Showing papers on "Relay published in 1975"

A three-phase differential relay for transformer protection

Abstract: Established harmonic restraint differential relay concepts have been enlarged upon to provide a new static multiple-winding transformer differential relay. The resulting design includes simplification of the frequency selective circuits and new techniques for rapidly determining the harmonic content of the applied currents. The relay is shown to have improved sensitivity, to be responsive to internal transformer winding faults in less than two cycles, and to the more severe type of fault in less than one cycle. Full security against inrush currents and overexcitation as well as to external faults is demonstrated. Poor performance of current transformers is shown not to adversely affect either the security or dependability of the relay. Heavy current test results are presented which confirm the relay principles.

Protective relay circuits

Abstract: A protective relay circuit. An electrical system signal quantity is monitored and applied to a filter and to a bipolar threshold device in parallel with the filter. The bipolar threshold device has a zero output signal level as long as the magnitude of the monitored signal is less than some predetermined value. When the monitored signal exceeds the predetermined value, the output of the bipolar threshold device will be substantially equal to the monitored signal level minus the predetermined value. The output of the filter and the output of the bipolar threshold device are combined in a summing amplifier to provide a signal for controlling the trip coil of a circuit breaker. When the circuit is used in an overcurrent or overvoltage protective relay, the combined signal is rectified and applied to a level detector which provides the signal for controlling the trip coil of the circuit breaker. When the circuit is used in a distance or directional relay, the phase of the combined signal as compared to the phase of a second monitored signal determines the generation of the signal for controlling the trip coil of the circuit breaker.

Automatic exclusion circuit

Abstract: A relay is included in a subset of a key telephone system to connect the subset to a line selected by the line button of the system when the relay is activated. A control circuit is coupled to the relay and a key system positive ground to control the operation of the relay. The "A" lead of the key telephone system is coupled to the control circuit to disable the control circuit and, hence, the relay when the positive ground is coupled into the subset on the "A" lead and to enable the operation of the control circuit and, hence, actuation of the relay when the positive ground is not coupled into the subset on the "A" lead.

Adaptive relay control of second-order systems

Abstract: The adaptive relay, control of single-input second-order systems is considered. The plant parameters are assumed constant, but unknown. The controller dispenses with a learning (or identification) phase and does not organize itself through adaptive correction, but identifies a certain curve in the state space. This curve is associated with sliding motion. The strategy is analysed for the double-integrator plant. The identical controller can be applied to other second-order plants. The system response is found to be close to the time-optimal response.

Protection circuit for battery powered electronic devices

Abstract: A rechargeable battery provides a source of operating potential for an electronic circuit load. An operator controlled on-off switch connects the battery to a relay, and through the normally open relay contacts, to the electronic circuit. The relay winding is returned to ground through a capacitor. When the switch is closed the relay is momentarily energized by the current which charges the capacitor. A transistor has its collector-emitter path in parallel with the capacitor and its base coupled to the movable tap on a voltage divider connected across the load. In the absence of a low voltage condition across the load, the transistor conducts maintaining relay closure for normal circuit operation.

Semiconductive devices with integrated circuit switches

Abstract: A bilateral, switching integrated circuit is described in U.S. Pat. No. 3,918,083. The present application discloses variations of the basic structure and devices incorporating both the basic structure and the variants. Included are a photosensitive, zero-crossing optoisolator, relay structures, a switch of greatly increased light sensitivity employing photodarlingtons, and a dielectrically isolated switch that can be triggered by light or gated injection currents.

Relay station in a telecommunications transmission system

Abstract: A relay station for use in a communications transmission system, and particularly well suited for use in an earth satellite, employing a common carrier source for supplying carrier to a plurality of superheterodyne transmitters at a power level which is low compared to the total power required by the transmitters and a further carrier to be used as a beacon signal.

Back up alarm system

Abstract: Electrically conductive leads electrically connect a relay, a source of electrical energy and a radio transmitter for transmitting radio signals in a back up circuit with a burglar alarm. The relay is electrically connected to the electric circuit of a burglar alarm system and is maintained unenergized by said system so that the relay is normally open. When an electrical conductor of the burglar alarm circuit is energized, the relay is energized and closes the back up circuit to actuate the transmitter to transmit radio signals indicating that an electrical conductor of the burglar alarm circuit has been energized.

Methods for estimating transient performance of practical current transformers for relaying

Abstract: Since engineers learned, about 50 years ago, that a current transformer has real difficulty with an initially fully offset transient current, they have written many papers about the difficulty without finding a solution for most practical relay problems. This paper offers new data and methods which are intended to lead the relay engineer to solutions to many problems and to give him a better insight toward proper action in cases where there is still no simple solution. The emphasis is on practical problem solving. Some of the assumptions which are made can be defended on the basis that the solution, however much in error, errs on the safe side, and that the solution is a most valuable guide to the relay engineer.

Solid state replacement for a mechanical relay

Abstract: A direct replacement for mechanical relays without requirement for modification of associated circuitry and circuit connections. A standard relay base having a standard relay pin configuration is utilized for mating with a standard relay socket connected to the associated circuit. A control circuit is mounted on the base and connected to the relay pins and the base. A cover is provided which fits over the base and contains the control circuit. The cover has externally accessible cover terminals mounted therein connected to the control circuit. A remote heat sink is provided for mounting remotely from the relay base and socket for carrying a solid state triac device having a gate and first and second main terminals connected by electrical conductors to the cover terminals. The control circuit is configured to receive a command input signal and a power input signal. The command input signal enables the control circuit, so that the power input signal provides a trigger output coupled to the triac gate. In this fashion, the command input signal controls current between the first and second main terminals of the triac when a load voltage is impressed thereacross.

Vehicular electrical safety apparatus

Abstract: This disclosure pertains to apparatus mounted to the frame of a vehicle, sensitive to impacts exceeding a predetermined level. The impact device disables a main control relay which feeds all of the electrical circuitry of the vehicle. Turning the ignition switch to the "off" position also de-energizes the main control relay in the same fashion as the impact device further insuring that all electrical circuits in the vehicle are fully disabled.

Hold circuit for telephones

Abstract: A hold circuit for telephones which includes a relay having a coil and normally open contacts. A normally open momentary contact switch is connected in series with the relay coil, the series combination being connected across the telephone lines. The contact switch is connected in parallel to the normally open contacts of the relay. The hold circuit captures or holds the telephone lines when the contact switch is closed and permits the telephone lines to be released upon removing the telephone handset "off the hook." In one embodiment, a parallel connection of a lamp and a capacitor is connected in series between the relay contacts and the relay coil to form a voltage divider when the relay contacts are closed.

Motor vehicle headlight control apparatus

Abstract: In a vehicle having an ignition switch, headlights and a storage battery, a relay has its winding in series with the battery and the collector-emitter circuit of a transistor and has normally open contacts in a headlight energizing circuit. A resistance-capacitance time delay circuit, connected with the ignition switch, controls bias of the transistor. Hence the transistor conducts whenever the ignition switch is "on" and for a short time after it is turned off; and while it conducts, the relay contacts are closed and the lights are energized.

Device for measuring breaking time of relay

Abstract: PURPOSE: To apply current corresponding to the breaking current of a relay to the primary winding of a current transformer through the relay, thereby accurately measuring the breaking time of the relay. COPYRIGHT: (C)1977,JPO&Japio

Nerve and muscle stimulator - gives stimulus currents varied with location and time from switching logic and relay chain

Abstract: Nerve and muscle stimulator, for spatially and time-variable stimuli, has a current generator and more than 2 electrode outputs, with relay contacts of a relay chain, in series or in parallel with the object to be stimulated, and a switching logic as a continuously-running ring counter, pref. as a diode matrix, to control the relay chain. Preferably, to stimulate the phrenic nerve, a low-frequency pulse generator simulates the respiratory cycle and controls both the ring counter and the amplitude of the stimulus current generator. There may be a number of current regulators for independent adjustment of the stimulus current, corresponding to the number of possible electrode combinations.

Control circuits for vehicle rear window heaters

Abstract: A vehicle rear window heater control comprises a touch switch, a bistable circuit driven between its two states by the touch switch, a relay operated by the bistable circuit so that the heater is controlled by the touch switch and a monostable circuit triggered by the relay for switching off the bistable a predetermined time after the touch switch has been actuated to energize the heater.

Generator protection with a new static negative sequence relay

Abstract: This paper describes the development of a new static negative sequence relay for generator protection. This relay has a broader range of settings and greater sensitivity to provide protection for modern large generators as well as units in unattended stations, such as remote-controlled hydro and gas turbine peaking plants. An example is given of its application, in light of newly proposed ANSI standards.

Fluid operated electrical relays and systems

Abstract: Low-cost fluid-operated electric relay type logic elements are provided with an elastomeric conductive diaphragm flexed out of a stable taut intermediate position by means of differential pressures of fluid signals directed into respective chambers on opposite sides to provide thereby break or make connections with cooperating conductive contacts. Thus fluid logic, switching circuit logic or hybrid logic operations may be effected directly with attendant advantages of reliability and more powerful logic capabilities. Alternatively the elements may serve as interfacing members to produce electrical signals from fluid systems. The elements have further advantages as servicing monitor means where access is provided to conductive circuits displaying more servicing information relating to operational characteristics of the fluid logic devices than possible with fluid indicators.

Controlling apparatus for driving gear in suction cleaner

Abstract: A controlling apparatus for the driving gear of a suction cleaner equipped with a container accommodating a suction fan together with a motor for actuating said fan, a suction hose, and a device for the paying-out and hauling-in of said suction hose together with a reversible motor for actuating said device, both of said motors being supposed to be controlled by means of controlling circuits to be actuated by a switch disposed near the fore end of said hose through a couple of lead wires buried in the hose, wherein said controlling circuits for these motors are respectively provided with three relays for actuating the respective motor and three switches for actuating said relays as incorporated therein, two of three circuits thus combined with said relay and actuating switch corresponding therewith are respectively provided with AC half-wave rectifiers having opposite polarities while the remaining one circuit is provided with contacts to be controlled by two relays included in said two circuits.

Differential switch for detecting leaks

Abstract: A flapper is provided in the inlet and outlet lines to a domestic hot water heater or the like and a permanent magnet is affixed to the bottom portion of each of the flappers. Immediately adjacent each flapper and outside of the pipe, a magnetically operated switch is placed. The magnetically operated switches are connected in circuit with a relay which in turn controls a solenoid valve for cutting off or permitting the entry of water from the source into the inlet pipe. Under normal operating conditions when there is a flow of water in the inlet pipe and the outlet pipe the connection of the magnetically operated switches is such that the relay will not operate and the solenoid actuated valve will be open permitting the entry of water from the source. When a leak occurs, the ensuing movement of the flappers caused by the change in liquid flow will operate their associated magnetic switches, causing the relay to be actuated and closing the solenoid actuated valve, thus cutting off the supply of water. A thermal time delay switch is incorporated in the circuit to prevent the actuation of the magnetic switches in response to "water hammer" or the like.

High voltage relay package

Abstract: A small size high voltage relay package for low voltage control of high voltage lines. The relay package includes a reed switch surrounded by a polytetrafluroethylene tube around which is wound a coil for operating the reed relay. The entire structure is positioned within a casing which is potted with a polyurethane potting material which also extends over the coils and into the space between the sleeve and relay to provide complete encapsulation. The system is capable of handling voltages in the vicinity of 20kv utilizing a 24 volt switching source.

Overload protective cct. breaker - has socket with switching contacts as separate component module with integral support

Abstract: The circuit breaker protects against defective current or voltage with corresponding tripping. It is provided with a socket retaining the switching contacts and the terminals, in which is also mounted the contacts actuating shaft in a rotary manner. The shaft is connected on the side to a switching latch with a toggle lever, and on a other hand to a trip actuated by a relay armature. The relay coil is connected to a current of voltage transformer, according to the breaker design. The assembly has a cover cap with a push-button switch in the tripping circuit. The socket is in the form of a separate component and carries a support element in the form of an integrated module, containing the switch latch with the switching lever, the toggle lever arrangement and trip, the relay and the setting elements. The support element is arranged next to the transformer, but separated from the same.

Two coil relay for dryer with integrated circuit control

Abstract: A fabric treating appliance, such as a clothes dryer, has four different modes of machine operation which are controlled by an integrated circuit having two outputs in conjunction with a moisture sensing means and a sensor circuit; and relay circuitry is provided to interface between the integrated circuit and the power circuit of the machine. This relay circuitry includes two coils operably associated with switching apparatus so as to achieve four distinct control states corresponding to the four different modes of machine operation. A like relay circuit may be adapted for use on a machine having a three-output integrated circuit control.

Fail-safe energizing circuit for a functional device

Abstract: A fail-safe energizing circuit for effecting the operation of a functional device, such as a relay, includes a resistor and a capacitor connected between outputs of an AC signal source which supplies an AC signal for charging the capacitor, a normally disabled silicon controlled rectifier connected in shunt with the capacitor and an operate coil of the relay and operable when enabled to provide a discharge path for the capacitor permitting the capacitor to discharge over the relay coil to operate the relay, and a control circuit operable to provide an enabling signal derived from the AC signal for enabling the silicon controlled rectifier. The energizing circuit is described with reference to an application in an automatic fuel ignition system for controlling the operation of a relay which energizes a fuel valve of the system.

Vehicle anti-theft alarm system

Abstract: An electrical-electronic circuit for operating the horn and headlights of a car in a manner which will give audible and visual warning of a theft attempt. The circuit includes a suitably located tamper switch for each door or other closure member of the car and a number of electronic devices which combine with the tamper switches to control the flow of current between a master switch and a relay switch. The master switch is associated with one of the car door locks and this normally open switch is closed to arm the circuit whenever the key is turned in the lock to secure the door.

Capacitor discharge of latching relays and rotary filter

Abstract: Direct current circuitry for sequentially energizing two or more motors orther load devices, using capacitive discharge to latch in a relay for each load device. During one stage of operation a relatively small voltage is impressed on one lead of a capacitor whose other lead is grounded; a charge is thereby developed in the capacitor. Subsequently a relatively large voltage is impressed on the other lead of the capacitor to direct the charge into the coil of the relay, thereby effecting a relay latching action. The capacitor thereafter isolates the latching circuit from a de-latching circuit; the de-latching circuit is part of a latching circuit for a second relay used to energize a second load device. The invention is particularly useful in sequentially operating electric motors used in self-cleaning engine air cleaners.

Electric circuit for selecting operational conditions of load

Abstract: A wiper switch is connected to a wiper motor through a relay switch and further to a switch condition discrimination circuit which produces a trigger signal when the wiper switch is actuated from the closed state to the opened state and again to the closed state within a fixed time. A multivibrator is connected to the switch condition discrimination circuit and begins to oscillate upon receiving the trigger signal. The relay switch connected between the wiper motor and the wiper switch is actuated to open when receiving the oscillation pulses from the multivibrator, whereby the wiper motor is intermittently supplied with the electric power to perform the intermittent wiper operation.

Single bus DC control circuit

Abstract: A DC control circuit supplies direct current of either polarity at a high or a low level to a crane hoist or the like via a single bus bar to control up, down, low or high speed functions. A network of diodes and ganged switches at a remote control panel supplies the selected level and direction of current to the bus bar while a control circuit moving with the powered equipment responds to the voltage level and polarity picked off of the bus bar by means of a high voltage responsive relay coil circuit and dual, parallel, diode, relay coil circuits responsive to polarity.