position and elapsed time and is compared with an allowable movement speed and unlocking and locking of a brake are controlled so that the joint movement speed of an arm at the time of brake unlocking becomes within a constant value even when a shape, an attitude and a load condition of the robot arm vary. Therefore, movement work of the arm by the brake unlocking can be performed alone and a robot with high safety can be obtained.

Abstract: A recloser trips on one phase for single-phase only fault conditions, or all phases for multi-phase fault conditions. During power delivery, the recloser monitors the three phases of a power line (e.g., phases A, B, and C). If a fault is detected on one phase, then a timer is started and subsequently decremented. If the timer finishes counting down while the fault is still present, then it is determined if any of the other two phases are timing a fault. If so, then all three phases are tripped; otherwise, only the faulted phase is tripped.

Abstract: A recloser trips on one phase for single-phase only fault conditions, two phases for two-phase fault conditions, or all three phases for three-phase fault conditions. During power delivery, the recloser monitors the three phases of a power line (e.g., phases A, B, and C). If a fault is detected on one phase, then a timer is started and subsequently decremented. If the timer finishes counting down while the fault is still present, then it is determined if any of the other two phases are timing a fault. If so, then those phases having a fault are tripped. Thus, only the faulted phase(s) is (are) tripped.

Abstract: A power line flicker protection circuit, used to protect electronic equipment, features the following: A transformer (T1), provides power to the DC power supply (FIG. 2), and signaling to the auto reset watchdog circuit (FIG. 3) and the timer circuit (FIG. 4). The auto reset watchdog circuit monitors the AC signal, and upon interruption or flicker, sends a reset signal to the timer circuit. The timer circuit controls a control relay (S1), which in turn controls the 120 Vac power to the load. When the reset signal is received, the AC power to the load is removed, protecting the load. After a set time interval, after the AC power is back to normal, the AC power is automatically reconnected to the load.

Abstract: A method for handling the voltage drop, at least in the control unit of a robot with a PC control is provided that minimizes the time of a plant stoppage and avoids wasteful process interruptions. The PC control has a real time operating system for the time critical control and regulation of the robot movement and a standard PC operating system for communication with an operator. In the case of a voltage drop a battery/accumulator operation takes place with running robot movement and optionally application operations broken off or ended in a clearly defined manner. Then, working processes of the control are terminated. The contents of the working memory at the termination time concerning the real time operating system and robot control programs are stored, particularly as an image, in at least one mass memory. For restarting the robot after such a stoppage thereof the standard PC operating system is loaded in the conventional manner into the working memory and started.

Abstract: A hydraulic time delay device couples to a fault-sensing element in a circuit recloser. The time delay device includes a piston that has an external connection and is operable to move through a housing in the device to cause hydraulic fluid in the housing to flow out of the housing and into a passageway. The time delay of the time delay device corresponds to a time required to move the piston. A first adjustable orifice is formed the passageway to define an adjustable first fluid flow path through the passageway. An adjustable valve is positioned to provide an adjustable second fluid flow path through the passageway. A second adjustable orifice is formed in the passageway to provide further adjustment of the second fluid flow path. Adjustment of the first orifice, the valve, and the second orifice affect the time required to move the piston.

Abstract: A UPS device of universal application provides a pair of backfeed relays, which are mandated by certain countries outside the United States, controlled by an overall control circuit to perform in conjunction with the connection of neutral to system ground to avoid damage to a load, UPS and power utility. The control circuit is responsive to an anomaly in the power supply of a power utility to enter a backup mode wherein power is supplied by a battery power supply through an inverter to the load. Entry into backup mode occurs with a delay-based switching logic which governs the control circuit's operation of the backfeed relays and formation of the neutral to system ground connection.

Abstract: A fault protection arrangement for electric power distribution systems includes a plurality of power sources connected to a distribution bus through circuit breakers and a plurality of loads connected through switches to the distribution bus, along with fault sensors in each of the power source lines and load lines and a control means responsive to detection of a fault in a load line to open the circuit breakers in the power source lines connected to the distribution bus and then to open the switch in the load line containing the fault and then to reclose the circuit breakers in the power source line to resume power flow to unaffected loads. The embodiments provide automatic fault isolation and automatic system realignments using a minimum amount of circuit interrupting devices in conjunction with a distributed control system. The embodiments eliminate fault coordination difficulties and improve power continuity as compared to conventional hierarchal protective schemes.

Abstract: A monolithic electronic circuit breaker having an input terminal, an output terminal, and a controllable impedance connected between the input and output terminals. A current sensor generates a current magnitude signal indicative of the current flowing between the input and output terminals. In one embodiment, an over-current circuit generates an over-current signal when the current magnitude signal exceeds a threshold. In response to at least a first occurrence of the over-current signal, a control circuit controls the controllable impedance so as to reduce current through the controllable impedance for a period of time, and then automatically increase current through the controllable impedance. Further, in response to an N.sup.th (N>1) occurrence of the over-current signal, the control circuit controls the controllable impedance so as to reduce current through the controllable impedance and does not thereafter automatically increase current through the controllable impedance.

Abstract: The present invention provides a system and method for integrated reclosing of circuit breakers in a power substation by providing a programmable controller which is programmed to detect the opening of a circuit breaker and initiate a reclosing window during which time it can generate a command signal to the opened circuit breaker commanding it to close.

Abstract: The instant invention is a protection device for electrical equipment operating on a single or three phase alternating current power supplies. The device consists of an electrical circuit having at least one relay which is energized by at least one leg of an incoming power supply. The relay is energized by either a manual toggle or an automatic timer when the power supply is fully operational. Thus, upon placement of the device into an electrical line, power restoration after a power interruption is made possible only by manual initiation of the toggle or by an adjustable timer that counts down a preset period of time before initiation.

Abstract: A reset circuit for an overload relay includes a timing circuit coupled to a switching circuit for automatically resetting the relay a predetermined time after a trip. The timing circuit includes a capacitor and a resistor in parallel with a reset coil. The capacitor is charged during normal operation and begins to discharge through the resistor following a trip at a first rate determined by the size of the resistor. The switching circuit includes a pair of transistors, a pair of capacitors and a pair of resistors. When the capacitor in the timing circuit has discharged a predetermined amount following a trip, the switching circuit is triggered and couples the capacitor to ground through one of the transistors, causing a rush of current through the reset coil sufficient to reset the relay.

Abstract: A power semiconductor component assembly includes a power semiconductor component having a semiconductor body. A controllable switch is connected to the power semiconductor component. A temperature sensor has a given reset time. The temperature sensor is connected to the controllable switch for turning on the controllable switch to control the power semiconductor component from a conducting state into a range of higher resistance once a temperature in the semiconductor body of the power semiconductor component attains a critical value. A delay member is connected between the temperature sensor and the controllable switch. The delay member is triggered upon response of the temperature sensor and has a delay time being longer than the given reset time, for preventing blocking of the controllable switch during the delay time.

Abstract: A first series circuit of a current detector and a first switch is connected in series with a battery, and a second series circuit of a resistor and a second switch is connected in parallel with the first series circuit. A control device controls an on and off state of the first and second switches to provide over-current protection of the battery. In particular, the control device turns off the first switch to cut-off battery over-current and turns on the second switch when the battery current exceeds a specified level as detected by the current detector. Then, after the battery current, which flows through the second series current, drops below the specified level, the first switch is returned to an on state to again allow battery discharge.

Abstract: A fault detection circuit monitors voltage drops associated with phase windings of a brushed or brushless reversible multi-phase motor and compares them with reference voltages to determine if the motor is out of normal operating range parameters and if a valid fault condition exists. The fault detection circuit-is included in a motor control circuit and is configurable for use with a wide variety of motors having a broad range of load characteristics. The fault detection circuit includes a programmable clock generator which generates time delays for masking faults detected during start-up and during motor phase sequencing. The fault detection circuit thereby avoids transient and spurious faults and prevents the unnecessary termination of motor operation. The length of the mask time delay required for effective fault detection operation depends on the load characteristics of the selected motor.

Abstract: Circuit for protection of an amplifier stage comprising circuit switching means for turn-off of the stage and piloted through a logic gate OR by a monostable, which generates upon arise of abnormal operating conditions turn-off command signals having a predetermined duration.A sensing circuit upon persistence of abnormal conditions at start-up or during normal operation also sends turn-off signals through the logic gate OR after enablement through a gate AND.The signals of any enablement at the logic gate AND arrive through a logic gate OR from a window comparator coupled with stage start-up members, from the monostable, and from the output of said logic gate AND as a confirmation signal.

Abstract: A digital voltage protection circuit (138) and a phase monitor circuit (154, 160, 162, 168) disconnect AC-powered user equipment (22,182) from the AC power supply (141) whenever the AC power line voltage is outside a predetermined operating voltage window and when any two phases of the power supply (141) are separated by more than a predetermined phase angle. The user equipment (182) is automatically reconnected to the power supply (141) only after the power line voltage and phase remain continuously within operating range for a predetermined delay period. The voltage monitor (138) contains a digital comparator (18) that uses integrated circuit digital logic thresholds as reference voltages for setting upper and lower voltage window limits. The controller protects the user equipment from both over-voltage and under-voltage (brownout) conditions and from phase errors.

Abstract: An electronically controlled recloser for an electrical power distribution system is powered by at least one current transformer coupled to give an output in response to power line current. A voltage is stored on a large and a small capacitor in response to the line current and is compared with a reference voltage for determining the level of line current. When abnormally high levels of current appear on the line, it is opened for a short period of time. The energy stored on the capacitors is supplied to power the recloser during low line current conditions. At an end of a given time period following the opening of said line, the recloser recloses the line. If the abnormal condition persists, the recloser again opens and closes the line. When there is a surge of line current, the large capacitor is effectively removed from the circuit so that a response will not be delayed while the large capacitor charges; therefore, the charge on the small capacitor provide a quick start for immediate response.

Abstract: A circuit is provided which responds to single or multiphase low or lost voltage situations and in the case of multiphase systems to phase reversals or shifts to disconnect a single or multiphase load from its source. A timing circuit is provided which prevents reactivation of the load until a prescribed time interval has elapsed. The reactivation may be either automatic or manual.

Abstract: A circuit for protecting electronic equipment such as computers, laser printers, fax machines, and the like from damage due to electrical transients associated with a temporary power interruption is connectable between a source of A.C. power and the electronic equipment. The circuit disconnects the equipment from the power source during a temporary power outage and maintains the equipment disconnected from the A.C. power until transients in the line voltage have abated. The circuit reconnects the equipment to the A.C. power source after a preselected time delay from the initial power interruption. The circuit keeps track of time during a power interruption without the use of batteries.

Abstract: A line voltage monitor and controller disconnects AC-powered user equipment from an AC power line whenever the AC power line voltage is outside a predetermined operating voltage window. The equipment is automatically reconnected to the power line only after the power line voltage remains continuously within the operating voltage window for a predetermined delay period. The controller protects the user equipment from both over-voltage and under-voltage (brownout) conditions.

Abstract: A microcomputer based reclosing relay performs a number of sequences to generate a succession of reclosure signals for a circuit breaker at timed intervals. The digital processing unit of the relay maintains flags, counts and running times for generating the succession of timed reclosures in a volatile memory. Periodically, these flags, counts and running times are copied to a non-volatile memory such as an EEPROM. Upon restoration of power following an interruption of power which results in loss of the contents of the volatile memory, the digital processing unit recopies the flags, counts and running times saved in the non-volatile memory back into the volatile memory, so that the relay can resume generating the succession of reclosures from the point at which power was lost. The flags and counts are copied to the EEPROM only when they change state, while the running times are only saved once a second to prolong the service life of the EEPROM.

Abstract: A protective time delay delay circuit delays energization to an electric load until a predetermined time has elapsed from a previous deenergization. A transistor has its emitter connected to an ac conductor and has its base coupled to an RC timing circuit. The collector is connected to the gate of a triac whose current electrodes are coupled to the thermostat conductor and to a load device. A small resistor and a zener can be connected to the transistor to provide brownout protection. A temperature sensitive resistor can be included to increase or decrease the lockout period as a function of temperature. This resistor can be remotely mounted in thermal proximity to the load to be protected. A thermistor placed in parallel to latching capacitor can provide thermal overload protection.

Abstract: An overload protection circuit for power supplies and telecommunications apparatus such as multifrequency ringing generators causes the output voltage to become zero when a current overload is detected. The voltage is kept at zero for a predetermined period of time. Then the output voltage is restored. If an overload is still detected, the output voltage is again brought to zero.

Abstract: A distribution line switchgear control which is particularly suitable for use with recloser switchgear which requires small amounts of power from the control for operation. The control is most usefully powered for continued operation by small amounts of line current provided through a power source current transformer and includes multiple capacitors which are arranged in a cascaded control power supply having a plurality of isolated stages. The line current is precisely monitored through sensing current transformers by the control which causes the recloser to trip, reclose and lockout, as is appropriate to protect the distribution line and distribution electricity. Inhibit circuits prevent the control from issuing a trip signal, unless sufficient energy exists in a trip portion of the cascaded power supply. A variety of volatile timers and counters enable the control to cause the recloser to trip, reclose and lockout.

Abstract: An auto-recloser for a power line has a high voltage closing coil (12) for closing the main contact (14) in the power line, the closing coil being energized via a non-latching switching (18) in turn controlled by a low voltage closing coil (20). A time closing pulse is applied to the low voltage coil (20) to close switch (18) for a very short time period. A coil protection (24) monitors the status of the main contants (14) and if these have not closed after a preselected time period of typically 100 ms then the protection circuit opens a normally closed switch in series with the low voltage coil (20) to prevent further closing pulses being applied in further attempts to close the main contacts (14).

Abstract: An overload protection circuit for a disableable amplifier includes a sensing resistor connected to provide indication of the current supplied to the amplifier and includes logic circuitry for producing a disabling control signal for a selected time interval following detection of the overload condition of the amplifier.