Showing papers on "Relay published in 1976"

Time variable thermostat

Abstract: The invention is a time variable set point thermostatic device adapted for use in a two-wire circuit of a heating or cooling system without additional wiring. Electric timer means interconnected with a thermostatic switch and starting relay means of a transformer having a primary and secondary winding periodically changes the set point of the thermostatic switch at selected intervals. The circuit is arranged to limit the current in the two-wire control circuit to a value less than that required to actuate the starting relay of the heating or cooling system in the two-wire control circuit with the thermostatic switch open and to actuate the starting relay when the thermostatic switch is closed when the ambient temperature to be regulated varies a determined amount from a selected temperature set point and the thermostatic switch is closed.

Contactor device including arc supression means

Abstract: An electrical contactor device includes a solid state arc suppression circuit connected in parallel with main relay contacts. Auxiliary contacts provide gating signals to the arc suppression circuit prior to, during and shortly after the main contacts open. Protection contacts connected in series with the arc suppression circuit are part of a relay which is actuated by additional auxiliary contacts of the main relay. The protection contacts prevent the arc suppression circuit from operating during initial closure of the main contacts thereby allowing the contactor device to be used in those applications where a high in-rush current is expected. A delay circuit holds the protection circuit relay contacts closed after the main relay contacts open to permit operation of the arc suppression circuit; the relay contacts thereafter open to isolate the arc suppression circuit and thereby to prevent any leakage current from flowing therethrough and to prevent any false triggering thereof. A fuse in the protection circuit prevents operation of the contactor device in the event the solid state devices become short circuited.

Engine malfunction protection

Abstract: A three-terminal module contains a relay with normally closed switch contacts and a delay circuit for the coil which opens the switch. The module switch contacts are wired between the engine ignition switch and the ignition coil of the engine. Malfunction detectors energize the delay, which eventually energizes the switch-operating coil, thereby stopping the engine. Opening and reclosing of the ignition switch enables the engine to restart.

Self-cut-off power switch for a remote controlled electronic equipment

Abstract: A make-type contact of a relay-type member and a manual switch are connected between a commerical A.C. power supply and a load circuit. The manual switch is turned on only when it is being manually actuated and turned off when it is not manually actuated. A winding of the relay is connected to the load circuit such that an excitation current flows therethroiugh through the load circuit or a control unit, and it is also connected to the control unit for receiving signals from a remote control unit. When the manual switch is turned on through manual actuation, a power is supplied to the load circuit or the control unit to excite the winding-type portion so that the make-type contact is closed to hold the power to the load circuit even after the turn-off of the manual switch. When the control unit, on the other hand receives the signal from the remote control unit the winding-type portion is deenergized to stop the supply of the power to the load circuit.

Dual oil filter automatic switching system

Abstract: A dual oil filter automatic switching system incorporating two oil filters and a switching oil valve and an oil pump, all connected together. The system also includes electric means incorporating a differential pressure switch and a latching relay, and an electric signal and an electrically-operative temperature switch are also disclosed. The oil valve is electrically responsive to the electric switching, and the valve directs the oil to either or both of the filters.

Ground fault protective device

Abstract: A self-powered self-contained ground fault protective device including a current monitor, an electronic circuit for amplifying the output of the current monitor, a relay connected to the amplifying circuit and adapted to operate whenever ground fault current through the current monitor rises above a predetermined level, and an interchangeable rating plug including means for activating a circuit board switch. The current monitor, amplifying circuit, and relay are all supported and enclosed by a molded insulating housing. The rating plug is inserted into a socket on the exterior of the housing.

A.c. relay system

Abstract: An A.C. relay system for making and breaking an A.C. power line utilizing an electromagnetic relay having a coil for opening and closing the mechanical switching contacts, a bilateral gated semiconductor such as a triac connected across the contacts, and a control circuit for switching the relay and triac in proper sequence is disclosed. The control circuit comprises a sequence control unit, a phase detector, a triac firing unit and a relay energizing unit. Upon actuation of the sequence control unit, the triac firing unit first fires the triac and then the relay energizing unit energizes the coil to close the mechanical contacts. To break the A.C. power line, the sequence control unit first de-energizes the relay energizing unit and then after a suitable time interval de-energizes the triac firing unit to cut off the gate signal, the triac being turned off when the load current on the power line is below a triac holding current.

Telephone isolation system

Abstract: The system disclosed transiently disconnects a subscriber's telephone equipment and network from the service provider (e.g. telephone company) network for a predetermined period of time in response to a remote switching pulse to facilitate the execution of diagnostic measurements without the necessity of visiting the subscriber's premises. The disconnect action is carried out by a two stage solid state circuit incorporating gate controlled devices such as SCRs together with RC networks whereby a capacitance is charged in response to the remotely originated switching pulse and then discharges to energize a switching relay and to maintain it energized for a predetermined period. In the energized state the switching relay isolates the subscriber network and its equipment from the telephone company network to permit the diagnostic measurements. The circuit design also provides improved noise suppression, as well as protection against spurious switching and certain overvoltage conditions. A modified version also provides means for detecting certain tip short conditions.

Engine idle control

Abstract: An automatic control for continuing idle operation of an internal combustion engine, particularly a diesel motor, to provide proper engine conditioning before the engine is shut down. Automatic control circuitry is added by connection to the contacts of a conventional manual control switch for the engine. Normally open contacts of a relay are pre-set during engine use to bypass the manual control switch for a predetermined time following subsequent opening of the switch. A first electronic detector monitors the closing of the switch, while a second electronic detector monitors its opening. The two detectors operate both the relay and an electronic timing mechanism. The timing mechanism opens the relay contacts following a predetermined period after the opening of the manual control switch. In this way shutdown of the engine is accomplished electronically as an automatic function following the manual opening of the usual key switch.

Remote-testing arrangement for PCM transmission system

Abstract: Two sets of line terminals in a pair of PCM head stations are interconnected by a set of transmission channels via a number of cascaded relay stations each including a line repeater for each channel. A service link extends from an address generator in one head station to a monitoring unit in each relay station, the monitoring unit including a regenerating circuit for throughgoing address codes and further including a discriminating network which, upon detecting an address code identifying that relay station, sends a sinusoidal priming signal to all the associated repeaters. A predetermined PCM test code, e.g. one containing a certain number of consecutive zeroes, is simultaneously transmitted from the same head station over the channel containing a selected repeater to be checked which, upon coincidence of the test code with the priming signal from the associated monitoring unit, closes a loop for feeding back the test code to the originating line terminal.

Automatic resetting temperature controlled battery changing system

Abstract: An automatically resetting battery charging circuit in which the temperature of the battery is sensed by a temperature responsive switch to control the charging of the battery between a fast charging rate and a trickle charging rate. Two current paths are provided between a charging current source and one terminal of the battery. The temperature responsive switch is located in one current path (the main or fast charging path) in series with a normally closed relay contact. The relay coil which controls the actuation of the relay and the opening of the relay contact is in the second current path (the trickle charging path) connected across the temperature responsive switch and the relay contact. When the battery temperature exceeds a predetermined value, the temperature responsive switch opens causing charging current to flow through the relay coil. The relay is thus energized, opening the relay contact and keeping the main charging path open irrespective of battery temperature. Thereafter, a trickle current is delivered to the battery through the relay coil. The relay coil is deenergized and the charging circuit automatically reset for subsequent charging by disconnecting the battery or otherwise interrupting current flow through the relay coil.

Safety control circuit

Abstract: A safety control circuit for an electrically operable machine such as a punch press is described The circuit includes input means for delivering electrical power to the machine and first and second relays, each including switching means and an associated relay coil for operating said switching means The switching means of the relays are connected in said input means so that electrical power is delivered to the machine only when both relay coils are energized First and second capacitors are associated respectively with said first and second relay coils and a source of direct current is provided for charging the capacitors The direct current source is connectable with both capacitors through said switching means of said relays when both relay coils are de-energized, so that the capacitors are both normally charged when the circuit is at rest First and second machine activating switch means are associated respectively with said first and second capacitors Each of said switch means is arranged, when operated, to connect the relevant one of said capacitors with the associated relay coil to cause the capacitor to discharge into the coil and operate the relay The circuit also includes resistor means connectable with either of said capacitors through the switching means of the relays, said switching means being arranged in the event that only one of said machine activating switch means is operated, to connect the capacitor associated with the other switch means to said resistor means, whereby, in use, the relevant capacitor will progressively discharge into the resistor means, preventing energization of the associated relay coil and hence activation of the machine after the level of charge in the capacitor has fallen below that required to energize the associated relay coil

Current supply cct. for electromagnetic elements - has series power transistor controlled by complementary transistor coupled via diode

Abstract: The current supply circuit for a relay and other inductive loads consists of a power transistor (T2) in series with the relay (1) across the supply poles. The power transistor is controlled by a second complementary transistor (T1) whose emitter is connected via a diode (D2) and capacitor (C) to the negative supply pole and whose base is also coupled over a Zener diode (Z1) to the negative supply pole. A diode (D3) connects the capacitor to the relay. The relay is shunted by a free-wheeling diode (D1) and the switching signal is applied to the second transistor base. The circuit rapidly operates the relay even at high-speed switching cycles.

Vital relay operating circuit

Abstract: There is disclosed a circuit for energizing a vital relay in response to an input signal that is modulated between two frequencies. A discriminator circuit responds to the modulated frequencies and alternately produces an output patented of one polarity and then a reverse polarity in response to the modulated signals. Coupled between the discriminator and the vital relay is a relay driver which responds to the output of the discriminator and energizes the vital relay. A d.c. power supply is coupled to the relay driver. The vital relay includes two windings. Failure of the modulation, the d.c. source or virtually any circuit element, will result in release of the vital relay. The disclosed embodiment uses photoresistors as switching elements.

Switching circuit for telecommunications lines

Abstract: A switching circuit includes a magnetically latching relay and associated contacts connected between a subscriber loop and associated subscriber equipment. In one state of latched operation the subscriber equipment is connected to the loop via the contacts and in the other state of latched operation the subscriber equipment is disconnected from the loop. To operate the relay a voltage is applied to the loop, the voltage being of sufficient value to charge a capacitor in the switching circuit to the threshold voltage of a PNPN diode which is connected in series with the operate coil in the latching relay. The PNPN diode discharges the capacitor through the operate coil to cause the relay to latch magnetically in a make or break state depending upon the polarity of the discharge current. An AC resonantly responsive relay is added to the switching circuit to selectively inhibit switching circuit response in the case where more than one switching circuit is utilized on a loop. Hence different subscriber equipments can be selectively connected or disconnected as required.

Group controlling system

Abstract: PURPOSE:By eliminating a high-tension controlling device composed of a relay circuit, a unit of programmable sequence controller is made to substitute it and further, make it applicable to a plurality of neumerical control machine tools.

Bi-directional signalling arrangement for telecommunications systems

Abstract: An arrangement for providing signalling to the lines of a telecommunications system employing non-metallic switching crosspoints such as a solid state switching network or time division switching network. In a system employing either type of network, line signalling such as ringing, coin control signalling, wire chief testing, and such other signals which are essentially high voltage signals cannot readily be transmitted through the switching network. The present system as disclosed provides an arrangement employing a common, multiplex highway between one or more signal sources and the line circuits. Operation of a switching element such as a relay in a line circuit selected by the common control completes a metallic path from the source bus to the selected line through closed contacts of the relay. In addition, signals of one or more different types may be multiplexed within a signal cycle to produce signals to a number of lines during the period when one line is being signalled. Within this framework, bi-directional signalling such as that required for testing lines can be readily implemented.

Solid state overload relay circuit

Abstract: A self-powered solid state overload relay circuit having current transformers energized by conductors supplying current to a multiphase alternating current motor. The transformers have secondary windings connected to charge a capacitor with a voltage indicative of the magnitude of the maximum current in the motor windings. The circuit includes presetable impedance circuits which permit the circuit to be easily programmed to respond to a range of abnormal motor currents in the winding in motors of varying size and service factor ratings, components which are arranged to duplicate the operation of melting alloy and bimetal type overload relays in an automatic or in a trip-free manual reset mode, a light emitting device which visually indicates when the relay is in a tripped state, and components which cause the relay to be insensitive to ambient temperature variations.

Solid state inverse overcurrent relay

Abstract: A solid state inverse overcurrent relay having a long slender wire connected to respond to a current which is proportional to the line current in a power system. An infrared detector or phototransistor is positioned to sense a predetermined color of radiation from the wire and is connected to fire a silicon controlled rectifier which is connected in series with a trip coil for a circuit breaker. The trip coil and silicon controlled rectifier are connected to an independent DC power source. The long slender wire on energization responds to the current which is proportional line current with the same time current characteristic as a fuse. In an alternate embodiment of the invention the relay is connected to the power system through a bridge rectifier which provides the DC current for operating both the heat responsive wire as well as the infrared detector.

Two wire command and monitoring system

Abstract: An improved system and method for transmitting and monitoring, for example, commands to relays or other output command devices driving controlled devices remotely located from the transmission portion of the transmission and monitoring system. The system is usually divided into two parts geographically separated by a significant distance with two wires running between the parts. The first part is used for transmitting the command and interrogation signals through the use of current levels set by overall circuit characteristics and produced on alternate positive and negative half cycles by an alternating current source and set by the resistive load in the loop. The second part is for interpreting the signal by relay discrimination to determine if it is a command or just the interrogation signal requesting the current state of the device being controlled by the system and also for local indication. During operation, when no commands are being sent to the receiving part, the signals indicate the present state of remote contacts that represent the positional state of the controlled device. When a command is to be sent to the receiving part, the current is changed by resistive load change to a new level which represents the command to be transmitted to the receiving part. The improvement prevents the stop command from actuating the system in an improved manner rather than stopping the controlled device.

Line conditioning and transfer circuit

Abstract: A circuit for electrically preconditioning a telephone line and switching an associated ringing generator on and off at the instant of opportune circuit conditions to eliminate circuit transients. The line circuit is switched by means of a relay so that an equipotential charge exists on either side of the switching contacts at closure and with zero current through the contacts at opening to eliminate suppression devices.

Dual operating control circuits for intrusion detection systems

Abstract: A series loop is in series with a control relay coil which has a first and a second contact. The first contact is coupled to an alarm and the second contact is coupled to one end of the loop. A control arm of the relay is operated by the coil to coact with said first contact when the coil is not energized and to coact with the second contact when the coil is energized to cause said second contact to latch said relay when the series loop is closed. Power is selectively applied to the control arm of the relay and a unidirectional current conducting circuit is coupled between the control arm of the relay and the second contact. The circuit supplies energizing current to the coil in the loop for the application of power to the control arm. This causes the relay to operate and therefore to latch if the loop is closed upon application of power to the control arm. The system user also is afforded a predetermined time to break the loop for purposes of leaving the premises and due to the nature of the unidirectional circuit, is assured that the intrusion system will be placed in a secured mode after the loop is broken.

Radiant energy integrating meter

Abstract: A radiant energy integrating meter having one or more parallel connected reversed biased radiant energy sensor cells connected to an integrating circuit having an integrating capacitor. A trigger circuit having a differential amplifier, connected to the integrating capacitor, which drives a further amplifier, is adapted to close a first switch such as a silicon controlled rectifier in response to a predetermined integrated sensor current. A counter circuit is coupled to the first switch and advances by one each time the first switch is closed. A second switch such as a relay is coupled to the first switch to provide a discharge path for the integrating capacitor. Finally, a delay circuit is coupled across the first switch to open the first switch after a predetermined time delay.

Fail-off photo control circuit for night lighting

Abstract: A circuit for controlling the energization of a night lighting load or the like, in which failure of the main circuit to control and shut off electrical supply to the load during daylight hours leads to permanent shutdown of the electrical supply to the load Two photosensitive elements are provided in the circuit One element, eg a photocell, is a main control which periodically operates a relay and supplies electricity to the load, ie at night The second element, eg a second photocell, is connected in the circuit, together with a second relay, in such a manner that failure of the first relay to operate and open the load circuit during daylight hours will cause the second relay to operate and permanently open the load circuit

Relay circuit with chattering make contact - has electronic contact operated by optical coupler in parallel with relay contact

Abstract: A winding in the circuit can be connected to a control d.c. voltage. An electronic contact is operated by at least one optical coupler (7). It is connected in parallel with the relay make contact. A light emitting diode (7) in the optical coupler lies in the relay control circuit. The electronic contact is conducting only at voltages above a specified threshold higher by an order of magnitude than the voltage across the current carrying contact. The apparatus has four terminals (1, 2, 3, 4). The photocell (72) in the optical couples is connected to the base of a Darlington pair (51).

Protective relay arrangements

Abstract: A starting relay for a power transmission line protection system. Where long line sections have to be protected, confusion can arise between normal heavy loads and distant faults having comparable line impedance. The invention provides a starting relay which limits operation of the normal distance relay to conditions within the starting relay characteristic, this being derived by phase and amplitude monitoring of the load at the relay station. The characteristic accepts heavier line currents at potentially normal phase angles than at abnormal phase angles. Certain unbalanced faults do however exhibit normal phase angles and these are detected by substantial line voltage drops. A described combination of phase, current and voltage detectors thus covers substantially all faults. The starting relay finds particular application in a carrier-blocking fault detection scheme employing duplicates of the basic characteristic.

Fluid pressure relay

Abstract: A primary element is connected to a control element of a fluid pressure relay to move the element to positions at which fluid pressure outputs of the relay will be generated to represent the positions.

Press valve checking circuit - has spindles of independent operating valves probed by proximity arrangement

Abstract: The circuit is used esp. to check the movement of press safety valves which have electro-magnetic pre control valves. The stroke of each valve-spindle is probed by an electrical proximity arrangement. The output signals of the proximity arrangements are fed to two independently operating bistable storage relays. The relays can be switched off by means of the control contacts of the relay, while the electro-magnets of the pre-control valves can be switched off by means of the load contacts of the relays. The storage relays can be connected to a supply source by means of a manually operated switch.

Telescopic car aerial with control pushbutton on receiver - has calibrated switch and memory for selected length of extension

Abstract: A telescopic aerial for a car radio receiver which is operated by means of an in-out switch on the receiver. The aerial can be extended to any length up to a maximum. The is also a memory which will extend the aerial to any desirable length after having been retracted. There is an additional calibrated switch which will determine the extended length. The storage unit comprises a forward and backward counter (31), a digital store (32) and a comparator (33). If feeds the excitation coil of a relay (43), which provides the additional switching contact. The drive is provided by an electric motor.

Safety contact for machine protection cover - stops machine when cover is removed using inverted U shaped pin assembly

Abstract: To prevent accidents when a machine cover is lifted off or slid away from a machine it is necessary to ensure that the machine is stopped before or at least during the removal of the cover. The safety contact used consists of a two or multi-pin plug (1) which is attached to the cover and which engages with a socket (2) which is attached to a stationary part of the machine or cover. The wires connected to the pins of plug and socket form part of an electrical power circuit. Interruption of the circuit will either stop the machine directly or via a relay.