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4593233 |
Lamp drive circuit
An alternator circuit comprises an alternator having an armature winding, a field winding, a voltage regulator, a fault detecting circuit, a lamp drive circuit having its input connected to the...
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4584623 |
Electrical load protection device
Electronic circuitry senses over-voltage and under-voltage within narrow threshold limits, and voltage interruption, in the energization circuit of a sensitive load, such as a refrigeration...
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4571690 |
Arithmetic operation apparatus using solar cells
Two different set voltages are respectively compared with a power source voltage. When the smaller set voltage which is close to a minimum operating voltage of an arithmetic circuit coincides with...
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4541029 |
Over-load and light-load protection for electric machinery
An apparatus for protecting machinery driven by electric motors from operating during over-load and light-load conditions, comprising: a current transformer operatively associated with an...
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4520418 |
Reset circuit
A reset circuit which monitors the voltage of the power supplied to a microprocessor unit, and produces a low resistance to ground at the reset terminal of the microprocessor whenever the supply...
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4514665 |
Current limit control circuit
Apparatus (10) is provided for controlling current through a motor (12), including a circuit (14) for generating motor speed command data, a circuit (26) for generating a control signal in response...
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4507713 |
Wide frequency multi-phase undervoltage detection circuit
A multi-phase undervoltage detection circuit is disclosed wherein a multi-phase input voltage is compared to a reference. If the peak level of the input voltage is above the reference, a capacitor...
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4503479 |
Electronic circuit for vehicles, having a fail safe function for abnormality in supply voltage
An electronic circuit for use in a vehicle equipped with an internal combustion engine. The electronic circuit comprises a constant-voltage regulated power-supply circuit, a control circuit having...
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4493000 |
Power on/off protect circuit
A simplified power on/off protect circuit is provided to enable logic above a predetermined power supply voltage level and disable the logic below such predetermined voltage level. The circuit...
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4454555 |
Voltage sensing and load measuring automatic reclosing system for d-c circuit breakers
A reclosing system for d-c feeder circuit breakers used on transit systems is disclosed. Circuit breaker closure is prevented when the feeder circuit voltage is in a predetermined voltage range and...
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4449080 |
Electric vehicle protection scheme
A fault detection and inhibit circuit for a power control unit in an electric traction motor propelled vehicle of the type wherein the power control unit includes a chopper circuit and a bypass...
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4447846 |
Computer environment protector
A computer power/temperature protector is provided. A control and disconnect circuit is responsive to a power interruption to disconnect power from a computer to which the protector unit is...
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4428020 |
Power supply sensing circuitry
Power supply sensing circuitry comprises a first comparator for determining whether the power supply potential voltage exceeds by a predetermined amount the voltage required to operate a data...
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4418395 |
Digital data processing system with a value setting unit for protecting and controlling an electric power system
A digital data processing system for protecting and controlling an electric system, wherein plural data values indicative of system limits are generated and supplied to a processing unit for...
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4402029 |
Protective circuit for output transformer-less circuit
A protective circuit for a class B OTL circuit such as a vertical deflection circuit and a sound output circuit of a television set. The protective circuit comprises a first voltage comparator...
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4400657 |
Triac failure detector
A failure detector is provided for detecting unidirectional failures in triacs, particularly as used in power factor controllers for induction motors. In a first embodiment, the triac voltage...
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4368499 |
Electrical equipment protection apparatus
A circuit apparatus including a circuit interrupter connected between an AC supply and electrical equipment to be protected and operational in a first condition to transmit power therebetween and...
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4346307 |
Voltage-unbalance detector for polyphase electrical systems
A detector for high-voltage, polyphase gear, having a fuse-switch combination in each phase and a switch operator, includes voltage sensors which provide first time-varying signals indicative of...
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4333119 |
Power monitor system
Electrical apparatus to monitor electrical three-phase power includes circuitry to protect three-phase equipment from excessive variations in line voltage, phase to phase unbalance, and reverse...
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4333050 |
Multiphase voltage monitor
A monitor for a polyphase power line continuously compares the voltage on each phase of the power line with reference voltages that are selected percentages above and below the average of the power...
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4327397 |
Computer power/temperature protector
A computer power/temperature protector is provided. A control and disconnect circuit is responsive to a power interruption to disconnect power from a computer to which the protector unit is...
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4310867 |
Voltage responsive switch with input voltage surge protection
A high gain voltage responsive current source supplies emitter current to a lateral input PNP transistor in a monolithic integrated circuit voltage responsive switch and, in conjunction with an...
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4306270 |
Electrical system monitoring means
An electrical system monitor is shown as employing a quad-chip C-MOS integrated circuit for sensing when the voltage of a monitored circuit, monitored sub-circuit, monitored branch circuit or...
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4302792 |
Transistor protection circuit
A circuit is described for protecting a semiconductor junction device such as a transistor against damage from high voltage transients that can be produced by kinescope arcing in a television...
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4302791 |
Power supply sequencing apparatus
A power supply sequencing apparatus utilizing a pair of MOS-FET devices to simultaneously apply or remove the positive and negative power supply sources to an electronic unit.
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4238696 |
Failsafe electrical circuitry
A fail safe control circuit in which an input signal for initiating control of a potentially dangerous system is amplified only if it lies between given limits and also only if electrical power is...
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4184187 |
Unbalanced DC voltage detecting circuit
An unbalanced DC voltage detecting circuit which includes first and second switching transistors with one connected to the output terminal of a power amplifier through a low pass filter and the...
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4156280 |
Utility monitor for detecting and storing power line disturbances
A utility monitor for detecting and storing power line disturbances is provided which includes peak-voltage sensing means for over-voltages which provides an interrupt signal at the time of a...
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4091292 |
Fail-safe monitor of d.c. voltage
In some circumstances it is important to maintain a d.c. potential within a specific range of a critical value. The circuit shown will provide a fail-safe signal if the potential deviates from the...
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4084206 |
Protection circuit for serially connected thyristors
A protection circuit for protecting the thyristors of a series circuit of several thyristors, each of which has a corresponding firing circuit to which its anode-cathode voltage is applied. The...
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4073004 |
Power supply with voltage protection circuit
A display and power supply system in which the power supply uses a switching frequency which is higher than the highest linear deflection rate used in a cathode ray tube display device supplied by...
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4063302 |
Protection arrangement for an inverter
A protection arrangement for an inverter having fuses connected in series with its d-c inputs is disclosed. In particular, in one form of the arrangement, an electronic voltage monitoring device is...
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4063148 |
First house protector for voltage regulators and the like
A control circuit for limiting the output voltage of a voltage regulator or the like to a safe level for consumers connected close to the voltage regulator. The output voltage of the regulator is...
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4040116 |
Power supply employing a short circuit detector
A short circuit detector is provided for a compact power supply system in which a plurality of power supplies may be operated in parallel. The detector senses when a voltage drop in a bus indicates...
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3969635 |
Voltage condition monitor
A device for monitoring a variable voltage supply level is disclosed. The monitoring device functions to supply a signal which may be used to shut-down that equipment being supplied and/or drive an...
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3965295 |
Protective system for stereo loudspeakers
In an amplification system comprising an amplifier, a loudspeaker, normally open contacts connected in series between the amplifier and the speaker, and a power supply for the amplifier having...
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3875463 |
Motor protection circuit and automatic restart control system
Excitation voltages applied to an electric motor or other loads are monitored to guard against excessive voltage, insufficient voltage, and voltage imbalance, which includes single phasing,...
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3863125 |
Safety circuit for rapidly switching off oscillators, particularly transistor DC-DC converters, when the output voltages or output current exceed or full below the required values
In a dc-dc converter using a transformer coupled oscillator a threshold switch connected to the dc output of the converter provides a control signal when the voltage and current output parameters...
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3860855 |
MULTIPLE VOLTAGE SOURCE IMBALANCE DETECTION AND PROTECTION CIRCUIT
Voltage protection circuitry for sensing imbalance of the balanced positive and negative voltage sources is disclosed. When imbalance is detected, the sensing circuitry activates protection devices...
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3843907 |
ADJUSTABLE OVER-CURRENT DETECTOR
An over-current detector monitors the current delivered by each section of a multi-section switching regulator and provides a signal for disabling the switching regulator when the current in any...
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3836790 |
A-C VOLTAGE DETECTOR
A circuit for detecting whether the peak magnitude of one or more phases of a polyphase voltage has varied outside of acceptable high and low voltage limits. A high voltage detecting network...
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3818273 |
BARRIER ISOLATOR DEVICE EMPLOYING AN OVERLOAD PROTECTION CIRCUIT
A barrier isolator device is disclosed for interconnecting a voltage source in a safe area, a load (such as a sensing element) in a hazardous area, and a load-associated device (such as a recorder)...
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3813667 |
THREE-PHASE POWER DISTURBANCE MONITOR
A three-phase power disturbance monitor for sensing and recording anomalies ccurring in electrical power systems which cause operational malfunctions in, and damage to, critical loads such as...
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3800198 |
PROTECTION MEANS FOR PREVENTING OVERVOLTAGE AND UNDERVOLTAGE CONDITIONS IN POWER CIRCUITS
An electrical power system includes power conversion apparatus for receiving electric power from a source and supplying the electric power in converted form to a load and control apparatus for...
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3781636 |
LEAD NETWORK TO PREVENT VOLTAGE OVERSHOOT IN A SWITCHING REGULATOR
Voltage overshoot is prevented by coupling the voltage from the input lead of the filter circuit to an error amplifier. A capacitor, resistors and diode provide coupling while the voltage at the...
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3766510 |
VOLTAGE SENSOR AND METHOD OF USING SAME
Metal sulfide compounds and metal phosphate compounds are combined in a selected manner to form a resistance material for a stable sensor having a variable resistance characteristic in response to...
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3748537 |
PROTECTION DEVICE FOR HAMMER DRIVING CIRCUITS
The protection of a plurality of current pulse circuits, for example of the type used to activate high speed print hammers, is provided by a device which monitors the voltage levels at an...
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3708723 |
LOW POWER MAGNETIC CIRCUIT BREAKER
Disclosed is a circuit breaker which may be operated on relatively low power. It comprises a polarized relay having a spring-biased armature rotatable to trip a conventional circuit breaker toggle....
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3694662 |
CROSS REFERENCE POWER SUPPLY
A cross reference regulated power supply including a first regulated power supply having an output terminal for establishing a positive regulated voltage thereon, a second regulated power supply...
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3691427 |
PROTECTIVE CIRCUIT FOR AN ALL STAGE DIRECT-COUPLED TRANSISTOR OUTPUT TRANSFORMERLESS-OUTPUT CONDENSERLESS AMPLIFIER
A protective circuit comprises a detecting circuit for detecting an unbalanced DC voltage developed in an output of an all stage direct-coupled transistor output transformerless-output...
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