Showing papers on "Relay published in 1978"

Ultra High Speed Relay for EHV/UHV Transmission Lines -- Development, Design and Application

Abstract: A new protective relay that solves many of the problems associated with the protection of EHV and future UHV systems is described. Based on a traveling wave approach the relay system operates at ultra high speed and can detect and determine the direction to a fault in a few milliseconds. The relay operating principle, design and application are presented as well as results from computer simulation studies and laboratory tests. The first relay system was installed in the USA in Bonneville Power Administration's 500 kV system and represents a substantial contribution to present efforts to shorten fault clearing times as a method to improve system stability and power transfer capability.

Protective relay device

Abstract: An electrical device for protecting an alternating current network in which a static inverse time-overcurrent relay obtains network current information and relay circuit operating power from a current transformer having two secondary windings. Low transformer burden and accurate network information signals that are linearly responsive to a wide range of network current magnitudes are achieved through the use of a switching circuit that prevents the simultaneous operation of both secondary windings. The relay circuit employs an RC network with a short, precision time constant for curve shaping and employs digital counting techniques to provide time delay multiplication, precision time scale selection and a variable delay time variable in accordance with the magnitude of system current.

Ultra High Speed Relay for EHV/UHV Transmission Lines -- Installation-Staged Fault Tests and Operational Experience

Abstract: A new protective relay that solves many of the problems associated with the protection of EHV systems has been developed by ASEA, Sweden. Based on a traveling wave approach the relay system operates at ultra-high speed and can detect and determine the direction to a fault within a few milliseconds. The first relay system was installed in Wonneville Power Administration's (BPA) 500 kV system in April 1976. It represents a substantial contribution to BPA's present effort to shorten fault clearance times. The relay's setting procedure is described. The outcome of staged fault tests and one year's operational experience is presented and has confirmed the validity of the relay concept showing an ultra-high speed performance consistent with earlier laboratory results, with operating times of two to six milliseconds.

Integral relay low voltage retentive means

Abstract: An electromagnetic relay is provided with a high current "boost" coil, a lower current normal operating or "seal" coil and a static, electronic circuit that functions under low voltage conditions to energize the boost coil to retain the relay closed. An additional function of this static, electronic circuit is to energize the boost coil for a time interval on initial power application in order to assist in closing the relay, and this time interval automatically varies in the correct direction with variation in the supply voltage available to the coil so that the lower such available voltage is from its normal value, the longer the boosting time interval. At other times, both coils are energized in series at low current to hold the relay closed. This static, electronic circuit is small enough to be integrally incorporated within the housing of a conventional sealed power relay.

Telephone line monitoring circuit and method

Abstract: A novel circuit and method are described for monitoring a telephone line of a switched telephone system. The line monitoring circuit is interposed in the telephone system between the local subscriber-line from the central office and the on-premise continuation of that line at the subscriber's location. The line monitoring circuit has component circuitry for sensing both line-to-ground faults and extraneous AC voltages of a predetermined magnitude and frequency. Upon sensing a line-to-ground fault or an extraneous AC voltage of the predetermined magnitude and frequency, a control signal is transmitted to a relay control element which operates to disconnect the on-premise portion of the line from the portion of the line which extends from the subscriber's premise to the central office of the utility company. Visual indicators are also provided with the circuit. The indicators show whether a line-to-ground fault or an extraneous AC voltage fault has caused the relay to operate. The line monitoring circuit also provides a closed loop impedance path which may be used to test the impedance of the central-office line after the line monitoring circuit has operated to disconnect the central-office portion of the system from the on-premise portion.

Circuit arrangements for the control of a bistable relay

Abstract: Circuit arrangements for the control of a bistable relay having a capacitor connected in series with the relay coil. The series connection of the coil and the capacitor is connected to an excitation voltage for actuating the relay and simultaneous charging of the capacitor. When the excitation voltage is removed, the series connection is short-circuited through a semiconductor switch, whereby the capacitor is discharged and the relay switched back to its initial position. The bistable relay is thus operated as monostable relay.

Ground distance relay employing phase comparator measurement

Abstract: A ground distance relay employing phase angle comparator measurement is provided with additional input signals. In one embodiment, a two input ground distance relay is provided with two additional input signals. In this embodiment, the first two input signals comprise an OPERATE SIGNAL of the form IZ-V and a POLARIZING SIGNAL of quadrature shifted form. The third input signal comprises a #2 POLARIZING SIGNAL which is related to the zero sequence voltage at the relay. The fourth input signal comprises a CURRENT SUPERVISION SIGNAL which is related to the zero sequence current at the relay. These four input signals are directed to coincidence and timer circuitry. The presence of these four inputs provides improved relay security against undesirable relay operation for several existing problems. For example, additional security is provided for situations in which a single line to ground fault occurs at or just beyond the relay balance point where fault resistance may cause undesirable relay operation. Also, additional security is provided for situations in which double line to ground faults occur. Other embodiments are disclosed.

Data, text, or speech communications terminal - can carry out all possible communications functions over telephone lines, or by radio

Abstract: The terminal serves for signal transmission between individual mobile and fixed subscribers. The sation as a handset,or suitably connected units, comprising an earphone, a microphone, a keyboard for alphanumerical transmission of data or text signals; an electronic dialling system for long distance connection build-up; a tape matrix printer, possibly in parallel with a matrix running symbol display; an integrated transceiver unit, and a circuit with filter, amplifier and switching functions. A microcomputer unit for logic combination of processes is provided, so that signals can be exchanged as required over the telephone lines, data or teleprinter network. Calls can be answered, and a radio-telephone can be used. The terminal can be used for staff location and remote control, including its operation as an automatic radio-telephone interface and relay converter. Acoustic coupling to existing telephone and radio systems and to optical communications are possible.

Fuel security device

Abstract: A security device for a fuel such as natural gas having a series circuit of a relay switch, a hazard detecting switch, a relay switch operating coil and a timer. A valve coil is adapted to open and close a main fuel supply valve. The valve coil is connected in parallel to the series circuit. A reset switch is adapted to excite the valve coil and is connected in parallel with the relay switch. In one embodiment, the hazard detecting switch, the relay switch operating coil and the valve coil are coupled through a transformer in series with an electric source. The hazard detecting switch the relay switch operating coil and the valve coil are disposed on a secondary side of the transformer. The main fuel supply valve is normally closed such that in case of a power failure, the valve will close and remain closed.

Solid state relay having U-shaped conductive heat sink frame

Abstract: A novel solid state relay package has a U-shaped metallic frame which defines three surfaces of the general rectangular relay package. The open end of the U receives a circuit board containing most of the relay components. The interior of the frame is then filled with a solid plastic insulation material and terminal pins extending from the terminal board pass through the bottom of the solid plastic material to be accessible for external contact. The top of the housing receives a second terminal assembly for receiving power terminals connected to the main relay switching device and an LED indicator which is visible through the conductive U-shaped frame to indicate whether the relay is open or closed.

Protective control for vehicle starter and electrical systems

Abstract: A protective control for the starter and electrical systems of a motor vehicle, including a main relay for controlling the electrical system, and a starter relay for controlling the starter system. Electronic logic is provided for the electrical system which: (1) prevents energization of the main relay if the battery polarity is reversed; (2) if the battery polarity is correct, turns on the main relay when a master switch is closed; and (3) maintains the main relay in an ON condition when an AC signal from the alternator is sensed even if the masterswitch is subsequently opened. The latter prevents disconnection of the battery from the electrical system while the engine is running. Electronic logic is also provided for the starter relay which: (1) after the main relay is closed, turns on the starter relay when a starter switch is closed, to thus permit cranking of the engine; (2) automatically deenergizes the starter relay when the AC signal from the alternator attains a designated threshold frequency, which corresponds to a pre-determined engine RPM at which it is desired to disengage the starter; and (3) has a hysteresis network to prevent subsequent re-energization of the starter relay until the AC signal from the alternator drops to a value substantially below the original threshold frequency, preferably when the engine is stopped or almost stopped, whereby the starter switch will re-energize the starter relay only if the master switch is closed and the engine is not running.

Failsafe primary power control apparatus for systems using computer controlled power sequencing

Abstract: Failsafe primary power control apparatus is provided which includes a backside contact of a control relay in series with the power relay which is held open until the initial program load and latch reset is finished. The system also includes a timer which is initiated by a power fault condition signal which is simultaneously applied to the processor. If the processor is capable of handling the fault condition, it puts out a signal which stops the timer. If the processor is not capable of handling the fault, the signal to the timer is not produced and, accordingly, the timer runs the full interval. This causes the backside contact of the control relay to open thus deenergizing the power relay and removing the power from the entire system.

Control system for accumulating conveyor

Abstract: A control system for an accumulating conveyor having a plurality of zones, wherein each zone includes an improved pneumatic logic module comprising a relay limit valve and an AND valve, the output of the AND valve being connected to a driving input of a fluid motor for transmitting power to the corresponding zone of the conveyor. A pilot operated relay valve is connected to the first zone and employed to release an item thereon. The control system can be easily modified to provide forward or reverse accumulation, and single or train release. Additional pilot operated relay valves are employed for selecting between forward and reverse accumulation and single additional pilot and train release modes.

Solid state relay

Abstract: A solid state relay for interrupting current flow in a power distribution circuit is disclosed. The relay includes a long time delay circuit which generates a first trip signal when the magnitude of the peak instantaneous line current rises above a pickup value I1 for a time period which varies as an inverse function of the magnitude of the peak instantaneous time current and which is determined by a first predetermined time current characteristic curve. The first predetermined time current characteristic curve defines the desired operating characteristic of the relay over a first current range extending between the pickup current I1 and the higher current I2. The predetermined time current characteristic curve is determined by a multi-node RC element in the feed back loop of an operational amplifier which forms part of the long time delay circuit.

Test apparatus for checking the response of protective relays

Abstract: A test apparatus for checking test objects, such as protective relays, especially voltage, current and/or frequency relays for the protection of a generator of a power supply network, comprising a first circuit for generating and converting test signals or magnitudes to be delivered to the test objects and a second circuit for pre-programming the test signals or magnitudes to be delivered to the test objects. The first circuit comprises a first test signal generating circuit for supplying the voltage relay and the current relay with voltage and current test signals, respectively, and contains a first secondary winding of a test transformer. A static potentiometer is connected in parallel with this first secondary winding. The potentiometer supplies test signals in finely stepped or graduated values to the test objects. The first circuit further comprises a second test signal generating circuit for supplying the frequency relay with frequency test magnitudes. The second circuit embodies a test matrix composed of intersecting electrically conductive rails. The test matrix stores information concerning the test signals to be delivered to the relays. A signal and control device operatively connected with the test matrix and receiving therefrom the stored information concerning the test signals stores a predetermined course of the test program and correspondingly controls the performance of the test.

Method and apparatus for controlling vehicle directional lamps

Abstract: An improved method and apparatus for use in the direction indicating system of a vehicle having a group of front, rear and side directional lamps The directional lamps are connected in parallel with each other to be energized by a battery through a current detecting resistor, a normally-closed relay and a selection switch The relay is energized to open periodically in response to a train of pulses so that the directional lamps flash periodically during closure of the selection switch Closure of the selection switch is detected in response to the voltage across the current detecting resistor to generate the pulses applied to the relay

Adjustable time delay relay

Abstract: An adjustable time delay relay is provided which is particularly suitable for automatic transfer switches and other applications requiring a relatively long time delay during periods when electrical power is not available The relay includes a relay coil connected across a large storage capacitor supplied from an AC power source through a diode The timing function is provided by a separate timing capacitor which, upon discharge through an associated adjustable resistor, operates a switching transistor to establish a low impedance path across the relay coil, thus discharging the storage capacitor and de-energizing the relay Such a construction eliminates the need for a close tolerance, high value storage capacitor and provides a high degree of time delay reproducibility despite variations in power supply voltage

Method and apparatus for fuel ignition system including complete cycling of flame relay prior to trial for ignition

Abstract: When a call for heat is established, a flame relay is actuated for a predetermined time by means of a cycling timer. Upon this initial actuation, the flame relay inhibits a checking relay and initializes a trial-for-ignition (or simply "ignition") timer. After the cycling timer times out and the flame relay has been completely cycled, which established operativeness of the flame relay and flame sensing circuitry, the checking relay is enabled and actuated for the ignition period. The checking relay then actuates the pilot valve and a spark generator to start a pilot flame. If a flame is sensed, before the ignition timer times out, the flame relay actuates the main valve and establishes a holding current for the ignition timer so that the checking relay continues to be energized. If a flame is not sensed during the trial period, the ignition timer disables the checking relay, thereby de-energizing the pilot valve before the main valve is opened. If there is a fault in the flame relay or flame sensing circuitry, the checking relay is inhibited from operating. Both timers are preferably electronic timing circuits using capacitors in such a manner that circuit faults do not cause system malfunction. In an alternative embodiment, separate flame sensing circuits control the operation of the flame relay and the ignition timer.

Vital power varistor circuit for railroad signaling systems

Abstract: A vital circuit network, equivalent to a two element, alternating current track relay used as a synchronous detector, has a first input transformer directly coupled across the local track circuit source and second input transformer coupled across the track rails through a band pass filter tuned to the track circuit frequency. The transformers are designed to normally produce secondary output signals of the same range, which are connected into a series circuit network including a second band pass filter, a varistor, a full-wave rectifier, and a protective fuse, with a biased track relay connected across the rectifier D. C. output. From the two voltage signals in the series network, the varistor produces a product current signal which is rectified to provide an output sufficient to pick up the track relay only when both input signals are present, are of the track circuit frequency, and are within a predetermined phase relationship. The varistor circuit network has a sharp rejection of input signals outside the predetermined phase relationship or of a nonselected frequency.

Vital relay driver having controlled response time

Abstract: A vital relay driver whose response time can be readily controlled such that the release time of the relay may be varied, yet may be held to very close tolerances. The vital relay driver is controlled by a microprocessor dedicated to this function, such processor generating a dynamic signal of fixed frequency in dependence on a cycle number which is continually replenished; otherwise the microprocessor stops producing the dynamic signal and the relay is released in a closely known time.

Pluggable miniature relay

Abstract: Pluggable miniature relay comprising a plug-in socket connector; the base of which has a complementary configuration to that of the base of the relay. Two walls of the connector ensure the housing of the contact springs which are soldered by an end on the mounting support (printed circuit board) and set up by the other end the electric contact with the relay electrodes. The other two walls have locking studs which home in the recesses of the relay cover, when the relay is plugged-in on the socket connector, and hold it locked on the latter.

Motor Statring Protection by Impedance Sensing

Abstract: A linestart induction motor, when protected against locked rotor by a time overcurrent relay, can be tripped off during a normal start under some conditions of load inertia and voltage. Such failure to start can occur even when the relay appears to be correctly set. To prevent it the relay should be disabled at a time after rotation begins and before the relay can operate. A speed sensing switch can supervise in this way but requires direct access to rotating parts, sometimes not feasible or not economical. Impedance sensing offers an accurately setable alternate means by direct relay monitoring of voltage, current and phase angle without requiring access to rotating parts.

Protective circuit for control of capacitor motor - has monitoring relay which drops out, independently from mains voltage fluctuation, when speed drops and/or on excessive torque

Abstract: The protective control is speed and/or load dependent, and the motor concerned has several phase windings, and can be connected to the mains through a switch monitored by a relay. The motor (M) or its capacitors (9) is in a secondary circuit (17) with a rectifier (G12) controlling the mains switch relay (18) with a control resistor (R5) and a Zener diode (ZD3). In order to compensate for mains voltage fluctuations, a stabilising circuit (12) - with a voltage divider (14) - is provided, so that the relay (18) drops out, when the motor (M) is connected to the mains - independently from mains voltage fluctuations - and relay holding voltage value is not reached owing to drop in motor speed and/or excessive torque.

Latching relay circuits and analog to digital converters

Abstract: The variable attenuator and variable current shunt of a battery-powered auto-ranging digital multimeter uses latching relays, each of which, since it is stable in each of its two switching states, requires only a current pulse to change its state. The circuit which operates the relays provides a drive pulse only when the desired relay state differs from the actual state, thus minimizing the power required, and includes a tank circuit for minimizing disturbance to the multimeter power supply. To ensure that the tank circuit can recharge, each relay is driven by a tri-state output.

Synchronizing check relay

Abstract: A synchronizing check relay is used in an electrical transmission network for controlling a circuit breaker to interconnect first and second transmission lines to establish power flow therebetween and includes an input circuit for receiving signals from first and second transmission lines. A phase difference generator generates a phase difference signal proportional to a phase difference between said signals from said first and second transmission lines. A phase difference comparator receives the phase difference signal and produces a phase output signal at a selected phase condition. An adjustable timer produces a timer signal after a selected time interval in response to the phase comparator to insure a proper phase difference between the transmission lines. The voltage sensor produces a breaker closing inhibit signal when one of the alternating current voltages is outside a reference limit. A control circuit is responsive to the phase output signal, the time signal and the breaker closing inhibit signal for providing a control response to the circuit breaker.

Offfdelay timer circuit

Abstract: PURPOSE:The AC power source is connected to the series circuit which consists of a diode, the operating coil of a two-winding latching relay and a constantvoltage element , so that the normal OFF-delay operation can be executed even if the power on time is short.

Electromagnetic valve security device for fuel supplies

Abstract: An electromagnetic valve circuit used in a fluid line security device is disclosed. The circuit is adapted to open and close a fuel supply pipe. The circuit includes an attracting circuit and a holding circuit connected to one side of a power source. The attracting circuit including an attracting switch is in parallel with the attraction holding circuit. The attracting switch is closed only when the attraction phase of value opening is to be accomplished. In one modification the series circuit of the attracting switch and the electromagnetic valve circuit is coupled in parallel to a circuit formed by a hazard detecting switch, and a relay switch operating coil. In another modification a time limit current control is connected in series with the valve coil to control the supply of current to the coil for a predetermined time limit.

Electromechanical anti-theft system for automobile vehicle

Abstract: Electrovalves are opened in automobile piping of a brake line, a clutch line and a fuel line by a current through normally open contacts of a plurality of control relays and through normally closed contacts of an interlocking relay. The control relays are operated by selected switches of a plurality of push-button switches while the interlocking relay is operated by the non-selected switches of the plurality of switches. The control relays are interconnected so that the selected push-button switches must be operated in a selected sequence. All the relays have holding circuits.

Receiving circuit of fire alarms

Abstract: PURPOSE:To flow the rush current flowing to sensors when a power supply is switched on to resistors and to operate a relay when this current runs out by providing a bypass circuit using resistors in parallel to a receiving relay and providing a delay circuit to the power supply input side

Electromechanical relay with manual override control

Abstract: An improvement in a standard electromechanical relay wherein a manually shiftable member simultaneously disconnects the operating coil of the relay and mechanically shifts the relay into an actuated or released condition.