Showing papers on "Relay published in 1969"

In-the-large stability of relay and saturating control systems with linear controllers

Abstract: It is shown that when the plant of a relay control system consists of a pure integrators, with n ≥ 3, and the control signal proceding the relay is a linear combination of state coordinates, the system is unstable in-the-large for all values of the controller coefficients. The same result holds if the relay is replaced by a. saturator. The method used is to prove that (except for a degenerate case) state trajectories exist which go to infinity. This method enables more general systems to be treated than those discussed in a previous paper, which demonstrated the existence of a periodic solution. Plants not consisting of pure integrators are also considered. The question of when it is worthwhile to incorporate non-linearities in the controller is discussed.

Digital computer-industrial controller system and apparatus

Abstract: A small general purpose digital computer is utilized as the basic element of an industrial controller. The digital computer is provided with an executive program comprising function simulating modules. Relay logic, timer and counter simulating modules are disclosed. The modules provide an iterative format for a control circuit to be simulated the format comprising a large number of identical parallel circuit lines each controlling a numbered relay. Each circuit may have a specified number of basic electrical elements connected in series with its relay. The types of electrical elements disclosed are a normally open switch, a normally closed switch, a branch function, and a wire connection or no function. The condition of any particular one of the first three types of electrical elements is controlled by a specified one of the number of relays. A control program comprises a particular choice of electrical elements entered in the circuit lines of the ladder diagram to correspond to an actual circuit diagram of a desired control circuit. The system is provided with a simple detachable programming panel or console with which an ordinary industrial engineer having no computer programming experience can program his control program by positioning each required basic electrical element in the format provided and specifying the relay of another circuit line controlling the condition of the elements. He enters the set time for each relay which is to be timer controlled. An internal clock is provided for the timing function. He also enters the total count and the simulated relay whose cycles are to be counted for each relay which is to be counter controlled. A plurality of the numbered relays may each be conditioned only by an external device connected to an identically numbered input terminal. Another plurality of the numbered relays each control the signal supplied to an identically numbered output terminal which may be connected to external devices. In use, the executive program continuously and repeatedly runs through the ladder diagram control circuit line by line, updating the condition of each electrical element in accordance with the referenced numbered relay; updating the condition of each numbered relay in accordance with the condition of the electrical elements or input terminal in circuit therewith; and updating the condition of each output terminal in accordance with its associated numbered relay. Provision is made for communicating with the computer controller via ordinary telephone lines from a central station. The original computer controller is delivered to a customer with the executive program in memory. The control program is added by the customer through the detachable programming console. Both the executive and customer chosen control program can then be read out to the central station and printed or recorded on punched tape for full documentAtion thereof. Further units can be supplied to the customer preprogrammed through use of the punched paper tape. The central station also can communicate with a remote computer controller by means of a central programming console and has the ability to diagnose breakdowns of the computer controller and readin to or readout from any memory location in the remote computer controller.

Overload and overcurrent regulation and protection system

Abstract: An overload and overcurrent regulation and protection system and circuit are disclosed for a polyphase electric motor in a refrigeration system of the type including adjustable mechanical load decreasing means, such as adjustable prerotation vanes on a refrigeration centrifugal compressor. The system and circuit provides for varying types of overload conditions: continuous low overload, short term high overload, or for intermediate overload situations; before automatically operating a safety deenergizing relay switch. A time delay provides time for corrective measures to be instituted by the mechanical load decreasing means and allows transient overloads occasioned by normal conditions, such as starting or shifts in mechanical load, to be accommodated without unnecessarily disabling the motor. The circuit includes a rectifying circuit for deriving a DC signal proportioned to the maximum AC current in any one of the phases windings two pairs of Schmitt Trigger circuits employing solid state Operational Amplifier devices operated from a voltage dividing circuit and sources of different valued DC standard signals, for respectively producing an overload signal of one of four types, representing respectively small and large overloads, a single unijunction transistor timing circuit operated by one pair of the Schmitt Triggers, an SCR-controlled relay for operating a motor deenergizing device such as a relay in response to the timing circuit. The other pair of Schmitt Triggers function to control the mechanical load decreasing means to allow for correction of small overloads without unnecessarily deenergizing the compressor motor.

Subscriber loop range extender

Abstract: This disclosure describes a telephone subscriber loop range extender having a signaling mode and a transmission mode. In the former, a resistive shunt is applied across the loop with each dial pulse to aid operation of the pulsing relay for an originating cell. For a terminating call, the shunt is applied upon answer, either during ringing or during the silent interval, to aid operation of the ring-trip relay. In the transmission mode, voice frequency gain and greater transmitter voltage are applied to the loop. A control circuit consisting of logic, timing and relay driving circuits, acts upon loop voltage and current data to control shunt action and mode selection.

An Underfrequency Relay with Frequency Decay Rate Compensation

Abstract: The development of a new type of solid-state protective relay which senses both frequency and rate-of-change of frequency is outlined The design considerations and principles of operation of this relay are explained with respect to modern load reduction concepts The theory of operation of the device and how it can be applied in an electric power system are discussed Finally, possible future applications of the philosophy of rate compensated protection are presented

Photoelectric relay using optical couples

Abstract: Disclosed is an isolator switch or relay for isolating an electrical input and output. It comprises a pair of optical source-detector couples in which the sources are alternately overdriven over a low duty cycle to provide a rapid response. Input and output logic elements are connected to the couples, the former providing alternate time-spaced signals to the couples and the latter recovering the polarity of the input signal. Improved electromagnetic isolation between opposite sides of the couple as well as strobing and termination circuits are provided. The switch is adapted for use in all types of digital data communication circuits.

Automatic reversing circuit for a window regulator motor control system

Abstract: A window regulator motor control system for a drive motor operative to open and close a window includes an automatic reversing circuit incorporating an overload current relay and a reversing relay which function to reverse the motor in response to an overload current condition. The reversing relay is energized through a controlled rectifier gated conductive by a triggering circuit including a resistance-capacitance time delay network connected to the overload current relay. When the window is driven against an obstruction, the time delay network provides a momentary delay before the controlled rectifier is gated conductive and the motor is reversed.

Furnace having multiple speed motor and accessory control system

Abstract: A HEATING AND COOLING SYSTEM INCLUDING A FURNANCE HAVING A CONTROL MODULE COMPRISING A PREWIRED PRINTED CIRCUIT BOARD HAVING A PAIR OF LINE VOLTAGE CONDUCTORS CONNECTED TO THE PRIMARY WINDING OF A POWER TRANSFORMER AND A PAIR OF LOW VOLTAGE CONDUCTORS CONNECTED TO THE SECONDARY WINDING OF A POWER TRANSFORMER. TERMINAL MEANS ARE PROVIDED FOR CONNECTING A PLUG-IN FAN RELAY AND A THERMOSTAT IN THE LOW VOLTAGE CIRCUIT. ADDITIONAL TERMINAL MEANS ARE PROVIDED FOR CONNECTING A FAN MOTOR AND A HUMIDIFIER AND HUMIDIFIER RELAY TO THE LINE VOLTAGE CIRCUIT. TERMINAL MEANS ARE ALSO PROVIDED IN CONJUNCTION WITH A DOUBLE-POLE, DOUBLE-THROW FAN MOTOR RELAY SWITCH FOR CONNECTING AN AIR CLEANER ACCESSORY UNIT TO THE CIRCUIT. THE CIRCUIT IS ARRANGED TO PROVIDE THE DESIRED OPTIMUM PROGRAMMING OF CONTROL FUNCTIONS WITH AN COMBINATION OF ACCESSORIES.

Field weakening circuit for a series field motor

Abstract: A speed control circuit for a series field direct current motor. The circuit includes a reed relay that has a movable contact responsive to the current flow through the field and a resistance in a shunt circuit with the field. The reed relay through a transistor and a contactor causes the shunt circuit to be interrupted when the current flow through the motor increases above the predetermined value. The reed relay has a pair of coil windings arranged so that one of the windings generates a magnetic flux that opposes the flux generated by the current flow through the field and the other provides an output flux which adds to the flux generated by the field current so that movable contact will operate with a snap action. The flux outputs of each of the pair of coils is individually adjustable so the response of the relay to the upper and lower limits of a range of field current flow may be individually adjusted. The circuit further includes a capacitor which will cause the flux output of one of the coils to momentarily increase when the reed relay initially responds to an excess current in the field circuit.

Condition detection and alarm system

Abstract: A condition detection and alarm system is disclosed having a normally inactive detector relay in series in a detection circuit with a normally open-circuited alarm sensing device that is connected in multiple with a resistor to permit supervising of the circuit. In response to actuation of the detector relay, an alarm circuit becomes energized for actuation of at least one alarm device. A single transistor switch is provided for supervising both the detection circuit and the alarm circuit, the detection circuit being supervised in a biasing circuit for the transistor, and the alarm circuit being supervised in the output circuit of the transistor. Failure of the transistor to provide an output is manifested as a trouble condition.

Remote control circuits

Abstract: A remote control circuit for controlling the application of power to a load by latching and unlatching a relay. The relay is controlled by a capacitor which is coupled to the relay by means of a plurality of switches which may be placed at different locations. The condition of the capacitor and its location in the circuit are selected such that current through the relay is alternately increased and decreased sufficiently to cause latching and unlatching in response to successive momentary closings of any of the switches.

Ground relay system for multiple substation protection

Abstract: A ground relay system for multiple substation protection employing a plurality of current transformer sensors. In a threephase electrical system, one such current transformer is connected to sense the current flow from ground to the common neutral conductor for the multiple sources employed and serves to trip a circuit breaker connecting these multiple sources in a summing relationship when a ground fault is indicated. At the same time, the remaining current transformers serve to sense the current flow in the neutral conductor of the system and relay circuits activated thereby are conditioned by the operation of the first such current transformer to trip the circuit breaker or breakers associated with that portion of the system in which a ground fault is present. D R A W I N G

Safety control circuit for presses and the like

Abstract: An electrical control circuit for a multicontrolled machine having manually operates switch means operated by respective self-returning manually operable control means at a number of operator stations, all of which switch means must be operated at the same time to initiate movement of a work producing portion of the machine. The manually operated switch means includes normally open switches in a drive control relay circuit and normally closed switches connected in parallel between a manually controlled relay and a source of power so that the manually controlled relay cannot be deenergized until all of the normally closed switches are opened and will not become deenergized until all of the normally closed switches have been closed. The manually controlled relay operates normally closed switch means in the drive control relay circuit, and normally closed switch means in an antirepeat relay circuit which prepares the drive control relay circuit for energization by closure of all of the normally open manually operated switch means.

Circuit breaker for the lighting systems of vehicles

Abstract: A compact, solid state, switching circuit which functions as an automatic circuit breaker for the lighting systems of a motor vehicle comprises a relay, energized through an electronic switch which is gated off, preferably after a time delay, when the ignition switch of the vehicle is opened.

Emergency lighting system for using auxiliary light system

Abstract: An emergency equipment to cope with the failure of headlamps while a motor vehicle is running comprising headlamps connected to a power source through a main switch and a dimmer switch, a logical circuit connected to circuits of the hkadlamps, and auxiliary lights connected to the power source through a relay. The emergency equipment is characterized in that when one or all of the headlamps fail while the main switch is closed, the logical circuit and hence the relay are operated, whereby the auxiliary lights are turned on.

Electrical fault protection system

Abstract: A normally open relay and a normally closed relay responsive to fault currents in an electrical distribution system control the opening of a disconnect switch incapable of interrupting large fault currents. The contacts of the relays are connected in series in an energizing circuit for an electroresponsive operator of the disconnect switch. Upon occurrence of a small fault, such as a ground fault, the contact of the normally open relay closes after a short time delay to effect opening of the disconnect switch. Upon occurrence of a large fault, the contact of the normally open relay also closes as for a small fault, but the contact of the normally closed relay opens instantaneously to prevent opening of the disconnect switch.

Power control system

Abstract: A relatively low power level electrical signal is utilized for controlling the switching action of a plurality of relay networks in a power control system so as to control the AC power being supplied to a load A plurality of switch branches are provided each including an AC power switch having a pair of power terminals and a control electrode arranged to carry a relatively high power level signal through its power terminals Energization of the power switch is effected by the application of a relatively low power level signal to its control electrode through a switch such as a pair of relay contacts which need have only a relatively low power-handling capacity in comparison with the power level to be supplied across the power terminals of the AC power switch A selectively energizable relay coil is serially connected to the power terminals and is operatively coupled to a pair of relay contacts in a succeeding switch brand, which in turn, are coupled to the control electrode of another similar AC power switch, and, upon closure energize this another power control switch so that the AC power signal flows through its power terminals in order to energize a load coupled thereto The relay contacts coupled to the control electrode need only be sufficient to carry a relatively low power level signal in order to energize the another AC power switch, while the load power signal flowing through the power terminals may be at least an order of magnitude greater than that supplied to the control electrode for rendering the another power switch conductive

Time delay extender for static relays

Abstract: A static relay using a resistance-capacitance network has a current-time characteristic which has an inverse relationship. The input to the network is connected through a free-running multivibrator which has an adjustable conduction period. Adjustment of the conduction period adjusts the time delay characteristic of the network over a large range without altering the time delay wave shape.

Ultrasonic detection system

Abstract: An ultrasonic detection system having a transmitter for producing a beam and receiver for receiving and converting the beam to an electrical AC signal and for amplifying the AC signal. A detector converts the amplified AC signal to a DC voltage, and a variable sensitivity control produces a voltage pulse upon a substantial change in the amplified AC signal resulting from a sufficient temporary interruption of the beam by an intruder. A relay control selectively completes the current path between a power source and a relay with the relay control being actuated upon occurrence of the voltage pulse. The variable sensitivity control includes a potentiometer for varying the bias supplied to a transistor, transistor being biased below conduction. The detector includes means for increasing the bias supplied to the transistor above conduction upon a sufficient temporary interruption of the beam by an intruder whereupon the transistor produces the voltage pulse for actuation of the relay control. The relay control includes a silicon controlled rectifier which completes the current path through the relay upon occurrence of the voltage pulse by the transistor.

Multiphase motor control system with overcurrent and undercurrent protection

Abstract: A multiphase motor control system includes an indicator and detector assembly having a meter relay for each phase circuit. Each meter relay has a pair of light-activated silicon controlled rectifiers (LASCR''s) which are normally conductive when illuminated from a pair of lamps indicating the phase current is below a high level setting, and above a low level setting. If any phase current exceeds the high level setting, the meter movement displaces a shutter which blocks the light from the high-current lamp, deenergizing the LASCR and deenergizing a first control relay, which is coupled to all the high-current circuits, to shut down the system. Correspondingly, decrease of any phase current below the preset low level causes a reduction of illumination on the low level SCR, and drops out a second control relay, also coupled to the other low-current circuits. The control circuit includes the first and second control relays and associated components for regulating, consonant with suitable time delay, energization and deenergization of the motor. A single power supply energizes the meter relays and the control relays in the control circuit.

Circuit for improving relay performance with current limiting

Abstract: A transistor circuit for controlling energization of a DC relay coil forms a low impedance path through the transistor upon initial application of voltage and allows a fast coil current rise that increases the operating speed of the electromagnetic relay under a broad range of temperature conditions without exceeding coil current limitations. As the current increases to a predetermined value, the transistor control circuit is operated to provide a current limit action. The circuit is also designed so that it will continue to allow relay operation, although with an increased operating time, provided there is minimum required pickup voltage, in the event any one of the components fails.

Vehicle alarm system

Abstract: The invention provides a protective alarm system for a vehicle by sounding an alarm when the vehicle is tampered with or entered during the owner's absence. A first set of switches, including an inertia switch, is connected by a normal sensing relay to sound the alarm immediately if the vehicle is shaken or tampered with in other ways. A second set of switches is provided to set up an alarm condition by holding relay and a thermostatic delay relay if normal entry is gained to the vehicle, as by opening a door, but will not sound the alarm during a predetermined 15 second delay. Turning the ignition on during this 15 second entry period disables the entire alarm system by way of a de-activating relay and a further thermostatic delay relay. When the ignition switch is turned off the further delay relay provides a 120-second non-alarming period for exit from and locking of the vehicle.

Time delay bimetallic relay

Abstract: A relay employing two slotted bimetallic blades mounted substantially parallel and overlapping at their free (unmounted) ends with a heater element associated with one of the blades.

Rf coaxial relay

Abstract: A radio frequency (RF) coaxial relay for connecting either of two coaxial terminals coupled, respectively, to a radio receiver and a radio transmitter, to a third coaxial terminal coupled to an antenna, includes a pair of magnetically actuated reed switches located within a cast nonmagnetic conductive housing. The reed contacts are capable of carrying high currents but are incapable of switching high currents, so that a sequencing circuit is provided so that the contacts of the reed switch coupled to the transmitter do not switch the transmitter when power is applied therefrom. In addition, the switch leaves of the reeds are copper-plated in order to cause the RF resistance of the reed switches to be low. 0This application is a continuationin-part of application, Ser. No. 722,319, now abandoned filed Oct. 31, 1968.

Switching device for power supply circuit

Abstract: In a relay device provided with means for decreasing the exciting current to a value substantially less than the pickup current and adapted to connect a power supply to a load, a protective switching means responsive to faulty conditions of the power supply or load is provided to short circuit the exciting coil of the relay.

Overvoltage and electronic relay circuit for capacitor discharge ignition systems

Abstract: An energy-pulsing circuit is provided for reestablishing a predetermined energy level within a storage capacitor after the energy therefrom has been applied to the ignition coil in response to external pulse signal information. A power-switching circuit is connected between the energy-pulsing circuit and an external power supply to block current flow to the energy-pulsing circuit during one instance, and to provide a current path to the energy-pulsing circuit during another instance. A synchronized oscillator is provided for controlling current flow through the power-switching circuit during desired periods of time, the oscillator circuit being synchronized with the external pulse signal information.

Frequency-responsive control circuit

Abstract: Phase shift caused by a band-pass filter is employed for providing a voltage proportional to the deviation in frequency of an input signal from a reference level. This arrangement is incorporated in a relay control circuit for an electric power network load shedding system which includes an adjustable level trigger circuit for establishing the flat tripping frequency, an adjustable differential amplifier circuit for establishing an inhibit frequency, and a rate circuit for advancing the tripping frequency as a function of the rate at which system frequent drops. An adjustable time delay circuit prevents the relay from operating in response to transients.