Thermistor Patents (Class 361/165)
  • Patent number: 12031639
    Abstract: Universal control circuitry for an electro-hydraulic valve actuator system includes logic gate circuitry to control one or more of a closing solenoid valve, an opening solenoid valve, an emergency shutdown solenoid valve, and a hydraulic fluid pump motor to route hydraulic fluid through a hydraulic circuit to actuate a valve via a hydraulic actuator according to received commands. The universal control circuitry is configured to control operation for multiple different configurations of a hydraulic valve actuator system including double-acting configurations, single-acting spring-to-open configurations, and single-acting spring-to-close configurations, each with or without an emergency shutdown arrangement (which may be configured to trip based on an external shutdown input alone or in combination with a local system power failure), a hydraulic accumulator, and maintained or momentary input commands.
    Type: Grant
    Filed: May 10, 2021
    Date of Patent: July 9, 2024
    Assignee: Emerson Process Management Valve Automation, Inc.
    Inventors: Shankar Dhekale, Jason T. Hoffbauer
  • Patent number: 9072132
    Abstract: A lighting control system includes lighting devices arranged along a road for a moving body. Each lighting device includes a sensor that detects a moving body approaching the lighting device, a light source that emits light, a sensor that detects the moving body, a control unit connected to the sensor and the light source, and a communication unit. The sensor of the one of the lighting devices located in at least at one outermost position of the lighting devices has a higher detection frequency than the sensors of the other lighting devices.
    Type: Grant
    Filed: May 9, 2013
    Date of Patent: June 30, 2015
    Assignee: Panasonic Intellectual Property Management Co., Ltd.
    Inventors: Tadashi Murakami, Shigeo Gotoh
  • Patent number: 8988843
    Abstract: The present invention concerns an actuator module (1) comprising an actuating unit (3), said actuating unit comprising a solenoid (31) having a first (31?) and a second (31?) electric terminal, capable, when excited, of generating an electromagnetic field and a PTC (Positive Temperature Coefficient) resistor (32) connected in series with said second electric terminal (31) of said solenoid (31), said actuator module (1) being characterized in that said actuating unit (3) can be controlled by activation signals and protection signals, and in that it comprises a switch circuit (33, 34), connected between said first (31?) and second (31?) electric terminal, said switch circuit (33, 34) allowing the passage of current through said solenoid (31) and said PTC resistor (32) by said activation signals; and preventing the passage of current through said solenoid (31), but allowing the passage of current through said PTC resistor (32), by said protection signals.
    Type: Grant
    Filed: March 18, 2013
    Date of Patent: March 24, 2015
    Assignee: Bitron S.p.A.
    Inventors: Fabrizio Promutico, Enrico Adiutori
  • Publication number: 20140226250
    Abstract: There is provided an electromagnetic operation device for a vacuum circuit breaker, which controls by its electromagnetic operation, a speed of contact switching operation of a vacuum switch tube used in the vacuum circuit breaker, the electromagnetic operation device including a closing drive coil for the vacuum switch tube; and a first temperature sensor that measures a temperature surrounding the closing drive coil, wherein a current caused to flow through the closing drive coil is controlled based on the temperature measured by the first temperature sensor.
    Type: Application
    Filed: December 12, 2011
    Publication date: August 14, 2014
    Applicant: Mitsubishi Electric Corporation
    Inventor: Yasushi Takeuchi
  • Publication number: 20130294000
    Abstract: The present invention concerns an actuator module (1) comprising an actuating unit (3), said actuating unit comprising a solenoid (31) having a first (31?) and a second (31?) electric terminal, capable, when excited, of generating an electromagnetic field and a PTC (Positive Temperature Coefficient) resistor (32) connected in series with said second electric terminal (31) of said solenoid (31), said actuator module (1) being characterized in that said actuating unit (3) can be controlled by activation signals and protection signals, and in that it comprises a switch circuit (33, 34), connected between said first (31?) and second (31?) electric terminal, said switch circuit (33, 34) allowing the passage of current through said solenoid (31) and said PTC resistor (32) by said activation signals; and preventing the passage of current through said solenoid (31), but allowing the passage of current through said PTC resistor (32), by said protection signals.
    Type: Application
    Filed: March 18, 2013
    Publication date: November 7, 2013
    Inventors: Fabrizio Promutico, Enrico Adiutori
  • Patent number: 8248739
    Abstract: An electrical switching apparatus is for another apparatus including a number of insulators, a number of temperature sensors operatively associated with the number of insulators, and a number of conductors operatively associated with the number of insulators. The electrical switching apparatus includes a number of separable contacts, an operating mechanism structured to open and close the separable contacts, a number of sensors structured to sense a number of currents flowing through the separable contacts and through the conductors, a processor structured to input the sensed currents from the sensors, and an output. The processor calculates at least one of: (a) a thermal age of the other apparatus from a number of sensed temperatures from the temperature sensors, and (b) the thermal age of the other apparatus from the sensed currents. The output includes the thermal age of the other apparatus.
    Type: Grant
    Filed: July 24, 2009
    Date of Patent: August 21, 2012
    Assignee: Eaton Corporation
    Inventor: Lawrence B. Farr
  • Patent number: 7498913
    Abstract: A thermal trip device in which a bimetal (2) is heated by overcurrent and performs trip operation of a circuit by curvature of the heated bimetal (2), wherein at least one part of the surface of the bimetal (2) is made to be black or matte black (7). Thereby, temperature of the bimetal (2) can be highly accurately measured using a no-contact thermometer. Furthermore, a temperature measurement part (8) of the bimetal is provided with a bending part (11), and the surface of the bending part is made to be matte black.
    Type: Grant
    Filed: April 21, 2004
    Date of Patent: March 3, 2009
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kouji Kawamura, Hiroyuki Akita, Masatoshi Murai, Hirotoshi Yonezawa, Satoru Naito
  • Patent number: 6958671
    Abstract: The present invention provides an electrical contactor for connecting and disconnecting an electrical power source to an electrical device wherein the electrical power source is electrically connected to a line terminal having a line terminal electrical contact and the electrical device is electrically connected to a load terminal electrical contact. The electrical contactor contains a plurality of electrical contacts which contact the line and load terminal electrical contacts.
    Type: Grant
    Filed: November 15, 2001
    Date of Patent: October 25, 2005
    Assignee: Square D Company
    Inventors: William Weizhong Chen, R. Kent Crawford
  • Patent number: 6873514
    Abstract: An integrated solenoid system including a single housing containing a solenoid, a controller and one or more electrical connections. The controller includes temperature compensating means and/or voltage compensating means thereby providing predetermined, substantially constant currents to said solenoid. The housing includes an integral two-part end cover.
    Type: Grant
    Filed: June 5, 2002
    Date of Patent: March 29, 2005
    Assignee: Trombetta, LLC
    Inventors: Dennis A. Maller, Todd McMahon
  • Patent number: 6700767
    Abstract: Temperature-based cooling fan control structure mainly including a thermistor for measuring ambient temperature, a voltage amplification system to indicate voltage needed for the cooling fan to rotate under the measured temperature, a magnetic induction system, a rotating speed control system for adjusting the fan rotating speed, a timing trigger capacitor periodically actuating the cooling fan to rotate when the fan is temporarily stopped under an external force, a rectification system protecting all elements in the control structure against damage due to extreme changes in voltage and current, and a voltage-stabilizing control system reducing electromagnetic noise produced in the magnetic induction system.
    Type: Grant
    Filed: April 28, 2000
    Date of Patent: March 2, 2004
    Assignee: Taiwan Da-Long Industrial CO, Ltd.
    Inventor: Nien-Lun Li
  • Patent number: 6639992
    Abstract: A speaker diaphragm is supported in a frame and a voice coil is secured to the speaker diaphragm. A rotor having a central permanent magnet and a cylindrical hub provided around the central permanent magnet is rotatably supported in the frame. A motor annular permanent magnet is disposed around the rotor. The voice coil is disposed in the gap formed between the central permanent magnet and the hub.
    Type: Grant
    Filed: November 19, 2001
    Date of Patent: October 28, 2003
    Assignee: Citizen Electronics Co., Ltd.
    Inventors: Takashi Kobayashi, Akira Nikaido, Kenshi Aihara
  • Publication number: 20020125547
    Abstract: An inductor obtained by laminating a plurality of ceramic layers having an internal coil conductor, and a thermistor obtained by laminating a plurality of ceramic layers having internal electrodes and having a predetermined resistance-temperature characteristic are laminated via an intermediate insulating layer. Both ends of the internal coil conductor of the inductor and the internal electrodes of the thermistor are connected to a pair of external electrodes. Thus, the inductor and the thermistor are connected in parallel.
    Type: Application
    Filed: March 6, 2002
    Publication date: September 12, 2002
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Masahiko Kawase, Hidenobu Kimoto
  • Publication number: 20020080548
    Abstract: In the hinge connector used for an electronic equipment, a first housing has a first hinge connector portion 75 in a hinge unit 27, and a second housing a second hinge connector portion 77 in the hinge unit 27. The second hinge connector portion 77 is housed in the hinge unit 27 slidably between a position in which the hinge connector portion is housed in the hinge unit 27 and a position in which the hinge connector portion projects out from the hinge unit 27, the first housing and second housing being mechanically combined together, the first and second hinge connector portions being then connected together by slidingly moving the second hinge connector portion in the direction crossing the mentioned combining direction at right angles thereto, the first housing and second housing being thereby electrically connected together. This structure enables a hinge connector capable of preventing damage to the connector portions, i.e.
    Type: Application
    Filed: December 19, 2001
    Publication date: June 27, 2002
    Inventors: Nobukazu Kato, Kazuhito Hisamatsu
  • Patent number: 6356424
    Abstract: An electrical protection system on a power distribution side includes a control element of a series combination of a PTC device thermally coupled with a resistive device, and a relay coil coupled with relay contacts. If the relay contacts are open the only way in which they can be closed is by supplying current to the relay coil through a resistance-capacitance network. An electronic control module on a control side includes an electronic control module for monitoring a voltage present in the system, and a switch for opening a current path feeding the system upon detection of a fault condition. An indicator indicates presence of a sensed fault condition.
    Type: Grant
    Filed: March 23, 1999
    Date of Patent: March 12, 2002
    Assignee: Tyco Electronics Corporation
    Inventors: Inho Myong, William T. Presley
  • Patent number: 6249434
    Abstract: A system and method for conducting heat from electrical devices mounted on a circuit board is disclosed. A heat sink for conducting the heat is provided that includes a pair of substantially parallel vertical legs and a horizontal member coupled between the pair of substantially parallel vertical legs to form a “U” shape. The horizontal member includes an outer surface and an inner surface both having a layer of thermal interface material. The heat sink is surface mountable to a heat sink mounting pad on a surface of a printed circuit board. The heat sink mounting pad is adjacent to and thermally coupled to a heat transfer pad of an electronic device. The heat sink is thermally coupled to the electronic device.
    Type: Grant
    Filed: June 20, 2000
    Date of Patent: June 19, 2001
    Assignee: ADC Telecommunications, Inc.
    Inventor: Christopher J. Scafidi
  • Patent number: 6127650
    Abstract: A welder has an electromagnetic switch for turning on and off the power to be supplied to the welder, a control circuit for controlling the turn on and off of this switch according to a starter signal that starts the welder and self-holding circuit for self-holding the switch. This self-holding circuit releases the switch from the self-holding when a voltage of the control circuit lowers to not more than a turn-on voltage of the switch. Therefore, when an applied voltage decreases too low to maintain the turn-on status, the switch is released from its self-holding. A voltage can thus never be applied again to the control circuit unless the starter signal is once turned off. As a result, a coil of the switch is completely free from being burnt out. Also current can be cut off when a temperature of the coil of the switch rises to not less than a given value. Therefore, if an abnormal temperature of the coil is sensed, the coil current is cut off.
    Type: Grant
    Filed: November 20, 1998
    Date of Patent: October 3, 2000
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masafumi Naruto, Yoshimichi Yasuhara, Masayuki Okubo
  • Patent number: 6072679
    Abstract: An electrical protection system includes a control element of a series combination of a PTC device thermally coupled with a resistive device, and a relay coil coupled with relay contacts. If the relay contacts are open the only way in which they can be closed is by supplying current to the relay coil through a resistance-capacitance network. A diode permits current to pass through the resistance-capacitance network to the relay coil but prevents current from flowing in the opposite direction thereby preventing relay contact chatter, contact fusing, and potential relay catastrophic failure.
    Type: Grant
    Filed: March 23, 1999
    Date of Patent: June 6, 2000
    Inventor: Inho Myong
  • Patent number: 5962978
    Abstract: An automatic degaussing circuit for a color picture tube (CPT) capable of automatically degaussing the CPT when a power conservation mode is released in a monitor having a power conservation function. The degaussing circuit includes a degaussing coil for eliminating electromagnetic waves produced from the CPT, a power conservation mode detecting section for detecting the release of the power conservation mode in accordance with a power conservation mode signal of the CPT inputted thereto and providing a degaussing control signal for controlling the operation of the degaussing coil if the release of the power conservation mode is detected, and a degaussing coil driving section for driving the degaussing coil for a predetermined time in accordance with the degaussing control signal when the power conservation mode is released.
    Type: Grant
    Filed: October 3, 1997
    Date of Patent: October 5, 1999
    Assignee: LG Electronics Inc.
    Inventor: Kwang Ho Lee
  • Patent number: 5886860
    Abstract: A Positive Temperature Coefficient Resistivity (PTC) element has a resistivity that increases as the temperature increases. Circuit breakers having PTC elements can achieve better overload and short circuit protection than existing products. Breakers with PTC elements can also be combined with ground fault detection circuits to activate the circuit breaker under ground fault conditions that are less severe than the overcurrent conditions that would normally activate the circuit breaker. A shunt trip assembly incorporating a PTC resistor reduces the required power rating of the clearing switch.
    Type: Grant
    Filed: August 25, 1997
    Date of Patent: March 23, 1999
    Assignee: Square D Company
    Inventors: William Weizhong Chen, Colin Cornhill, Andy Haun, Gary Scott, Manzoor Ali, William Rezac, Kevin James Green
  • Patent number: 5844209
    Abstract: Apparatus for control of cooking foods temperature by sensing their temperature with thermistors, which form part of a first electrical circuit that induces a magnetic flux in an electromagnet, a second electrical circuit that induces, in the electromagnet, a flux of opposite direction to the former, the resultant flux (larger flux minus smaller flux) generating a magnetic pull on the electromagnet's armature.The armature is linked to an on/off switch that forms part of a third electrical circuit that contains an alarm.Spring actuated forces on the armature oppose the magnetic pull. Increase in food temperature brings an increase of current intensity in the first circuit, which causes the magnetic pull to decrease.At the pre-selected controlled temperature of the food, the magnetic pull is slightly smaller than the opposed springs forces. At this point the armature separates from the core, putting the third circuit's switch on and activating the alarm.
    Type: Grant
    Filed: February 9, 1998
    Date of Patent: December 1, 1998
    Inventor: Arnold Gunther
  • Patent number: 5790355
    Abstract: An electric appliance control system is provided for use with an electric power unit such as an electric lawn mower. The electric appliance control system includes a battery, a selectively operable switch, a relay having first and second contacts, a control means, a charger circuit and an operator presence switch. The relay is operable by the switch to connect the electric power unit to the battery. The first and second contacts of the relay pass amperage therethrough between the battery and the electric power unit. The first contact is normally open and the second contact is normally closed. The control means includes a negative temperature coefficient thermistor in series with the first contact and multiple thermistors arranged in parallel and utilized in series with the second contact. The negative temperature coefficient thermistor variably increases the amperage passing through the first contact of the relay upon the selective operation of the switch to connect the electric power unit to the battery.
    Type: Grant
    Filed: January 22, 1996
    Date of Patent: August 4, 1998
    Assignee: MTD Products Inc.
    Inventor: William Ishmael
  • Patent number: 5722632
    Abstract: An exhaust gas recirculation (EGR) system (10) includes a proportional solenoid valve (28) that regulates vacuum pressure to a vacuum-actuated EGR valve (12). The proportional solenoid valve (28) includes an inductive coil (30) that generates a magnetic field when energized. An electronic control unit (26) energizes the coil (30) with a fixed-frequency pulse-width modulated signal. The periodic magnetic field drives a ferromagnetic armature valve (44) open and closed--alternately admitting then closing-off a flow of. atmospheric-pressure air that is used to alter the vacuum pressure output to the EGR valve (12). The vacuum pressure is dependent upon the amount of current flowing through the coil (30) during each pulse.
    Type: Grant
    Filed: April 20, 1995
    Date of Patent: March 3, 1998
    Assignee: Borg-Warner Automotive, Inc.
    Inventors: Richard K. Rader, James David Warren
  • Patent number: 5241448
    Abstract: A demagnetizing circuit for a color picture tube includes a parallel combination of a relay coil and a negative temperature coefficient (NTC) resistor in series with the primary of the power supply transformer. The contact of the relay is connected into the degaussing circuit. As the NTC warms up the current through it increases and the current through the relay coil correspondingly decreases. When the current through the relay coil falls below the relay holding current the relay contact opens and the demagnetizing current ceases to flow.
    Type: Grant
    Filed: November 12, 1991
    Date of Patent: August 31, 1993
    Assignee: Deutsche Thomson-Brandt GmbH
    Inventor: Johannes Stolte
  • Patent number: 5128826
    Abstract: In a d.c. solenoid in which a thermistor having a positive temperature coefficient is connected in series with a main coil, a subcoil is connected in parallel with the series connection of the main coil and the thermistor, so that a large magnetic force can be produced at the solenoid energization starting time, and generation of heat from the thermistor can be suppressed to prevent burn-out of the main coil due to continuous current supply. Both the main coil and the subcoil, when energized alone, are capable of actuating the solenoid. The d.c. solenoid is applied to a valve in a vaporized fuel absorption system.
    Type: Grant
    Filed: December 13, 1989
    Date of Patent: July 7, 1992
    Assignee: Aisan Kogyo Kabushiki Kaisha
    Inventor: Kazuhiro Yoneshige
  • Patent number: 4991054
    Abstract: An optical lighting control, such as that used to control street lamps, delays the response of the lamps to changes of illumination while the lamps are on at night but avoids the delay in response to daylight. Thus, headlamps, flashlights, and lightning flashes of brief duration do not cause the control to turn off the street lamps. However, the street lights turn off without this delay in response to daylight.
    Type: Grant
    Filed: May 13, 1988
    Date of Patent: February 5, 1991
    Assignee: Pacific Scientific Company
    Inventor: Jeff Walters
  • Patent number: 4860158
    Abstract: A low pressure metering pump having a hollow piston reciprocated in a cylindrical guide by a solenoid coil. A pair of check valves provide for unidirectional fluid flow through the cylindrical guide in response to the reciprocation of the piston. A seal attached to the piston prohibits a fluid backflow between the external surface of the piston and the internal surface of the cylindrical guide. A bumper seal at the output end of the piston prevents fluid flow through the cylindrical guide when the solenoid coil is de-energized. A control circuit periodically energizes the solenoid coil at a frequency determined by a variable resistance responsive to predetermined operational parameters. In a preferred embodiment, the metering pump is a fuel control element for a heater and the variable resistance is a thermistor or similar type of temperature sensitive resistance, which controls the rate at which fuel is delivered to the heater.
    Type: Grant
    Filed: October 11, 1988
    Date of Patent: August 22, 1989
    Assignee: Facet Enterprises, Inc.
    Inventor: Ralph V. Brown
  • Patent number: 4832583
    Abstract: A low pressure metering pump having a hollow piston reciprocated in a cylindrical guide by a solenoid coil. A pair of check valves provide for unidirectional fluid flow through the cylindrical guide in response to the reciprocation of the piston. A seal attached to the piston prohibits a fluid backflow between the external surface of the piston and the internal surface of the cylindrical guide. A bumper seal at the output end of the piston prevents fluid flow through the cylindrical guide when the solenoid coil is de-energized. A control circuit periodically energizes the solenoid coil at a frequency determined by a variable resistance responsive to predetermined operational parameters. In a preferred embodiment, the metering pump is a fuel control element for a heater and the variable resistance is a thermistor or similar type of temperature sensitive resistance, which controls the rate at which fuel is delivered to the heater.
    Type: Grant
    Filed: October 11, 1988
    Date of Patent: May 23, 1989
    Assignee: Facet Enterprises, Inc.
    Inventor: Ralph V. Brown
  • Patent number: 4800292
    Abstract: A temperature sensing circuit including a temperature sensing element located at a medium to sense the temperature of the medium. The sensing element is a resistive element with a range of resistive values corresponding to a range of sensed temperatures. The sensing element is connected to circuitry for detecting variations of the resistance of the element. The circuitry provides an output signal of one state when the element resistance increases beyond a first value and provides an output signal of a second state when the element resistance decreases beyond a second value.
    Type: Grant
    Filed: June 24, 1987
    Date of Patent: January 24, 1989
    Assignee: Ranco Incorporated
    Inventor: Jimmie D. Gillett
  • Patent number: 4794948
    Abstract: A solenoid operated directional control valve includes a visual position indicator assembled of rectifying bridge circuit whose DC output terminals are bridged by a series connection of a light emitting diode with a PTC resistor. In this manner, the indicator is universally applicable both for DC and AC power sources and for a wide range of supply voltages.
    Type: Grant
    Filed: December 10, 1987
    Date of Patent: January 3, 1989
    Assignee: Robert Bosch GmbH
    Inventor: Roland Schempp
  • Patent number: 4747009
    Abstract: An air conditioner clutch control device includes a resistive type temperature sensor, connected to power dividers for providing a threshold voltage and a trigger voltage for first and second comparators. Resistor type power dividers provide first and second reference voltages to the comparators. Logic circuits are attached to the comparators for providing first and second state signals. Thus, when the temperature exceeds the first reference the first state is produced to turn on the air conditioner; when the temperature falls below the second reference, the second state is produced to turn off the air conditioner. A zener diode is provided to protect the logic circuits from transients in the battery source of power and from a reversal in polarity. A coil of a relay switch is operated by the first and second states to close a switch to energize a coil of a relay switch of an air conditioner's compressor.
    Type: Grant
    Filed: April 7, 1986
    Date of Patent: May 24, 1988
    Assignee: Ranco Electronics Division
    Inventors: Jimmie D. Gillett, Richard R. Garcia
  • Patent number: 4724504
    Abstract: An electrical equipment controller is provided with a delayed turn-off capability. A thermostat is in series with a control relay. The thermostat is further in parallel with the series combination of a relay latch contact and a first positive temperature coefficient (PTC) device. A second PTC device is connected in parallel with the control relay. The arrangement of first and second PTC devices provides a predeterminable drop-out relay including compensation for ambient temperature changes.
    Type: Grant
    Filed: December 22, 1986
    Date of Patent: February 9, 1988
    Assignee: Hamilton Standard Controls, Inc.
    Inventor: Robert E. Prouty
  • Patent number: 4638784
    Abstract: In controlling a vacuum modulating valve for EGR control, incorporating therein a temperature detecting element, a required drive signal of the vacuum modulating valve, which is obtained in accordance with operating conditions of an engine including an engine speed and an engine load is two-dimensionally corrected in accordance with at least a temperature of the vacuum modulating valve, which is detected by the temperature detecting element, and a driving level of the required drive signal, so that temperature compensation with high accuracy is performed with no use of a current feedback circuit.
    Type: Grant
    Filed: July 12, 1985
    Date of Patent: January 27, 1987
    Assignee: Toyota Jidosha Kabushiki Kaisha
    Inventor: Shinji Ikeda
  • Patent number: 4623798
    Abstract: A thermosensitive switching circuit includes a first voltage divider for producing a reference voltage with a predetermined constant level and a second voltage divider for producing a detection voltage signal whose level changes in response to changes in the temperature to be detected. The reference voltage is compared with the detection voltage signal by a voltage comparator having an open-collector type output circuit, and a feedback resistor is connected between the output terminal and the input terminal of the voltage compartor to provide hysteresis for the comparing operation of the voltage comparator.
    Type: Grant
    Filed: August 13, 1982
    Date of Patent: November 18, 1986
    Assignee: Diesel Kiki Co., Ltd.
    Inventors: Kenji Arai, Kazumasa Kurihara
  • Patent number: 4452191
    Abstract: A short duration timer for use in an electronic circuit such as a diesel engine glow plug control includes a first PTC resistor energized by an electric power source and stabilized in the exponential portion of its resistance-temperature curve. A second PTC resistor in thermal contact with the first is energized at time zero from the electric power source and substantially immediately stabilizes at a temperature higher than that of the first, resulting in heat flow from the second PTC resistor to the first, and therefore an increase in the resistance of the first, at a rate which is substantially independent of variations in ambient temperature and supply voltage of the electric power source. A signal ending the time duration is generated when the resistance of the first PTC resistor has changed by a predetermined percentage.
    Type: Grant
    Filed: September 9, 1982
    Date of Patent: June 5, 1984
    Assignee: General Motors Corporation
    Inventor: Robert E. Steele
  • Patent number: 4444160
    Abstract: An indicating lamp and a PTC thermistor are connected in series across an electric power source by an ignition switch which simultaneously actuates apparatus to intermittently energize a diesel engine glow plug. Further apparatus is effective to make and break a low resistance shunt path around the indicating lamp in response to deenergization and energization of the glow plug. The indicating lamp and PTC thermistor both are electrically energized to self heat and both have electrical resistances increasing sufficiently with temperature to drop substantially most of the supply voltage when hot and prevent energization of the cold other. The indicating lamp heats much faster than the PTC thermistor and so energizes during the initial energization of the glow plug to signal the vehicle operator to not attempt starting of the engine.
    Type: Grant
    Filed: September 9, 1982
    Date of Patent: April 24, 1984
    Assignee: General Motors Corporation
    Inventor: Robert E. Steele
  • Patent number: 4321447
    Abstract: An energization circuit for a microwave oven employs a PTC thermistor to eliminate high transient current surges resulting from energization and deenergization of induction elements therein to provide circuit protection both during oven start and operation. The energization circuit comprises first and second parallel circuit portions for energizing a transformer used to energize a magnetron that produces microwave energy, the first circuit portion including a normally open start switch and a current limiting PTC thermistor coupled in series relation and the second circuit portion including a relay operated switch, a relay for operating the relay operated switch, and a relay circuit portion connected to the first circuit portion between the start switch and PTC thermistor for energizing the relay upon closure of the start switch and then through the PTC thermistor upon opening of the start switch.
    Type: Grant
    Filed: August 7, 1980
    Date of Patent: March 23, 1982
    Assignee: The Tappan Company
    Inventor: John T. Lamb
  • Patent number: 4320309
    Abstract: A control circuit for producing a repetitive closed-circuit, open-circuit condition between an electrical power source, such as a battery, and an electrical load comprises a positive temperature coefficient resistor in series with a relay coil. The PTC resistor is caused to alternate between a low resistance state and a high resistance state which permits energization and de-energization of the relay coil.
    Type: Grant
    Filed: December 31, 1979
    Date of Patent: March 16, 1982
    Assignee: GTE Products Corporation
    Inventors: Charles R. Griffiths, William G. Ferguson
  • Patent number: 4234904
    Abstract: A process for the protection of electrical systems upon return of power after power interruptions, through the immediate disconnection of secondary consuming units by an audio-frequency control receiver, and the subsequent reconnection thereof in timed sequence. The audio-frequency control receivers have, in addition to a normal control path, a second path, through which, upon return of the voltage, the switch relay for secondary consuming units is disconnected upon reaching 2/3 of the system voltage. The process may be implemented through the use of a two-state D.C. relay, which is controlled by a secondary path including a cold lead to the system voltage. The process may alternatively be implemented through the use of a two-state A.C. relay which is controlled through a half-wave secondary path including a capacitor/resistor parallel circuit.
    Type: Grant
    Filed: July 18, 1979
    Date of Patent: November 18, 1980
    Assignee: LGZ Landis & Gyr Zug AG
    Inventor: Kjell T. Fahlesson
  • Patent number: 4219861
    Abstract: A protector means is provided to prevent thermal destruction of a solenoid adapted for very short duration energization at currents far in excess of the continuous current carrying capability of the solenoid. The protector means includes a positive temperature coefficient thermistor which controls the gate potential of an S.C.R. whose power circuit is in series with the solenoid. When thermistor temperature rises to a predetermined level the voltage applied to the gate drops below the gate threshold thereby preventing the S.C.R. from firing on the next positive half-cycle.
    Type: Grant
    Filed: November 27, 1978
    Date of Patent: August 26, 1980
    Assignee: Gould Inc.
    Inventor: Henry Wiegand
  • Patent number: 4104692
    Abstract: A device for detecting an abnormal temperature in a fixer, including a pulse generation controller capable of detecting the temperature in the fixer, comparing it with a predetermined reference temperature, and generating pulses continuously while the fixer temperature is lower than the reference temperature or generating no pulse at any other time; a pulse interrupter for interrupting the pulse output from the pulse generation controller until the temperature in the fixer reaches a desired fixing temperature for the first time after the start of power supply to the fixer, and an abnormality detector for detecting an abnormal fixing temperature when the integral of the pulses having passed through the pulse interrupter within a given time has reached a predetermined value.
    Type: Grant
    Filed: January 3, 1977
    Date of Patent: August 1, 1978
    Assignee: Rank Xerox, Ltd.
    Inventors: Katsumi Sudo, Yukio Kanazawa
  • Patent number: 4060123
    Abstract: An improved energy saving control apparatus particularly designed for providing energy saving control of individual room heating and cooling units in direct response to the active occupancy status of the room. Switching means selectively interrupt energization of the load element of a room heating/cooling unit in response to an interrupt control signal. An electronic energy saving control circuit responds to changes in the ambient air room temperature and overrides the heating/cooling unit thermostat to selectively generate the interrupt control signal for maintaining the ambient air room temperature within a broad predetermined and pre-settable energy saving temperature range whenever the room is not actively occupied. Occupancy status detector means, including a uniquely detectable and detachable member typically carried by the room occupant and cooperative detector means within the room provides a real time indication of the active occupancy status of the room.
    Type: Grant
    Filed: September 27, 1976
    Date of Patent: November 29, 1977
    Assignee: Fabri-Tek Incorporated
    Inventors: Gerald F. Hoffman, Dewayne P. Bolton
  • Patent number: 4055296
    Abstract: An electronic temperature control system utilizes a circuit having two main terminals for connection to a low voltage relay control system of the type generally used in residential heating or cooling systems without the need for an auxiliary source of power. The circuit includes a temperature sensing thermistor, an adjustable reference voltage control, a programmable unijunction transistor voltage threshold detector circuit, power switching thyristor means and bridge diodes. Heat anticipation is provided by thermally coupling the thyristor switching means and the temperature sensing thermistor.
    Type: Grant
    Filed: March 25, 1976
    Date of Patent: October 25, 1977
    Inventor: Robert J. Buck
  • Patent number: RE31502
    Abstract: A control system for energizing and de-energizing an external load in series with a source of electricity incorporates a rectifying network having inputs in series with the alternating current source and the external load. An electronic switch of the system activates the load by effectively shorting together the inputs to the control system when the combination of externally sensed parameters obtain predetermined magnitudes. The sensed parameters control the activation of the electronic switch by a plurality of control modules which interact with a control logic module, representing a Boolean combination of the control module outputs, so as to activate a trigger module which in turn causes the electronic switch, such as a silicon controlled rectifier (SCR) to be triggered. The external load is then energized by the SCR effectively shorting the inputs to the control system and which thus completes the electrical path from the source of electricity through the load.
    Type: Grant
    Filed: August 10, 1978
    Date of Patent: January 17, 1984
    Inventor: Richard P. Gingras