Showing papers on "Relay published in 1971"

Wired broadcasting systems

Abstract: In a wired broadcasting system the switching means for selecting one of a plurality of program sources is a set of electromagnetic relay switches each having two operating coils connected into different switching circuits. Switching is accomplished from a train of pulses actuating thyrister circuits to operate selected sets of coils. In one embodiment three wires provide selection signals to three different relays having a common second winding circuit and energization of two coils on each relay is necessary to operate a selection switch set. By choice of sets of pulses by a dialing mechanism to energize two circuits having the different wiring patterns through the coils one of nine relays may be operated for a selection. The dial pulsing mechanism is operated twice to select one program defining one set of three relays and one of those three respectively.

Solid state relay circuit with optical isolation and zero-cross firing

Abstract: A solid state relay circuit is provided which has four terminals, two for power input, and two for signal input. The circuit consists of a full-wave diode bridge circuit having a pilot thyristor connected across its D.C. terminals. A firing control circuit also energized from these bridge terminals applies a firing signal to the thyristor gate responsive to the receipt of an input radiation signal from an optically isolated signal circuit connected to the signal input terminals, and causes the delivery of a firing signal to a thyristor or triac when the input voltage is near or at zero. Thus, the thyristor or triac in the relay output circuit begins to conduct under zero voltage conditions.

Data-Aided Carrier Tracking Loops

Abstract: An innovation which improves the capability and performance of certain types of phase-coherent demodulators is introduced. This innovation has application in the fields of telemetry and tracking, e.g., relay satellite systems, deep-space communications, and military communication systems. The basic idea of the innovation centers around using the power in the composite signal sidebands to enhance the demodulator's effective signal-to-noise ratio (SNR). The vehicle through which this is accomplished employs the principle of decision-directed feedback. In its simplest form it is shown, for the first-order loop, that the maximum improvement in loop SNR relative to a standard phase-locked loop is 10 dB. The paper explores and illustrates the corresponding improvement realized in detection system efficiency. Extension to higher order loops follows directly from the analysis given here.

Current limited battery pack

Abstract: A battery pack includes a resettable protection circuit for limiting the current to a load, which includes a normally nonconductive silicon controlled rectifier and a magnetic reed switch serially connected across a battery. When excessive load current develops, the silicon controlled rectifier is rendered conductive which in turn cuts off a regulating transistor or energizes a relay to prevent current flow to the load. The battery, magnetic reed switch, silicon controlled rectifier and regulating transistor or relay are encased in a sealed container to prevent sparks and arcing and allow usage in a hazardous atmosphere. The silicon controlled rectifier is reset, to allow continued usage of the battery, by actuating the reed switch with an externally supplied magnetic field. Actuation of the reed switch breaks the current path to the silicon controlled rectifier.

Solid-state relay using light-emitting diodes

Abstract: A solid-state relay utilizing a light-emitting diode to transmit optical energy steadily to a photo-sensitive solid-state device to control the conductivity of solid -state elements. A relatively low power source of AC or DC can be used to operate photo-sensitive uni-junction transistor or a pair of light-activated silicon-controlled rectifiers.

Solid-state relay

Abstract: There is disclosed an improved solid-state relay comprising a C-MOS analog switch or transmission gate in which the change in input-output resistance for variations in the input signal is minimized by maintaining the substrate of the N-channel device at the same potential as that of the source of the N-channel device. The N-channel substrate provision source are maintained at the same potential by the privision of an additional P-MOS device located on the same integrated circuit chip in which the additional P-MOS device is rendered conductive during that period of time which the switch is in its conducting mode.

Solid state relay using photo-coupled isolators

Abstract: A solid state relay coupled to provide current flow to a load from a high voltage source provides high isolation between the relay''s output terminals and an input control gate by means of a photo transistor coupled pair and a photo silicon controlled rectifier coupled pair connected in series circuit for response to the input control gate and by means of an output transistor responsive to the series circuit for providing a current path from the high voltage source through one output terminal, the collector-emitter path of the output transistor and to a load via the other output terminal.

Displacement control system for hoist apparatus

Abstract: A displacement control system for hoist apparatus, in which the winch is driven by a drive which is controlled by a pneumatic signal derived from a pressure controller, the controller output pressure signal being determined by comparing in a computing pneumatic relay variable signals derived from a relative motion responsive reference sensor, a load position sensor, and a speed sensor.

Feed rate controller

Abstract: An apparatus to eliminate the stalling of a machine tool spindle electric drive motor when a cutting tool secured in the spindle encounters a hard spot in a workpiece. A current relay is connected in the spindle motor circuit and is energized upon the occurrence of an abnormal load on the spindle motor. A normally closed contact of the relay is located in the feed axis drive system and effects the interruption of the command pulses to the feed axis drive system.

Control device for electromechanically operated closure panels

Abstract: A control device for a motor-driven closure panel, for instance an automobile sunroof panel whose closed position is an intermediate position between an open, retracted position and another open, pivoted position, the circuitry for the reversible motor including an impulse relay operating a control switch in one of the two motor connections, the relay coil being connected in parallel to the motor and between the control switch and the pole reversing switch, a position-responsive switch cutting off the relay circuit whenever the panel moves out of its closed position and energizing the impulse relay whenever the panel reaches the closed position.

Flame sensor control circuit

Abstract: Control apparatus featuring a condition sensor, a first relay responsive to a signal from the condition sensor, the first relay being in a first state in the absence of a signal from the condition sensor and being switched to a second state in response to a signal from the condition sensor, a control relay adapted to be switched between first and second states, circuitry responsive to an operation request for switching the control relay from the first state to the second state after a time interval, and clamping circuitry operative in response to the detection of the first relay in its second state during the time interval to clamp the first relay in the second state and the control relay in the first state, overriding the influence of the condition sensor on the first relay

Mine power system ground continuity check circuit

Abstract: A ground cable continuity check circuit for a power supply cable system having a grounding and a pilot conductor electrically interconnected remotely from the power supply. A source of electrical energy for the check circuit is provided through a constant current transformer having its secondary connected between the grounding and pilot conductors. A circuit including the coil of an undervoltage relay and the contacts of a current relay is connected across the constant current transformer primary. The current relay coil is connected in series with the constant current transformer secondary and the grounding and pilot conductors. A voltage breakdown device is connected across the constant current transformer secondary to divert current from the current relay coil when a high impedance appears in the ground circuit for opening the current relay contacts to disable the under voltage relay. The power supply system may have a main cable and at least one branch cable in which case the grounding and pilot conductor loops of the main cable and branch cable are interconnected by a current transformer having one coil connected in the main grounding and pilot conductor loop and the other coil connected between the grounding and pilot conductors of the branch circuit.

Voice switched microphone control system

Abstract: Voice activated control apparatus selectively connects one of a plurality of microphones to an audio line and inhibits all other microphones from capturing the line while the initial connection is maintained. Each microphone is connected to an associated speech detector and relay. In response to voice signals from a microphone, the associated speech detector activates a relay which connects the microphone to the line and generates a signal which inhibits the other relays. Other users cannot interrupt the present speaker because their relays remain inhibited as long as the speaker continues. The same circuitry can accommodate any number of microphones.

Control arrangement for an air heating apparatus

Abstract: An improved control arrangement for an air heating apparatus having a multi-volt electrical power source, a power control circuit for energizing air blower means and air heating means, and a safety control circuit for de-energizing the power control circuit in response to an unsafe operating condition. The safety control circuit includes a thermoelectric generator which is activated by heat emitting means disposed within the power control circuit. The safety control circuit further includes a relay actuating winding in series with the thermoelectric generator, the relay actuating winding actuating a relay switch means. The improvement is in the relay switch means which includes a parallel combination of a normally closed switch and dropping resistor, the combination being in series with the heat emitting means so that when the relay switch means is actuated the heat emitting means is subjected to reduction in heat output.

Switch control arrangement for railroad classification yards

Abstract: The central data processor controlling the automatic switching system also compares the initial axle count, registered when a car enters the yard, with the axle count for that car from a wheel detector in the approach to each switch along the selected route. As long as the compared counts are not equal, the data processor holds energized an added detector relay. Back contacts of this relay interrupt the switch control circuit network to inhibit switch operation to the position selected for the next car, in the same manner as switch detector track circuit relay contacts are used. Thus the switch is locked against movement, not only when the associated track circuit is occupied but by lack of comparison between the axle counts if the track circuit is spanned, and full operating safety is maintained even with long cars. Blocking jacks for each storage track are provided in the track diagram on the yard control console. Insertion of a plug into a jack, to block further entry of cars in that track, activates a circuit network which bypasses and thus inhibits control of the key switch for that track by the data processor. Rather the key switch is positioned and held, overriding all other controls, to route all approaching cars away from the route to the blocked track or tracks.

Ground fault circuit interrupter

Abstract: A ground fault circuit interrupter and/or indicator comprising a relay switch and/or indicator lamp connected on one side to the grounded frame of an appliance or other part, and on the other side to the neutral wire or to the grounding wire of the electrical service. Current leaking from the hot line to the appliance frame due to moisture or faulty insulation passes through the relay coil and/or indicator to the neutral line or grounding wire of the service, and this actuates the relay switch to open the hot line circuit to the appliance. In one embodiment, there is an additional circuit breaker in the hot line comprising a relay switch serially connected to the hot line, which is energized by excessive current flow, as in a line-to-line short.

Refrigerant compressor motor control

Abstract: A REFRIGERATION SYSTEM HAVING AN ELECTRIC MOTOR DRIVEN RECIPROCATING COMPRESSOR IS PROVIDED WITH A MOTOR PROTECTION AND CONTROL SYSTEM. THE MOTOR PROTECTION AND CONTROL SYSTEM INCLUDES A MOTOR CURRENT SENSOR FOR SENSING MOTOR CURRENT, A TEMPERATURE SENSOR FOR SENSING DISCHARGE GAS TEMPERATURE FROM THE COMPRESSOR AND A THERMOSTAT FOR SENSING ROOM TEMPERATURE. THE SIGNAL PROVIDED FROM THE CURRENT SENSRO IS SUMMED WITH AN OPPOSITE POLARITY RESET SIGNAL AND INTEGRATED TO PROVIDE AN INPUT SIGNAL TO A FIRST TRIP CIRCUIT. WHEN THE INPUT TO THE FIRST TRIP CIRCUIT EXCEEDS A PREDETERMINED VALUE, A SOLID STATE SWITCH MEANS DEENERGIZES A RELAY WHICH DISCONNECTS THE MOTOR FROM THE LINE CURRENT SOURCE. THE TEMPERATURE SENSOR IS CONNECTED TO A SECOND TRIP CIRCUIT WHICH IS ALSO CAPABLE OF DE-ENERGIZING THE RELAY AND THE MOTOR IN THE EVENT OF AN EXCESSIVE TEMPERATURE CONDITION. THE THERMOSTAT IS CONNECTED TO A THIRD TRIP CIRCUIT IN A MANNER SUCH THAT OPENING OF THE THERMOSTAT CONTACTS DE-ENERGIZES THE SOLID STATE SWITCH AND RELAY. CLOSING THE THERMOSTAT CONTRACTS PASSES A SIGNAL THROUGH THE SOLID STATE SWITCH MEANS TO ENERGIZE THE RELAY PROVIDED THE SWITCH HAS BEEN RESET TO THE CONDUCTING CONDITION. FEEDBACK MEANS ARE PROVIDED RESPONSIVE TO THE NON-CONDUCTING CONDITION OF THE SWITCH TO RAISE THE OUTPUT OF THE INTEGRATION CIRCUIT AND ADDITIONAL FEEDBACK MEANS ARE PROVIDED RESPONSIVE TO THE NONCONDUCTING CONDITION OF THE SWITCH TO DECREASE THE THRESHOLD OF THE TRIP CIRCUITS. THE FEEDBACKS PROVIDE A RESET LEVEL FOR THE SYSTEM WHICH IS LOWER THAN THE INITIAL TRIP LEVEL AND TO IMPROSE A TIME DELAY ASSOCIATED WITH THE FIRST TRIP CIRCUIT ON RESETTING THE SYSTEM AFTER A TRIP DUE TO OPENING THE THERMOSTAT CONTACTS. D R A W I N G

Means for dual level ground fault protection of a.c. circuits

Abstract: Circuitry for detection of ground fault currents in alternating current circuits utilizable with grounded or ungrounded systems and for protectively interrupting the circuits, comprises means for deriving monitoring signals from representative of the fault currents and applying the signals to first and second relays. The first relay is responsive at a low level of fault current to pass control current from a source of control power to warning such as a lamp and horn. The second relay is responsive at a higher level of fault current to pass control current to an interrupter device for the circuits being monitored. Adjustment means in the circuitry sets the two threshold levels of fault current at which the relays respectively respond. Seal-in circuit means keep the first relay actuated to activate the alarms continuously after their operation is initiated. A time delay network prevents relay response to instantaneous transient currents exceeding the lower threshold. The circuitry is unitized for use at any standard voltage, current and frequency and to isolate all current carrying components. The circuits being monitored can serve as a source of control power or an independent source can be provided.

Temperature responsive control switch with bi-metallic disk means

Abstract: A temperature-compensated gas density relay includes a bellows unit subjected to the gas, the pressure from which is transmitted by the bellows unit through a support mounting a bi-metallic disc and a shaft carried by the central portion of the bi-metallic, and longitudinal displacement of the shaft in response to the change in gas pressure serves to actuate the contacts of an electrical switch component of the relay. Should there be a change in the gas temperature, compensation therefor is accomplished by a temperature-induced displacement of the central portion of the bi-metallic disc, and hence also the shaft, in a direction opposite to that caused by the change in the gas pressure resulting from that same change in temperature.

Telephone line extender with test thru capability

Abstract: A line, or loop, extender for a telephone system which is intended for connection in the tip and ring lines of a remotely located telephone set thereby to increase the line current to a level capable of more reliable operation of relays and the like in the central office switching equipment. A diversion relay is provided having contacts interposed between the line extender and the lines so connected that when the relay is in a first state the line extender is connected in series with the lines and so that when the relay is in its opposite state corresponding lines are connected together to form a metallic by-pass around the line extender completely isolated from the latter to establish a standard condition for the making of tests upon the lines. In the preferred embodiment the bridging relay is caused to be in its normal state during ringing to provide a ''''metallic'''' i.e., directly connected ringing circuit. A current detecting relay in the subscriber''s lines is connected to the diversion relay so that when the receiver is raised at the subscriber''s telephone set the line extender is connected into the circuit to raise the current to a reliable level. For purposes of isolation the current detecting relay preferably consists of a light-emitting diode plus photocell.

Simultaneous call telephone equipment test system

Abstract: An automatic dialing test system is disclosed wherein electrical signals such as pulses or tones representing each of the digits of a call number are applied to a selected group of communication lines of a telephone system. The digits to be applied to each line are selected on a diode plug board program field. The manner of signaling, dial pulse or multi-frequency tone is selected by an enabling switch that connects the multi-frequency applying relays and a diode decoder or, a dial pulse applying relay and associated diode decoder, to the program field. The duration of the pulses is determined by pulse generators driven from a common clock source.

Iso-phase navigation system

Abstract: An Omega navigation system is disclosed which includes a relay station at a fixed location. The relay station includes a receiver for receiving the signals being braodcast by the Omega transmitting stations and an arrangement for determining the phases of the signals thus received. The relay station also includes a transmitter for broadcasting a signal indicative of the phase of the signals as received at the relay station. The mobile station in the system is provided with a first receiver for receiving the signals broadcast by the Omega transmitting stations, in a conventional manner, and a second receiver for receiving the signals broadcast by the relay station. The mobile station also includes means for determining the phase of the signals received by its first receiver relative to the phase of the signals received by its second receiver, and thereby determine its position relative to the Omega transmitting stations, independent of its distance from the relay station.

Distance relay system

Abstract: A back up protective relay system using a distance relay for protecting transmission lines from faults occurring thereon which system responds only to unsymmetrical faults that give rise to negative-sequence current, is provided. As the polarity voltage is used a voltage relevant to the faulted phase.

Electrical control apparatus for an engine and variable transmission apparatus

Abstract: A dual marine gear installation includes three remote controls, one of which is a master control. Each control has control levers for positioning signal potentiometers providing input control signals to an engine governor throttle actuator and to a valve of a hydraulically actuated variable clutch. Each clutch lever also actuates a forward drive switch, a reverse drive switch and a brake release switch. A transistor diode logic circuit is connected to the forward and reverse drive switches and includes a selected control relay for each control and a transfer relay. A main selection switch only at the master control selectively energizes one of the control relays to condition the circuit for transfer of control. The transfer relay is controlled by the energization of the control relays and by the logic circuit to permit transfer only if the next selected control is in the same drive condition as the controlling station or in neutral. The master control includes the start switches and must initially be in control with the clutch lever in neutral to start the engines. Operation can be transferred to a different control only at the master control but the master can retake control at any time subject to limitation of the setting of the clutch levers.

Reflective relay optics for use in laser deflection systems.

Abstract: The optical coupling between the two axes of a light beam deflector may be conviently accomplished by using a reflective relay optical system. Such a system is generally less lossy, less costly, and easier to align than its refractive counterpart. The principal disadvantage is that since it is necessary to operate the relay off-axis, there is an interaction introduced between the otherwise orthogonal scan axes. This interaction may be eliminated electronically, however, by applying an appropriate coupling network between the deflection amplifiers. A breadboard prototype of such a reflective relay system has been operated and found to be capable of resolution of greater than 1000 resolvable elements per axis (with 2-mm aperture) and accuracy of greater than 0.5%.

Vehicle seat belt alarm and starter interlock control system

Abstract: A source of voltage is connected to a starter interlock through a normally open seat switch and a first normally closed seat belt actuated switch. Closing of the seat switch when a passenger sits connects the voltage to the interlock and disables the starter mechanism. Buckling the seat belt opens the seat belt actuated switch and enables the starter mechanism. The voltage is also connected to the starter interlock through the series combination of the normally opened seat switch and a normally closed relay switch. Battery voltage is coupled to the relay switch coil through a second normally open seat belt actuated switch and a capacitor in series. Buckling of the seat belt causes a pulse of current to be transmitted through the capacitor to energize the relay coil thereby opening the normally closed relay switch. A holding circuit through the seat switch maintains the relay switch open. Thus, the seat belt must be buckled after sitting down in order to provide the pulse of current to initially close the relay switch and to provide the continuing current to keep the relay closed. While the vehicle is in use, a warning buzzer and warning light are actuated by the same voltage source which disables the starting circuit.

Interrelated shift, starter and clutch controls

Abstract: A marine engine is coupled to a propeller by a clutch unit and a shift unit. A d.c. permanent magnet motor is coupled to the shift unit and the clutch unit. The motor is energized in a servo loop to selectively establish a forward drive, a reverse drive, or a neutral shift position. The motor is connected to the power supply through a pair of relays to ground both sides and to selectively connect one side to the power supply. A forward relay line is opened by a motor operated cam switch responsive to a full shift position. The reverse relay line is similarly controlled. A neutral line is connected to both of the cam switches and includes a similar cam switch which is actuated in the neutral position. A three-position selection switch connects power to the several relay lines and the neutral line. An electronic interlock circuit interconnects the neutral line to the forward and reverse relay lines.

Time delay headlamp control system

Abstract: A vehicle headlights control system operative to illuminate the headlamps for a preselected period of time after the headlight switch has been opened The circuit control system is manually operated to energize a switch assembly illustrated in the form of a relay, the relay having a set of contacts associated therewith to interconnect the headlights with a source of electrical energy until such time as the relay is de-energized A timing circuit is provided which, when timed out, will cause the relay to de-energize and disconnect the headlights from the source of electrical energy The system further includes a door switch assembly which senses the condition of the headlight switch or running light switch being closed when the operator opens the door of the vehicle An audio or visual signal is provided to indicate this condition

Electromagnetic relay operation monitor

Abstract: A monitoring circuit is disclosed that is connected to the driving conductor to the relay by a transformer having one winding in series with the drive line from a fast operating, electronic, common control sequencing circuit. The monitor circuit includes a transistor, connected to another winding of the transformer and normally biased to be nonconductive. The transistor is brought into its conductive state by the dip in the operating current flowing in the drive conductor as sensed by the transistor to set a bistable device to record the operation of the relay.

Line lockout circuit

Abstract: A lockout circuit for connection in a telephone switching exchange utilizes a lockout relay to isolate a telephone line from common switching equipment in the exchange whenever a telephone receiver and/or the connected telephone line form a closed loop path and no attempt is made to complete a call within a prescribed period. Removal of the ground connection to the sleeve lead by the conventional timer in the trunk circuit energizes an operate winding of the lockout relay. The relay also has a hold winding connected through a set of its own contacts and the subscriber''s line, and remains held up so long as the line loop remains closed.