Showing papers on "Relay published in 1987"

Security control system

Abstract: A security and control system for use in a home or building which utilizes a coded audio link between the entry detectors/transmitters and the relay modules, and a digital pulse coded power line communication ("PLC") link between the relay modules and the system controller as well as between the system controller and the various remotely located slave units which control the energization of lamps, appliances, and alarms. The relay modules and controller include constant false alarm rate ("CFAR") receivers for isolating the coded audio signal from background noise and unique exclusion circuitry for decoding the isolated signal. The PLC messages are generated by impressing a pulse code modulated high frequency carrier signal onto the AC line at selected points in the AC waveform. The location of each carrier frequency pulse relative to the 60 Hz AC line cycle determines the digital value of the pulse. Both before and during a PLC message transmission, the controller and relay modules are adapted to check the status of the AC power line for the presence of intelligence or excessive noise levels and delay transmission if either condition is detected. In the security mode, the system has three major states: INSTANT-ARM, ARM-DELAY, and DISARM. In the INSTANT-ARM state, the system responds immediately to the detection of an intrusion event. In the ARM-DELAY state, a 40-second delay is implemented before alarm action is taken to permit an authorized entrant to DISARM the system. Significantly, the 40-second delay is implemented by each of the remotely located slave modules so that destruction of the controller by an intruder within the 40-second period will not defeat the system.

Cellular alarm backup system

Abstract: A cellular backup system is provided for a standard security alarm network, so that upon the inoperativeness of the telephone land line, automatic switch over to the cellular system is achieved, so that a digital communicator or telephone tape dialer may still transmit its distress call to a central alarm station, via the cellular system. A line fault monitor is provided which automatically detects the outage of the land-based telephone system which, in turn, provides an output signal to a latching relay which causes the activation of a pair of switching relays to automatically switch the connection of the alarm communicator from the DB-8 cord of the land-based system to a cellular interface coupled to a conventional cellular transceiver of a cellular system. The switching relays are latched in the state connecting the alarm communicator to the cellular backup system and held in such a state, regardless of the state of the land-based system, as long as a manual rest switch has not been used. The pair of switching relays are also used for coupling a standard land telephone handset also to the cellular system upon the outage of the land-based lines.

Multiple time delay power controller apparatus with time delay turn-on and turn-off

Abstract: Multi-time delay power controller apparatus for providing time delayed power-up and power-down for associated electrical equipment, such as computer systems, comprises a power stage configured for connecting to a conventional power outlet, a D.C. power supply connected to an internal D.C. voltage bus, an output stage having a plurality of time delayed outputs and a plurality of time delay turn-on timing stages connected in electrical series with one another between the D.C. bus and ground. Each such stage comprises an R-C circuit and a type 555 integrated circuit which together function as a timer. Included in each stage is a control relay. The energizing coils of the relays in odd numbered stages are connected to ground and of even numbered stages to the D.C. bus. The timing stages are connected so that the timing out of one stage starts the timing of the next-in-sequence stage, the timing of the first-in-sequence stage being started when the apparatus is turned on. The control relays, which provide voltage to the time delayed output stages are energized, in sequence, when each stage times out. Timed delay turn-off means are provided for sequentially removing the voltages to the outputs in the reverse order in which voltage is applied by operation of the control relays. The time delay turn-off means include relays through which the time delay turn-on relays are energized and which cause deenergizing of the control relays in the turn-off sequence.

Relay multiplexing for circuit testers

Abstract: Relay multiplexer circuitry for making a limited number of test channels connectable to a large number of test pins through relays connected to selected test channel nodes and test pin nodes, each test pin node being connectable to a unique combination of test channel nodes within a group of pin nodes, channel nodes and relays.

Current sensing relay circuit with adjustable sensitivity and tracking test circuit

Abstract: Ground fault interrupting circuit breaker (10) includes a sensing coil (20) which is the secondary winding of a current transformer having a core (18) and includes a test coil (22) also wound about the core with load conductors passing through the core. A current sensing circuit (30) compares the output from the sensing coil to a reference voltage which is adjustable to set the sensitivity of the breaker. A test circuit (42) generates in the test coil a test current whch has its magnitude determined by the same reference voltage which determines the sensitivity of the breaker, thus causing the test current to automatically track the sensitivity of the breaker without separate adjustment.

Secure communication system

Abstract: A secure communication system uses narrow beam laser transmissions from a relay station high above the surface of the earth and another station which may be a submerged submarine. Position reporting by a laser transmission from the other station or submarine to the relay station provides for acquisition, tracking and data transmission between the stations. For strategic use transmissions to the submarine for one way data transmission is achieved by radio relay to the relay station and laser down link transmission to the submarine. Transponding mode operation is provided for a two-way transmission data link.

Relay control apparatus

Abstract: The operation of an electromechanical relay is synchronized with the power line waveform where an electrical power supply is supplied from a source to an electrical load. The current voltage supplied to the load is characterized by a power line waveform. An electromechanical relay is positioned between the power supply and the load where contacts of the relay are opened and closed to interrupt and supply power to the load. A microcontroller is positioned between a power source and the electromechanical relay and actuates the relay so that when the contacts are closed or opened the contacts are not exposed to an undesired voltage. A feedback control circuit senses the opening and closure of the contacts so that in the event the contacts, for example close at an undesireable point on the load current waveform the microcontroller adjusts for the necessary delay to cause the actuation of the relay to occur such that the contact closure is at the desired point in the load current waveform.

Low power, leakage current switching circuit

Abstract: A low power switching circuit for delivering electrical power to a load includes a rectifier network connected between the hot leg of the AC utility supply and the earth ground of the utility supply. A neon lamp interposed in the rectifier supply limits the current drawn through the rectifier to less than the 500 μa code limit for current flow to ground. A high sensitivity, dual coil, bistable relay is connected between the hot leg of the AC supply and the load, which is connected to the neutral leg of the same supply. A capacitor network is connected to the DC output of the rectifier to store sufficient power to operate the relay, and a transistor switching network is connected to deliver the power from the capacitor network to the relay upon receipt of a trigger signal. A "smart" switch such as an area occupancy sensor may be connected to the transistor switching network to provide the trigger signal to cause the relay to switch AC power to the load.

Switch utilizing solid-state relay

Abstract: A solid-state relay is combined with a control circuit to form a switch which is bilateral and linear through the origin, can withstand large current or voltage surges, and can be toggled either electrically or optically. The relay portion comprises either a pair of or two subsets of DMOS transistors, and the pair of transistors or selected ones of each subset cooperate to form a pair of oppositely poled thyristors. The control circuit provides well regulated turn-on and turn-off of the relay and provides good immunity against high voltage transients on the switch's main terminals. The control circuit also serves to limit the maximum voltage that is applied to the gate oxides of the transistors.

Reclosing relay with nonvolatile memory of operations

Abstract: A reclosing relay for use in an electrical power system with a circuit breaker for clearing line faults by tripping and reclosing. The breaker has auxiliary contacts defining the state of the circuit breaker as open or closed. The reclosing relay includes a circuit responsive to the auxiliary contacts for producing a first signal representative of the state of the breaker and another circuit for generating a second signal when a loss of power to the reclosing relay is anticipated. The reclosing relay further includes an electronic circuit connected to the first signal producing circuit and the second signal generating circuit for supplying a reclose command for the breaker when the breaker is open by executing one or more operations in a predetermined reclosing sequence, for storing information in response to the second signal identifying which operation in the reclosing sequence is currently being executed, and for using the stored information to continue from the identified operation in the reclosing sequence upon restoration of power. Other features of reclosing relays and methods of operating them are also disclosed.

Shock protective circuit with electrical latch for small appliances

Abstract: An immersion detection current interrupter circuit with an electric latch for use in small electrical appliances. A sensor wire is positioned within an appliance to sense current leakage when in contact with a conductive fluid. A relay or solenoid connected to the sensor is positioned between the load leads in a latch circuit. When the sensor detects a leakage current, it causes a two-pole double-throw relay to latch, breaking the load lines beyond the relay. The relay will remain latched until the power cord is unplugged or reset by a switch which opens and closes the power lines. Once the component has latched, the maximum leakage current will be limited by the voltage drop across a diode.

Seismic signal transmission system using relay radios

Abstract: A system is provided for radio transmission between a central control and recording laboratory and spaced apart acquisition boxes in which relay transmission units are used for communicating with boxes which are directly inaccessible. It includes a centralization unit adapted for managing the exchanges of orders or data from the central laboratory with directly accessible boxes by means of a radio link in a first frequency band (f2), on the one hand and with the relay units by means of a radio link in another frequency band (f1). These latter manage the radio links with the inaccessible boxes by means of radio links at a frequency (f3) distinct from (f2). The relay units and the centralization unit are programmed for automatically managing the links between the central laboratory and any one of the boxes, whether they are direct or indirect, and, on the other hand, for reserving a part of the interrogation time of each box for the transmission of service data indicative of their correct operation.

Protective relays and methods

Abstract: Protective relay for use in an electrical power system having electrical conductors which are energizable with an AC voltage. The protective relay includes a circuit for sensing the AC voltage to produce an AC output that has zero crossings and a time period between zero crossings, a circuit for supplying an electrical signal representing a preselected pickup value of volts-per-Hertz for the relay, and a circuit responsive to the AC output and to the electrical signal for generating an electrical level as a function of both the time period and the pickup value and for producing an output signal for the relay when the AC output exceeds the electrical level. In this way, the output signal is produced when a volts-per-Hertz value of the AC voltage exceeds the preselected pickup value of volts-per-Hertz for the relay. Other protective relay apparatus and methods are also disclosed.

Boost voltage power supply for vehicle control system

Abstract: Inductor coil (13) of a relay (12) used to supply battery power to a power load (11) of a vehicle engine control system (10) is also used to provide a substantially higher than battery voltage (V Batt ) boost voltage (V Boost ) for vehicle control apparatus (20). Microprocessor (21) generates a control signal (V in ) having a 10:1 duty cycle for control of current excitation of the coil (13) during an effective on logic state for the relay (12). During coil current interruptions during the on logic state, energy stored in the inductor (13) is utilized via a rectifier means (26 and 27) to provide the boost voltage. During the on relay state, a movable member (14) of the relay is maintained in its actuated position since current interruptions during the on state are shorter than the relaxation time required for the movable member to assume a nonactuated state. The relay coil generates boost voltage without requiring an additional substantial inductive reactance, and without waiting until the end of the effective on logic state.

Power supply associated with AC line relay switch

Abstract: A relay switch (SW) in an AC main line has a DC-powered amplifier (AMP) for applying amplifier control sensor signals to the control circuit of the relay switch. To provide DC power for the amplifier when the relay switch main controlled current conduction path is conductive, a current transformer primary winding (W1) is arranged in series with that path, and the voltage appearing across the secondary winding (W2) is rectified. To provide DC power for the amplifier when the relay switch main controlled current conduction path is non-conductive, an open-circuit voltage related to that appearing across the open-circuit non-conductive path is rectified. To permit the use of one rectifier (CR1) for developing DC power for the amplifier it is advantageous to apply the open-circuit voltage to the secondary winding of the current transformer through a DC-blocking capacitor (C2) with sufficient AC impedance to restrict AC flow across the open-circuit relay switch path.

Power proportioning controller for solid state relays

Abstract: An economical astable multivibrator circuit provides a variable frequency, variable duty cycle digital signal for controlling a solid-state relay to provide power proportioning. An optical isolator receives analog input signals and converts those signals into a variable resistance signal for altering the RC time constant of the charge/discharge timing circuit. The controller is capable of driving several solid-state relays simultaneously and includes a powerstat adjustment for manually adjusting the range of power delivered to a load.

Standby power supply

Abstract: A battery operated standby inverter power supply uses an electromechanical relay switching network to connect and disconnect line power between input and output terminals. An overcurrent relay pulser rapidly opens the switching system relay contacts upon transition to battery mode, and a breakover diode network accelerates field collapse in the relay coil attendant to reversion of the relay to its normally closed condition attendant to each battery to line transition. A fault detector establishes acceptable line voltage thresholds, the exceeding of either of which triggers operation from line to battery mode. These triggering thresholds are automatically pulled closer together during initial system startup. An overload detector senses the load current in line mode and prevents actuation to battery mode if the load connected to the power supply output exceeds the rated current value of the inverter. A wiring detector prevents initial power-up to line mode in the event that the house wiring has been miswired so as to interchange the house ground and the voltage return lines.

Electromechanical lamp switching

Abstract: An electromechanical switching device connects and disconnects a second lamp means from a first circuit powering a first lamp means upon alternate powerings of the first circuit. A mechanical device switches the switching means and an electrical circuit across the first circuit has a relay to control the mechanical device.

Wiper control apparatus

Abstract: A wiper control apparatus includes a main relay switch for passing the voltage received from a power supply to make the wiper control apparatus operable, an ignition switch for passing the voltage from the power supply to make the vehicle operable, and control means for controlling the ON/OFF operation of the main relay switch. The control means operates in response to the conductive state of the ignition switch to render the main relay switch conductive. After a predetermined time in response to a cut-off state of the ignition switch, the control means renders the main relay switch non-conductive. The predetermined time allows the wiper blade to move down to a predetermined park position of a windshield after the ignition switch is turned off.

System and method of adjusting the interstation delay in an information transmission system

Abstract: Method of adjusting the interstation delay in an information transmission system comprising a large number of relay stations arranged in cascade and utilizing in one transmission direction the TDMA method, and a system to which such a delay adjusting method is applied. This method of adjusting the interstation delay in an information transmission system utilizing the TDMA principle can be advantageously used when the system comprises a large number of relay stations in a cascade arrangement. An adjusting range is imposed on the delay to be allocated to the transmission of data in order to avoid information jumps which may provoke overlapping on reception of these data. The adjustment of the delay is effected by starting with the relay station nearest to the central station, then the following relay station etc., and ending with the adjustment of the terminal station involved.

Vehicle burglar-proof device

Abstract: PURPOSE:To prevent an engine from stopping after starting by operating a relay control output power circuit so as to enable the start of the engine when the electronic code of a key is coincident with a value stored in memory with the result of identification between the key and a switch section, and by sustaining the present condition by means of a holding circuit when the key is turned on. CONSTITUTION:When a key is inserted in a switch, contacts 9, 10 are connected, and a contact circuit 17 delivers a confirmation signal to a trigger circuit 14. Then, a CPU 13 transmits a code signal so as to allow a light emitting element 8 to issue an infrared signal which is received by a light receiving element 11 in a switch 2 and is identified with a code stored in memory. If the code is coincident with the stored value, a relay control output power circuit 22 is energized so as to turn on a main relay 32 and a starter relay 34. With this arrangement, power can be fed from a battery 31 to an engine control circuit 30 and a starter motor 33, and accordingly, the engine is started. After the key is set at a turn-on position, the condition is self-sustained, thereby it is possible to prevent an engine from stopping.

Fail safe gas valve drive circuit

Abstract: A fail safe drive circuit for enabling the relay which in turn opens the valve for supplying gas to a burner is disclosed and includes a pair of field effect transistors both of which must be operating properly to enable the relay. One transistor receives an enabling input from a rectifier circuit and will be enabled only if the alternating input signal is of sufficient magnitude and repetition rate. The other transistor is turned on and off by the alternating input signal and the gas valve will be turned on only when each of the transistors is operating in its intended mode. The circuit thus discriminates against false enabling signals such as a direct current signal, line voltage signal, a non-repetitive alternating current signal, or other spurious signal.

The Development and Application of Directional Comparison Protection for Series Compensated Transmission Systems

Abstract: A new high speed Directional Comparison protection relay for capacitor compensated lines is described. It is shown that the special filtering and signal processing techniques developed overcome many difficult protection problems encountered on such lines. The relay design has been performed using computer-aided design (CAD) techniques and recent work on its implementation using a 16-bit bipolar microcomputer has been initiated. The latter indicates that the relay is readily implemented using present generation hardware.

Radio telephone system with relay change during communication

Abstract: System comprising several fixed relays each acting as a radio transceiver and which are tuned to a first so-called beacon channel frequency and to a plurality of so-called traffic channel frequencies, and as an application unit linked directly to the switched public telephone network, and a plurality of mobile sets each including a control logic unit, an interface with the user, a radio transmitter and a first radio receiver which are driven by a frequency synthesizer, the said first receiver being provided in order to receive both data signals and phone signals, and a first field meter. Each mobile set further comprises a meter (18) of the electromagnetic field received and a second radio-receiver (1, 3) dedicated to the reception of the data signals transmitted by the relays on the beacon channels, whereas the first radio-receiver (1, 2) is tuned to a traffic channel during telephone communications. The control logic unit (17) is provided so that, when the mobile set is communicating telephonically, the second receiver (1, 3) scans the beacon channels of all the relays in order to determine a new relay exhibiting the greatest amplitude of the magnetic field and available traffic channels, as long as the amplitude of the magnetic field received by the first receiver (1, 2) is below a specified threshold, this provoking the procedure for identifying the mobile set, its inscription on the new relay, and the tuning of the first receiver and of the transmitter to a traffic channel of the new relay.

Circuit for driving a relay used in an AC circuit, with a protection against contact welding

Abstract: A circuit for driving a relay having at least two contacts and an excitation coil. An AC power source is connected to the contacts of the relay for applying a voltage of a prescribed frequency to these contacts. A detector section compares a pulse current, induced in phase with the AC current supplied from the AC power source, with a reference value, thereby producing a detection signal. In accordance with this detection signal, the positive and negative phases of a signal having a cycle longer than, and being asychronous with, said AC current, are delayed alternately or at random, thereby generating a timing control signal. This timing control signal closes and opens said relay at random timings, thereby protecting the relay from contact welding.

Heavy duty lamp flasher for trucks, trailers and the like

Abstract: A heavy duty lamp flasher for turn signals for trucks, trailers and the like including a switching relay having normally open and normally closed contacts and a moveable relay arm and relay coil, and an arc suppression circuit formed of a transistor or pair of transistors connected in parallel with the switching relay to minimize contact arcing and load carrying limitations. A diode and capacitor pair is connected to an integrated circuit oscillator for activating and deactivating the relay and another diode and capacitor pair is connected to the gate of the transistor and to the relay coil, such that the mechanical contacts of the relay, with their inherent mechanical delay, control the transistor circuitry so that the transistor provides the primary current path during movement of the arm between the normally closed and normally open contacts and the normally open contact provides the primary current path when it is closed.

Power source device

Abstract: PURPOSE:To reduce the occurrence of noise by employing a semiconductor joint part such as a thyrister through the use of a solid relay when a main electric route with a great current is opened and closed. CONSTITUTION:A current limit resistance 7A is connected to any one of the solid relays 2A-2C serially connected to respective power source lines, and any one of the remaining relays is made conductive. Then a space between a smoothing circuit and the current limit resistance 7A becomes a closed circuit through the solid relays 2A-2C and a rectifier 3, and a current is flowed to charge the smoothing capacitor 9 of the smoothing circuit. At that time, the nonconductive solid relays 2A-2C are made conductive to short-circuit the current limit resistance 7A, and a steady DC voltage is outputted to the smoothing circuit. Then power source modules 4A-4B becoming large loads are started to complete the activation of a power source device. For stopping the power source device, first the power source modules 4A-4B are stopped, and then all the solid relays 2A-2C are opened, thereby completing the stoppage.

Piezo-electric relay

Abstract: A piezoelectric relay requiring less piezoelectric material than conventional piezoelectric relays is disclosed. The relay differs from conventional relays in that the contacts are touching with essentially no force applied between the contacts when no power is applied to the relay.

Circuit arrangement for switching over connections in a communications device

Abstract: Modern communications devices increasingly exhibit different AF sources and sinks. To establish connections between these various AF sources and sinks, switch-over devices in the form of a relay or the like are in most cases used. To establish arbitrary connections between the various AF sources and synchs, two bus systems isolated from one another are provided in the communications device, the useful information, for example voice signals, being transmitted via one bus and the control signals being transmitted via the other bus. The various AF sources and synchs are connected by means of switchable amplifiers.