Showing papers on "Relay published in 1972"

Burglar alarm actuated by cut telephone wire

Abstract: A burglar alarm which is actuateable by the cutting of a telephone set wire such as located outside of a residence home, the alarm relay switch-actuating circuit being connected to either battery or DC-rectified AC-power source, the detector and actuating circuitry of a preferred embodiment including positive and negative leads connectable to telephone wire contacts of corresponding polarity, each lead including adjacent to the respective contacts, in series, a resistor, the respective resistors being connected to different terminals of each of a third resistor, a capacitor, a zener diode, and a field effect transistor (FET), the negative lead being connected to the FET gate terminal and to the diode such that electrons are flowable solely from said negative lead to said positive lead, and said postive lead being connected to each of the FET source and to a base of typically an NPN transistor, the FET drain being connected in series through a fourth resistor and a relay switch coil to the NPN collector, the relay switch being actuateably closeable of an alarm power circuit, the NPN emitter being connected to one terminal of a second capacitor and to a DC power source terminal of the relay alarm switch-actuating circuit, and the remaining relay switch being connected to each of the remaining terminal of the second capacitor and the remaining coil lead to the relay switch, the relay alarm switch-actuating circuit preferably including, in series, the relay actuating coil, the NPN transistor, a step-down transformer coil, and a rectifier diode permitting DC current to flow toward each of said collector and said drain.

Thermostat chatter protection for refrigeration compressor motors

Abstract: The motor of a reciprocating refrigeration compressor is provided with a motor control and protection system, which includes means for preventing the contacts of the motor relay from welding or otherwise being damaged by vibration of the system thermostat. The motor relay is energized or de-energized by a solid state switch, which is controlled by two or more trip circuits in response to a condition of operation of the system. A current sensor provides a signal proportional to motor current which is summed with an opposite polarity reset signal and integrated to provide a signal to a first trip circuit. The room thermostat contacts close in response to a demand for refrigeration and provide a current through the switch means to energize the relay. When the thermostat contacts stay open for a short period of time, the open circuit voltage across them is integrated and eventually trips a second trip circuit which actuates the switch means to a nonconducting condition, thereby de-energizing the relay and preventing damage to the relay contacts. A feedback circuit raises the output of the integration circuit and decreases the trip threshold of the first trip circuit to trip the first trip circuit, whereby a period of time must elapse while the reset signal is integrated to the reset level before the relay contacts can be closed again. If the contact chatter lasts only a very short time, the signal due to integrating the voltage across them will not be sufficient to cause an unnecessary trip.

Apparatus for protecting and testing telephone networks

Abstract: One of the two lines (e.g. tip and ring) linking a telephone company network with a network owned and serviced by a customer of the telephone company is connected through a Zener diode with a relay, which controls two normally-closed switches disposed in the two linking lines. During normal operations the signals in the associated linking line are not great enough to trigger the diode, which maintains the relay deenergized. If a fault develops in one of the networks, an operator at a remote central station of the phone company momentarily applies a high voltage through the associated linking line to the diode, which conducts and momentarily energizes the relay to open its switches and isolate the networks from one another. An RC circuit in parallel with the relay holds it energized for a short time after the triggering signal disappears to enable the operator to test the phone network for faults. Also the two linking lines are provided with current, voltage and power overload devices to prevent customer-owned equipment from damaging the company's network.

Dual battery charger for vehicles

Abstract: A dual battery charger system for vehicles, such as a system for charging an automobile main battery and an auxiliary battery for a camper, a mobile home, a motor home or boat, in which the system has an ignition coil and a unit having a lead connected to the main battery, a lead connected to the auxiliary battery, a switch interconnecting the leads, and a relay coil for closing the switch. Leads interconnect the main battery lead to the relay, and a transistor is disposed in at least one of the two relay leads, the base of which is connected to the ignition coil to sense the operation of the engine and thereby control the current to the relay coil and the current to the auxiliary battery. The system can use a weak sensing signal to control the relay and will respond instantaneously to any condition which would be a drain from the main battery to the auxiliary battery.

Ac power changeover

Abstract: A power changeover circuit for selectively connecting an electrical load to one of two available power sources, preferably alternating current sources, wherein one of the sources constitutes an engine driven generator requiring a predetermined time to reach specified output characteristics after energization. Relay operated changeover switch means selectively connects the load to either of the electrical power sources, and second switch means in series with the changeover switch located between the changeover switch and the engine driven power source delays connected of the generator source with the load after disconnection of the load from the other source until the generator output reaches specified characteristics. Further, the circuit provides for the disconnection of the load from the generator upon deenergization of the generator, and prior to the changeover switch connecting the load to the other supply source in order to prevent arcing. Relays, resistors and time delay switch devices are utilized in the circuit to provide the desired operation.

Zero voltage switching photon coupled relay

Abstract: A solid state relay or controlled switch which may be utilized in place of an electromechanical relay to conduct AC power from a source to a load The solid state relay includes a load current carrying portion and a control portion which has complete and permanent electrical isolation from the load current carrying portion The load current carrying portion is controlled exclusively by photon coupling between a photon generator in the control portion and a photon-activated element in the load current carrying portion A variable impedance device affects the photon switching sensitivity of the photon-activated element and provides the logic necessary for switching at essentially a zero voltage

Bi-static circularly symmetric retrodirective antenna

Abstract: A circularly symmetric antenna system capable of providing retro-directive retransmission of a modulated or an encoded incident signal, or having the ability of being employed as a bistatic relay where retransmission may be directed from the initiating station. Also the system may be used to provide selective automatic suppression of a retransmission in an unwanted direction.

Portable defibrillators including rotary solenoid relays for energy transfer and dumping

Abstract: A portable defibrillator including at least one open-frame relay is disclosed. The relay combines the functions of previously-used transfer, dump, and ECG protection relays required in portable defibrillator-ECG monitor units. The relay includes at least one rotary solenoid for providing reliable operation while yet resisting accidental operation due to physical shock or the like.

Circuit for suppression of spurious pulses resulting from relay operation

Abstract: Pulses are generated by connecting the closure of a reed relay switch across a charged capacitor in an RC network. The pulses are then inverted and coupled into the ''''CLOCK'''' input of a ''''D'''' type flip-flop circuit.

Telephone line card system

Abstract: A telephone line card circuit including electrical devices and circuitry for minimizing the electrical components by providing an optical detector for controlling the input to an integrated circuit which in turn controls a multiple function relay operable as a line holding device and a visual and audible signal control device. This circuitry is particularly adapted for use in a key telephone system wherein a plurality of telephone sets are adapted to be selectively connected by an appropriate line key conventionally associated with a hand set, and this line card system includes a delay circuit to preclude dropout of a hold circuit due to line transients or line reversals. When a particular phone is connected to a particular telephone line through a key line button, provision is made for detecting this condition by another integrated circuit which controls a second relay operable for the control of a multiplicity of functions, such as controlling a visual signal for indicating that the circuit is in use, for controlling a line holding bridge, and for controlling the state of the first relay.

Repeater fault localization system

Abstract: A repeater fault localization system for line repeaters which are distributed in attelecommunication network and are fed by a remote supply source which is arranged in the initial station. This station includes a transmitter for feedback command signals, which transmitter consists of an inverter for the remote supply voltage and in which a receiver for feedback command signals is arranged in each amplifier, which receiver consists of a relay for feeding back the line repeaters, the relay being connected to a store which is excited when the voltage pulses are applied with the reversed polarity to the line repeaters in order that contacts of the relay switch off the supply line behind a fedback line repeater. Use: localization of faulty line repeaters.

Television communication system with time delay compensation

Abstract: A television station which receives remotely originated signals via relay satellite can time its local sync and burst signal generators with a standard reference frequency which it itself sends to the relay satellite and receives back from the relay satellite. This permits locally originated signals timed by the local sync and burst signal generators to be synchronized with the remotely originated signals to good approximation, despite time delay variations of the remotely originated signals caused by variations of the relay satellite orbit, permitting an adjustable delay line to then be used to compensate remnant delay variations. Consequently, cross fading or other special-effects mixing between locally and remotely originated programs is facilitated.

Mechanical transmission relay for a control facility comprising a manual element and a servo-motor, and its use in aircraft control systems

Abstract: A relay, incorporated in a single box, and including a single torsion spring which provides a reaction force equal and opposite to forces applied to the relay so that play between the parts is eliminated. The relay is used in an aircraft control system, being connected by a link with a manual control element and a servo-motor. The servo-motor coacts with the relay and actuates a control surface of the aircraft. The relay includes a pivotable connecting link fixed to a pivot pin. The pivot pin is connected, through a quadrant which meshes with a pinion gear, to a shaft. The shaft carries a disc at one end. Movement of the shaft may be restricted by an electro-magnetic brake. The relay reacts to movement of either the manual control element or the central surface so as to provide a feel force for the pilot of the aircraft.

Control circuit for cooling fans

Abstract: A control circuit for an electrically driven cooling fan has a relay for switching the fan in and out. Associated with the relay is resistance means for reducing the differential between the on and off points of the fan.

Remote control switch circuit

Abstract: A remote control switch circuit for switching on and off an associated load with a remote control relay operated by one of a plurality of remote control switches which is actuated independently of others. The circuit comprises a series circuit of a remote load section including the remote control relay connected to the load and normally closed and normally opened contacts connected in series through a pair of reversely connected diodes to the relay and a first operating switch section including the remote control switch for initiating and interrupting current fed to a polar relay and normally closed and normally opened contacts connected in series through a pair of reversly connected diodes to the switch, and an AC source providing source voltage to said series circuit. Other operating switch section or sections will be connected to said first section in parallel relation thereto.

Telephone subscriber line terminating test circuit

Abstract: A telephone line terminating test circuit for simulating a subscriber line subset to provide a properly timed off-hook signal responsive to a ringing current applied to the line. During precutover testing of a telephone switching system, the test circuit connects a subset simulating resistance across the line under control of a thermal relay operated responsive to the ringing current to simulate an off-hook state. The thermal relay is delayed in both its operate and restore phases to provide proper testing periods.

Arcing time relay

Abstract: An arcing time relay is provided for vacuum circuit breakers, and measures the length of time that arcing occurs after the circuit breaker contacts are open, or measures the time that excessive leakage current flows while the contacts are open, and provides an output signal if arcing time or leakage current exceeds given bounds which indicate improper vacuum conditions.

Numerically controlled machine tool with miscellaneous function control circuit to reduced unproductive periods to a minimum

Abstract: A numerically controlled machine tool is provided with a miscellaneous function control circuit which comprises a first relay circuit for starting miscellaneous functions when the operation of a feed device is completed, a second relay circuit for starting miscellaneous functions instantaneously when the feed operation is started, a command circuit for operating either the first or the second relay circuit in accordance with programmed information, and a control circuit operated by the first and second relay circuit for controlling a series of operation cycles of the miscellaneous functions, whereby the starting time of each of the miscellaneous functions can be selected in accordance with the programmed information coded on a record such as a punched tape.

Phase protection system for ac power lines

Abstract: A phase protection system is provided for protecting phase sensitive loads from being or remaining connected to AC power lines whenever a phase reversal occurs It comprises a solid state phase detection circuit, a DC power relay circuit, an AC-to-DC converter for energizing the relay circuit, and a bi-stable 4-terminal transducer coupled between the phase detection circuit and the power relay circuit, for controlling both circuits

Relay circuit for motor control

Abstract: In order to precisely position a machine driven by a rotating prime mover, the prime mover (electric motor) is electrically reversed to bring it to a stop. A zero speed switch, mounted on the motor shaft, senses when the shaft comes to a stop and at that time deenergizes a relay to open a pair of contacts in series with the motor contactor to stop the motor. The switch also opens the circuit to the winding of a slow-acting relay which, after a time delay, closes a pair of contacts connected in parallel with the previously-mentioned contacts, to prepare the motor for the next operation.

Electrical safety control circuit for punch presses and the like

Abstract: A safety control circuit for punch presses and the like has two push buttons which must be pressed almost simultaneously, each push button permitting discharge of a capacitor through a relay coil, each relay having a normally closed switch connecting the capacitor to a electrical supply and a normally open switch which, when closed, can bypass the normally closed switch of the other relay. The circuit can be arranged to fail safe.

Filtering applications in static distance relays

Abstract: A brief survey of past and present impedance relays is given, with particular reference to their immunity from interference owing to non-power-frequency components in their input signals. The frequency characteristic of a suitable digital filter is chosen on the basis of a spectral analysis of a 10 ms section of typical fault waveforms. The chosen filter is used in conjunction with a sampling system of measurement to realise a quadrilateral impedance characteristic. Results of an off line simulation of fault conditions are presented, in the form of typical fault waveforms at the relay input, and the relay operating time for various angles of fault incidence.

Relay center for remote control wiring system

Abstract: A relay center is provided for control with lower voltage control circuits of higher voltage power supply circuits. The relay center has a two level partition detachably mounted in a dimensionally conforming metal box. The first or rear level of the partition serves to position and retain relays extending through the partition between a high voltage and a low voltage side. The second or upper level is equipped with a terminal bar permitting highly visible, easily accessible, low voltage wiring of the relays.

Relay with time delay coil

Abstract: An electromagnetically operated A.C. relay which is actuated an adjustable timed interval after the relay is energized. The relay incorporates the timing accuracy provided by a solid state timing circuit and the power switching advantages provided by mechanically operated switching contacts. The relay includes a unitary coil and timing unit which may be substituted for a coil in an instantaneous operated relay to convert the instantaneous operated relay to a relay which is actuated a predetermined time interval after the relay is energized.

Two relay control circuit for automotive vehicles

Abstract: A circuit for enabling the accessories, starter solenoid, ignition circuit and gauges of an automotive vehicle includes an ignition switch with its movable contact connected to ground through a key and two output conductors, each in series with a relay, which are selectively energized, singly or together, according to the switch position. A switching network containing several switches, each operated by one of the relays, is arranged so that the low power accessories are energized when the switch is in the off position and one relay is energized, the starter solenoid ignition circuit and the gauges are energized when the switch is in the start position and both relays are energized, and all the utilization circuits are enabled when the switch is in the on position and the second relay is energized. An auxiliary circuit provides for horn operation and audible warnings when the vehicle lights are on or the key is inserted in the ignition switch when a vehicle door is open.

Timing control circuit for solid state protective relays for providing novel control of the pickup and timing circuits provided therein

Abstract: A static relay having sensing, reference, pickup and timing circuits and comprising a novel timing control circuit. The pickup circuit functions to initiate operation of the timing circuit when a predetermined threshold level of overload conditions exist. The novel timing control circuit functions to prevent the timing circuit from being reset due to momentary dips below the aforesaid threshold level while providing means for rapid reset of the timing control circuit when the input being monitored remains below the threshold.

Switchhook status signaling arrangement

Abstract: An electronic key telephone system is disclosed in which both conventional telephone sets as well as electronic key telephone sets are served. The electronic telephone sets transmit call signaling to and receive ringing control information from a main controller over a data link independent of the speech path but the conventional telephone sets must both transmit dial pulses and receive ringing signals over the talking path. A line transformer relay is used with both sets to repeat supervision. The conventional ringing signal, however, causes the line transformer relay to generate an erroneous switchhook state signal. In order to compensate for this erroneous response without requiring the reprogramming of the main controller each time the number of conventional and electronic key telephone sets served by the system is changed, a logic circuit inhibits the return of the station''s switchhook state ascertained by the line transformer relay for a predetermined interval after each cycle of ringing and causes an on-hook signal to be returned. When ringing is tripped, the same supervision logic in the interface circuit inhibits the return of switchhook state information ascertained by the line transformer relay for an interval longer than the maximum loop-open interval that can occur during normal dialing and instead causes an off-hook signal to be returned.

Scanner with reed relays

Abstract: Electrical switching apparatus such as a scanner comprises a plurality of reed relays, each of which has an operating coil, and at least one reed contact unit which is mounted outside the coil, to reduce thermal E.M.F. generation. The reed contact units are mounted on a first printed circuit board, and control respective analogue signals passing through the printed circuit tracks of this first board, while the coils are mounted on, and respectively energised via the printed circuit tracks of, a second printed circuit board parallel to the first board. In this way, interference between the scanned analogue signals and the relay energising signals is reduced.

Bipolar multiplexing circuit for telephone line selection

Abstract: A telephone is selectively connectable with any one of a plurality of central office lines through tree-connected relay circuits located in a remote control box Line selection switches located at the telephone operate the relay circuits over control leads, each lead being adapted for two functions by a pair of branch circuits with rectifiers connected to the lead at each end

Multivibrator for static relays having linear time dial

Abstract: A static relay utilizing an R-C network to provide a time current characteristic wherein inverse time-relationship is obtained for appropriately controlling tripping or other protective operations in power transmission and distribution networks. A multivibrator clamp circuit is employed in the static relay to control the time delay characteristic over a large range of values without altering the time delay wave shape and further incorporates a linear time dial setting to facilitate adjustment and usage of the static relay.