Showing papers on "Relay published in 1970"

Protector circuit for cardiac apparatus

Abstract: A protector circuit having relay arrangement and gas discharge tubes coupled between first electrodes attached to a patient and the amplifier of an electrocardiograph, the relays comprising fast acting reed relays which break the circuit when a defibrillator is energized to apply a countershock voltage across second electrodes mounted on said patient, to prevent the countershock voltage from distorting the heartbeat waveform produced by the electrocardiograph. The gas discharge tubes prevent voltages in excess of a predetermined value from reaching the amplifier by conducting such voltages to ground, whether the relays are opened or closed.

Relay contact protecting circuits

Abstract: A contact protecting circuit for a relay having its operating coil energized from a DC supply and its contact controlling an AC load circuit. A triac connected in parallel with the contact conducts before the contact closes and after the contact opens to protect the contact from electrical arcing. In a first version, the triac is controlled by a secondary winding magnetically coupled to the relay coil. In a second version, the triac is controlled by a transformer connected in parallel with the relay coil. In this manner, the triac is gated only for a short time interval when triac conduction is needed and the triac will not continue to conduct in the event the relay contact fails to close.

Short circuit locator apparatus including a plurality of intermittently operated circuit breakers

Abstract: A method and apparatus for locating short circuits, primarily in a vehicle, which comprises of placing a pair of test leads across the defective fuse in a shorted circuit, the test leads being connected to a plurality of circuit breakers through a selector switch for selecting one of the circuit breakers. A relay in parallel with the selected circuit breaker operates a switch which controls a light and tone generator, such that when the circuit breaker is placed across the fuse terminals of a shorted circuit, an audible and visual signal will be generated by the tone generator and light.

Relay control responsive to overvoltage and undervoltage

Abstract: A line voltage guard circuit having a network including neon lamps, resistor-capacitor timing branches, diodes and transistors, the network being connected to a switching relay to control the availability of the supply line voltage to apparatus utilizing same and to disconnect the supply line from the apparatus when the line voltage is either below a bottom limit for a definite length of time or above a top limit. The circuit automatically reconnects the line to the apparatus a predetermined time after the supply voltage returns to a value between the top and bottom limits.

Electrical supervisory control

Abstract: A control circuit is connected into the electrical system of a vehicle such as an automobile having a starting motor, a battery, and various current-consuming load devices, such as headlights. A relay-operated switch is connected between the battery and the load devices. A potentiometer is connected across the battery, and the relay winding and a transistor are connected across the potentiometer with the potentiometer slider connected to the base of the transistor and the collector connected to the relay winding. The resistance values are chosen such that when the battery is substantially charged, the voltage across the baseemitter junction of the transistor is sufficient to keep the transistor conducting, thus causing the relay to be energized and the switch to be closed, connecting the load devices to the battery. Should the battery be run down, as through leaving the headlights on, the battery voltage will drop, and at some desired proportion of full charge the voltage across the base-emitter junction will become too low to keep the transistor conducting, and the relay will drop out, opening the switch and disconnecting the load devices. A reset switch is provided to reconnect the remaining battery voltage across the relay winding.

Polarity control system

Abstract: A system for controlling the transmission of electrical power between a D.C. power source and a load. The system includes a circuit having indicator lamps for visually indicating the polarity of the power source and of the load. Relays are utilized to prevent power transmission when the source and the load are improperly connected to the circuit. The circuit includes normally closed contacts of one relay in series with the coil thereof and a resistor in parallel with the normally closed contacts so that when the coil is energized, the voltage applied to the coil is automatically reduced during operation.

Improvements in electrostatic relays

Abstract: A relay is provided which includes a drop of conducting liquid, for example mercury, and means for subjecting the drop to an electro-static field to effect movement of the drop between at least two positions. This movement causes the conductive drop to interconnect different contacts, switching the relay from one state to another.

On Determining the Reliability of Protective Relay Systems

Abstract: This paper lays the ground work for the statistical determination of the reliability of protective relay systems found in electric power systems. The reliability problem has two conflicting requirements: 1) failure to operate in the presence of a fault and 2) unnecessary operation when a fault occurs that the relay or relay system was set to ignore. It is not often treated in reliability literature.

Solid state relay

Abstract: A solid-state switching device capable of replacing mechanical relays. When the relay is conducting rated load current, a single saturated transistor carries the current with a very low voltage drop. When the load current rises above a pre-determined level, the load-carrying circuit automatically becomes a modified Darlington circuit, which is capable of carrying substantial overloads without being damaged, and with voltage drops within a desirable range. Optionally, means are provided for disabling the load circuit and, in effect, opening the relay, when a certain level of overload current is reached, thereby turning the device into a circuit-breaker.

Optimum performance spacecraft solar cell system

Abstract: A spacecraft solar cell system including a switching circuit which comprises relay operated switches for changing a plurality of solar cells from a first series-parallel interconnection to a second series-parallel interconnection is disclosed. The relays are actuated by a command device which may be a telemetry receiver. A protection circuit comprising a photodiode is connected between the command device and the relays to ensure appropriate solar cell orientation when switching occurs. This prevents arcing across the relay switches.

Time delay control

Abstract: A time-delay control for applications such as operation of an internal combustion engine, where continued idle operation of the engine is desired after removal of the key from the usual controlling switch. A manually operated switch is connected between the load side of the controlled switch and a timed electrical relay for selectively energizing the relay while the engine is operating. The relay includes contacts in parallel with the manually operated switch and contacts in parallel with the controlled switch. The relay continues engine operation for a reset time, during which the key may be removed. At the conclusion of this period, the relay is de-energized and the engine is automatically shut down.

One-way motion detection switch

Abstract: Apparatus including a signal generator for activating warning devices to alert the operator of a motor vehicle, the signal generator being controlled by circuitry including reed switch systems opened and closed by the movement of magnets with the N-S axis thereof passing across the longitudinal axis of the switch system or perpendicular to such axis for controlling a variable timing circuit or a relay.

Off-delay solid-state timer systems

Abstract: AC and DC solid-state timers for controlling loads such as electromagnetic relays or the like. The timer is supplied through a rectifier from the AC source and provides a time delay after opening of the control circuit; that is, when the control switch is moved to "off" position, the timer delays drop out of the relay for a predetermined, adjustable time interval. The timing can be cancelled at any time before relay dropout by moving the control switch back to "on" position and this will not affect relay energization. A second version works equally well on AC or DC power. A third version returns the load to the condition it was in before power failure when the power comes back on.

Reflective relay optical system for two-axis deflection

Abstract: A REFLECTIVE OPTICAL SYSTEM IS PROVIDED WHICH SERVES BASICALLY TO RELAY A LASER, OR OTHER, BEAM FROM A FIRST DEFLECTOR OF A SECOND DEFLECTOR IN ORDER TO ACHIEVE TWO DIMENSIONAL SCANNING OF THE BEAM. A SPHERICAL MIRROR IS USED IN THE RELAY SYSTEM TO ACHIEVE OPTICAL COUPLING BETWEEN THE TWO AXES OF BEAM DEFLECTION. THE RELAY OPTICAL SYSTEM OF THE INVENTION, THEREFORE, IS REFLECTIVE, AND IS LESS SUBJECT TO OPTICAL LOSSES, LESS EXPENSIVE, AND EASIER TO ALIGN, THAN THE PRIOR ART REFRACTIVE RELAY SYSTEMS. ELECTRONIC MEANS MAY ALSO BE PROVIDED IN THE RELAY SYSTEM OF THE INVENTION TO COMPENSATE FOR ANY INTERACTION PRODUCED BY THE SYSTEM BETWEEN OTHERWISE ORTHOGONAL SCAN AXES.

Transistorized flasher circuit

Abstract: A transistorized flasher circuit for vehicle signal lamps comprising a free running multivibrator, incorporating a capacitor and a programmable unijunction transistor, for cyclically and intermittently driving an output transistor into a conductive state as the capacitor is alternately charged and discharged. A relay is provided and includes a coil connected in series with the output circuit of the output transistor and a set of normally open contacts which are connected in series with a lamp load and a start switch and which are closed in response to the energization of the coil. A charging circuit including the capacitor and a diode connected in series therewith is connected in parallel with the set of relay contacts for charging the capacitor along a first path when the set of relays contacts open. A discharging circuit is provided for discharging the capacitor along a second path, which does not include the diode, when the relay contacts close.

Time delay control system for directional relays with electrical interlock

Abstract: A solid state control circuit for completing selectively energizing circuits for the operating coils of directional relays in a motor control system which affords a predetermined time delay on energization for each relay, and electrical lockout against simultaneous energization of one relay operating coil while the other remains energized and vice versa

On the phase-plane analysis of relay control system with dead time†

Abstract: An exact method of analysis of non-linear systems containing a two-position relay element and a dead-time element is given using the phase-plane concept. Equations of the switching lines for both unsymmetrical and symmetrical relay characteristics are obtained under consideration of the dead time. Expressions to evaluate the period and amplitude of the self-oscillation of the system are derived from the stable limit cycle in the phase plane. This method is developed for a second-order system with a zero in its transfer function. For such a system it is indicated with a help of an example that approximation methods as the describing function yield large errors because the low-pass condition is not satisfied. The phase-plane method will be developed for other relay characteristics.

Fluid level indicator

Abstract: A fluid level indicator utilizing a transistorized relaxation oscillator, which is powered by a DC source, and a probe, which is positioned in a container so as to detect the absence of fluid at some critical level. The probe is either in circuit or out of circuit with the oscillator so that whether the probe is immersed in the fluid or out of the fluid determines the duration of the oscillator output pulses. If the probe is out of the fluid the duration of the output pulses increases enough to energize a relay. The energized relay causes a warning lamp to illuminate and provide a visual warning that the fluid is below the critical level.

Switching system for plurality of audio input

Abstract: Through an electrical switching circuit, electrical signals are transmitted from a source of background sound to a first speaker system. Upon activation of a phonograph, a first relay is activated causing operation of the switching circuit resulting in non-transmission of the background sound and transmission of the phonograph sound to the first speaker system and a second speaker system. A third and fourth source of sound capable of producing electrical signals, when caused to be transmitted through the switching circuit, causes activation of a second relay and deactivation of the first relay. This results in transmission of only the third or fourth source of sound to both the first and second speaker systems. The fourth source of sound is capable of overriding the third source of sound.

Cassette tape playout sensing, indication and protecting means

Abstract: Cassette tape protective means, comprises a tape cassette having a casing in which is a magnetic tape provided with a conductive leader and a conductive trailer at opposite ends. The casing has an opening for exposing the tape to parts of an end-of-tape sensing circuit in a cassette recorder. The end-of-tape sensing circuit includes a pair of spaced wiper contacts, a relay and an alarm device such as a lamp or buzzer. The drive motor of the recorder can be connected in circuit with the wiper contacts and a relay for automatically stopping the motor when the wiper contacts are reached by the trailer and leader.

Fluid logic control system

Abstract: A fluid logic control system for controlling the operation of, for example, industrial machines. The system includes a plurality of fluid-operated components, each of which includes a casing having a chamber, a movable spool in the chamber, ports in the casing, and passageways in the spool. The components include: a fluid logic gate capable of performing any one of the four logic functions: AND, OR, NOT, NOR ; a multiple pole relay; a differential pressure relay; a micro-valve differential pressure relay; a pilot light; a selector switch; and a push button relay. The spools are self-sealing and the casings are interchangeable.

Ground leakage relay circuit

Abstract: A ground leakage relay circuit including a core balance transformer through which pass the supply and return line of the circuit to be protected and having a multi-turn secondary winding. A capacitor is connected to be normally charged from a d.c. source. A normally conducting transistor is connected across the capacitor. When the transformer secondary winding exceeds a preselected level, the transistor is switched "off" to permit a voltage build-up across the capacitor. When the voltage across the capacitor reaches a triggering value, it actuates a relay to open the supply line.

Tracking and Data Relay Satellites

Abstract: A discussion of tracking and data relay satellites is presented, including the TDRS concept of employing geostationary spacecraft to command, track, and relay data from multiple orbiting satellites to central ground stations. Benefits include economic advantages and improved service. A system design and spacecraft descriptions are included.

Switching circuit for electrical devices of motor vehicles

Abstract: A switching circuit for a motor vehicle comprises a plurality of switches for a horn and other electrically operated devices of the motor vehicle, all these switches being disposed on the vehicle steering wheel so as to make common use of a single slip ring of a horn switch provided for electrical connection between the steering wheel and steering post of the motor vehicle in general. Upon closure of the horn switch, a horn relay connected between a bus and the collector of a transistor is energized to sound the horn since then conduction is caused in that transistor, whereas, when the other switches are closed, a constant voltage at a point between the switches and a constant voltage line of the switching circuit is divided into desired fractions by means of resistances provided respectively to those other switches and a fixed resistance provided between the aforesaid point and the constant voltage line. These voltage fractions are utilized to energize desired relays of the devices associated with the switches via transistors, zener diodes and the like.

Solid-state relay

Abstract: A solid-state relay comprising, in place of the coil of an ordinary relay, an electronic circuit including an energy-storage reactive element and a solid-state negative resistance component connected to the reactive element and having a negative resistance or a breakdown or break-over characteristic. In place of the metallic contacts of an ordinary relay, this invention includes solid-state means having a relatively high impedance condition and a condition of relatively low, or substantially zero, impedance. Coupling means, which may include inductive elements, light-emissive and light-sensitive elements, crystals, or other energy transmission elements, connect the "coil" part of the circuit to the "contact" part while providing electrical isolation between the two parts.

Control device for pressure lubricated compressors

Abstract: Operation of an electric motor driving a refrigerant compressor having forced oil lubrication is controlled by a solenoid operated switch, the solenoid circuit including a thermostatic switch in series with a parallel connected timer switch and oil pressure differential responsive switching means. The timer switch is operated by a relay coil energized by a timing circuit which includes voltage biased switching means having alternate output circuits, one of which includes the relay coil. The switching means is controlled by a capacitor which when charged, causes the timing switching means to change the effective flow of current from one output circuit to the other. In one form of the invention the relay coil is connected in initially energized output circuit of the switching means and is shunted to open the timer switch when the switching means is biased to change energization of the output circuits. The pressure differential responsive switch shunts the timer switch to provide a holding circuit for the solenoid after opening of the timer switch and simultaneously deenergizes the timing circuit. In another form of the invention, the relay coil is connected in the other output circuit and is not energized for a period determined by charging of the capacitor to a given voltage. In this form the pressure responsive switch does not shunt the timer switch and is effective to deenergize the timer circuit in response to normal oil pressures.

Circuit for operating polyphase induction motors from single phase supply

Abstract: A circuit for providing the phased currents necessary for starting and operating polyphase motors from a single phase voltage supply. Out of phase currents are obtained by connecting a capacitor to one or more of the motor windings. Upon the motors'' reaching nearly full speed, a potential voltage relay operates to remove the capacitor from the motor circuit. Chatter of the potential voltage relay is avoided by inclusion in the circuit of a series resistor which is selectively shorted by a further relay connected in parallel with the starting capacitor.

Zero voltage switching ac relay circuit

Abstract: An AC relay circuit is disclosed which includes a triac as its active switch element. A full wave rectifier is connected between one of the primary terminals and the gate terminal of the triac. A control switch is provided between the load terminals of the rectifier. First control means are provided which are responsive to an input control signal for closing the control switch, thereby triggering the triac into conduction. Second control means are provided for rendering the control switch nonresponsive to the first control means whenever the magnitude of the AC voltage to be controlled exceeds a predetermined value.

Electrical switch means for effecting sequential operation

Abstract: A creep action switch structure auxiliary to and operating in planned sequence with a snap acting switch is shown. In the embodiment shown, the main switch is part of a time delay relay in which the auxiliary switch provides a shorter heat or cool time relative to the main switch and also provides a means of reducing the total time delay on heating or cooling for multiple relay use.