Abstract: A security gate operating system, is disclosed which comprises an electrically powered motor; a thermally controlled circuit breaker set to remove power to the motor when the motor reaches a preselected threshold temperature; a cooling fan associated with the motor and selectively powered to provide auxiliary cooling to the motor to prevent the motor from overheating; and a cooling fan motor controller, adapted to selectively supply power to the cooling fan when the motor is approaching the threshold temperature. The apparatus can further comprise the cooling fan controller being a thermo-static switch set to close at a preselected temperature below the threshold temperature, or a programmed microprocessor/microcontroller programmed to provide power to the cooling fan at a preselected temperature below the threshold temperature or when the temperature of the motor is about to reach the preselected temperature.

Abstract: A thermal protection apparatus for an AC traction motor including a stator, a rotor, a blower fan and an inverter includes a method and apparatus for predicting the motor temperature assuming that the blower is operational. The method and apparatus also determines an estimated motor temperature by measuring the motor resistance or the rotor slip. The estimated motor temperatures compared to the predicted motor temperature to determine the condition of the motor cooling system.

Abstract: An electric steering lock apparatus that protects an actuator from overheating without enlarging the actuator. The electric steering lock apparatus includes a lock pin engaged with a steering shaft to lock the steering shaft. An actuator moves the lock pin between a lock position in which the lock pin is engaged with the steering shaft and an unlock position in which the lock pin is disengaged from the steering shaft. A control unit controls the actuator. The control unit generates a calculated value related to operation time of the actuator and suspends operation of the actuator when the calculated value is greater than a predetermined operation suspension threshold value.

Abstract: In order to determine the temperature in the winding region of an electric motor, especially linear motor, a measuring line made of uniform; electrically conductive material is integrated in a winding, preferably in sections between winding teeth. The measuring line may be configured as insulated double line which is short-circuited on one side. A change in the resistance value of the measuring line allows conclusion about a temperature change and is easy to ascertain.

Abstract: A over heat protection circuit for a brushless dc motor includes a thermal sensitive resistor, a resistor and a transistor. The thermal sensitive resistor and the resistor are commonly connected to a base of the transistor while an emitter of the transistor connecting to a motor coil. The thermal sensitive resistor has a resistance value which can be changed in response to an operational temperature. The thermal sensitive resistor is preset to operate at a safety temperature within a predetermined thermal preference. When the operational temperature of the motor coil exceeds the safety temperature, the over heat protection circuit may to cut off a motor current so that the motor coil is protected.

Abstract: A solid state motor protector has a first PTC chip (positive temperature coefficient of resistivity) electrically connected in series relation with a second resistor having a generally fixed temperature coefficient of resistivity and mechanically coupled to the first resistor in close thermal coupling. In a first embodiment, a polymer PTC resistor (12) and fixed resistor (14) are stacked together along with a spring member (22) and received in an open ended isolator (16) with terminal plates disposed respectively on the top and bottom of the isolator to load the spring and electrically connect the stack. A second embodiment has the sidewall of a cup-shaped terminal (32a) insert molded in the isolator (32) with another cup-shaped terminal received on and clamped to the isolator. A third embodiment has a plate like isolator (52) formed with an opening receiving a polymer PTC chip (58) and having terminals (54, 56) which serve as fixed resistors.

Abstract: A fault detection system detecting malfunctions or deteriorations, which may result in an inverter fault, is provided. The system has a temperature sensor installed on a semiconductor module to monitor a temperature rise rate. It is judged that an abnormal condition has occurred if the thermal resistance is increased by the deterioration of a soldering layer of the semiconductor module or by drive circuit malfunctions and, as a result, the relation between an operation mode and the temperature rise rate falls outside a predetermined range.

Abstract: A thermally suppressing circuit mainly comprises a restart-charging drive member, a coil set, a restart-charging capacitor, and a charging switch set. The restart-charging drive member is electrically connected to the coil set and the restart-charging capacitor while the charging switch set connected between the coil set and the restart-charging capacitor. The charging switch set is used to access signals output from the restart-charging drive member. In abnormal operation, as the restart-charging drive member may turn on an auto-restart function to output a high or low voltage signal, the charging switch set is turned on to accelerate charging the restart-charging capacitor to thereby avoid overcurrent passing the coil set.

Abstract: A motor control device having temperature protection function comprises a motor drive module and a temperature detection and control module. The motor drive module comprises a driver, a magnetic field detector, and a voltage regulator. The driver is used to drive a motor. The magnetic field detector is used to detect a magnetic field variation signal of the motor. The temperature detection and control module comprises a temperature sensor and a hysteresis switch, and is used to detect the temperature of the motor for controlling disconnection and restart of the motor according to the temperature value. The voltage regulator is connected to an external power source, and is used to provide a stable voltage to the whole motor control device. Thereby, the advantages of simple design, low cost, and prevention of over heat of motor can be achieved.

Abstract: A vehicle power system includes a multiple of electrical generators which provide power for vehicle electrical systems or loads through an electrical load management center which communicates with a general purpose processor set such that the power supplied to each electrical load may be individually controlled. A display communicates with the GPPS to present an electrical system status screen to the vehicle crew such that the crew is constantly made aware of the prevailing electrical power conditions in a rapid and efficient manner. During a drastically reduced generator situation, the GPPS automatically disconnects loads via a predefined load shed priority list. Once electrical loads are disconnected via the predefined load shed priority list the crew can reactivate and deactivate selected systems for the current mission circumstances through a load recovery screen accessible through the display.

Abstract: A circuit disconnecting member that blows on receiving radiant heat generated by heat generation of a motor circuit is connected to a motor circuit, the blowing temperature being a temperature lower than a thermal breakdown temperature of a combustible substance around the motor circuit, whereby the motor circuit is shut off, when the peripheral part of the motor circuit generates heat, to stop heat generation before an insulation cover or a contact case is subjected to thermal connection breakage. An engine starting device is prevented from being subjected to a thermal breakdown by a small-size, simple construction and an inexpensive technique without impairing the mounting layout properties of the starting motor and the performance within the rated use.

Abstract: A sensor holding member made of elastically deformable material is mounted to a bracket that covers a stator winding. In addition, a sensor for stator winding overheat protection is attached to a tip of the sensor holding member. The bracket, the sensor holding member, and the sensor are formed into a one-body structure. When the bracket is mounted to the stator, the sensor holding member is contracted under force caused by the sensor pressed against the stator winding. As a result, the sensor is pressed against the stator winding by elastic repulsive force of the sensor holding member.

Abstract: A protector assembly and method for protecting motor windings from an overload condition. The assembly comprises a thermally responsive protector, a skirt, and a sleeve. The protector comprises a housing, an end cap, at least one terminal, and a thermally responsive member. The end cap covers an open end of the housing. The terminal extends through the end cap. The thermally responsive member is within the housing and adapted to be electrically coupled to the motor winding via the terminal. The protector is adapted to be positioned in heat-transfer relation wit the motor winding in a manner such that the thermally responsive member is responsive to an overload condition of the motor winding. The skirt and sleeve are of dielectric materials. The skirt is positioned on the protector in a manner such that the skirt surrounds the end cap and the terminal. The skirt is between the end cap and the sleeve.

Abstract: A method and an apparatus for protecting an engine starter of a motor vehicle against overheating with enhanced reliability by controlling turn-on/off of the starter in dependence on a conducting current of the starter, a starter temperature and an ambient temperature. The apparatus includes a voltage detecting means (1) for measuring a supply voltage (Vs) of the engine starter, a voltage waveform information detecting means (11) for detecting at least one of frequency information and amplitude information of a waveform representing variation of the supply voltage (Vs) as voltage waveform information (T), and a conduction time control means (12, 12A) for controlling a conduction time period of the engine starter in accordance with the voltage waveform information (T).

Abstract: A system for motor thermal protector device performance test data collection includes a microprocessor configured to measure elapsed times of reset and trip power cycles of a motor winding through a thermal protector device. An operator interface terminal is coupled to the microprocessor and includes a display and input selectors for recalling a predetermined number of elapsed reset and trip times stored in a system memory.

Abstract: A method for monitoring the health of power electronics includes: providing a switch command to a power electronic device (12) through a gate driver (14); measuring a switching time of the power electronic device; and using the switching time to determine a diagnostic condition of the power electronic device and/or the gate driver.

Abstract: A motor driving control device that achieves as high as possible phase coil energization level while preventing thermal destruction of the power switching element by using precise thermal detection of a portion of the power switching element inside a switching module of the control device. An electric power loss Lt at the switching element is used for calculating a saturation temperature Tjgoal. On the basis of the saturation temperature, Tjgoal, and a time constant &tgr; of temperature rise, an instant junction temperature Tjnow is calculated. A difference Error between the instant junction temperature Tjnow and an upper temperature limit value Tjmax is calculated. In a motor locked condition, a coefficient Kt is calculated for the target torque, the target torque being equal to the required torque multiplied by Kt. Kt is based on the Error for calculating the target torque. If Error is greater than or equal to a predetermined value, K3, Kt is set to be 1, even if Kt is in excess of 1.

Abstract: The thermal load of an electrical component is used as a basis to limit an electric current through the electrical component, in particular the rotor winding of a turbogenerator. This reliably avoids overheating of the component and at the same time achieves full exhaustion of the electric current, particularly in the case of field forcing.

Abstract: A vehicle electric assist steering system (10) includes a switching circuit (56) for providing electrical power to an electric motor (52) of the vehicle steering system. The switching circuit (56) has a temperature condition. A temperature sensor (69) is coupled with the switching circuit (56) for providing an output signal (71) having a value indicative of the temperature condition of the switching circuit (56). A stall detector (70) is responsive to the output signal (71). The stall detector (70) is operable to reduce power to the electric motor to different level during a stall condition based on the sensed temperature condition of the switching circuit (56).

Abstract: A circuit disconnecting member that blows on receiving radiant heat generated by heat generation of a motor circuit is connected to a motor circuit, the blowing temperature being a temperature lower than a thermal breakdown temperature of a combustible substance around the motor circuit, whereby the motor circuit is shut off, when the peripheral part of the motor circuit generates heat, to stop heat generation before an insulation cover or a contact case is subjected to thermal connection breakage. An engine starting device is prevented from being subjected to a thermal breakdown by a small-size, simple construction and an inexpensive technique without impairing the mounting layout properties of the starting motor and the performance within the rated use.

Abstract: A two stage reciprocating compressor and associated HVAC systems and methods are disclosed. The reciprocating compressor includes a crankshaft having an eccentric crankpin, a reversible motor for rotating the crankshaft in a forward and a reverse direction, and an eccentric, two position cam rotatably mounted over the crankpin. The crankshaft and cam combine to cause the piston to have a first stroke when the motor operates in the forward direction and a second stroke when the motor operates in the reverse direction. The cam and crankpin also include stabilization means to restrict the relative rotation of the cam about the crankpin. A lubrication system is provided to lubricate the engaging surfaces of the crankshaft and cam and between the cam and the bearing surface of the connecting rod. There is also provided a control for selectively operating the motor either in the forward direction at a first power load or in the reverse direction at a reduced second power load.

Abstract: A thermal switch arrangement for electromagnetic coils of electric motors, including at least one coil, which has a winding (52, 54) and a coil former (30, 48) in the form of a winding core (32), which is enclosed by two end flanges (36, 38; 56, 58, 60, 62), and flat plugs (26, 28; 74, 76, 78), which are connected with the two ends of the winding and/or the connections of a thermal switch (80), assigned to the winding, and are inserted and locked in pockets (40, 42; 64, 66) in or at at least one end flange (36, 38; 56, 58, 60, 62) from the peripheral edge of the latter and locked. Two tags (82, 84) of the thermal switch (80) enter the pockets (40, 42; 64, 66) of the flat plug (74, 78) from the inner surface of the one end flange (36, 60).

Abstract: Leg portions are provided at the four corners of a resistor that generates a large amount of heat and a partition panel is secured to the top of the leg portions through a heat-insulating spacer. A adiabatic layer is formed by an empty space between the resistor and the partition panel. Further, the transmission of heat from the resistor through the leg portions to the partition panel is suppressed by the heat-insulating spacer. A servo amplifier is connected to the mounting portions provided on the partition panel, at the side opposite the resistor main body. As the transmission of heat generated by the resistor to the servo amplifier main body is cut off by the partition panel and suppressed, components inside the servo amplifier are protected from heat.

Abstract: The electric motor drive includes an electric motor (10); an end stage (12) for triggering the electric motor; a trigger circuit (18) for pulse-width-modulated triggering of the end stage, which is associated with the end stage (12) and which includes an overload stage (20) for detecting an overload on the electrical motor according to a temperature of the electric motor and a device for obtaining a temperature from a pulse-width-modulation signal (16) generated by the trigger circuit (18). A preferred embodiment includes a device for integrating a differential power (Pdiff) equal to an instantaneous power (Pmom) minus an equipment specific limit power (Plimit) in predetermined time intervals to obtain an integrated power (Pnew). The motor is turned on or off by comparison of the integrated power with various limiting values.

Abstract: A motor starter thermal-compensation control is disclosed in which an ambient temperature sensor is positioned to sense ambient temperature and provide an ambient temperature signal in a motor starter. Additional temperature sensors are mounted in thermal communication with each bus bar in a motor starter and to monitor the temperature of each pole. A microprocessor is connected to each of the temperature sensors and periodically receives the temperature signals to monitor change in operating temperature of the motor starter. The control adjusts the output of the motor starter based on the change in the operating temperature so as to maintain a constant output as the ambient temperature increases, or the internal resistance of the device increases with temperature increase. In order to adjust the output, the system increases the FLA ampacity to compensate for the temperature increase.

Abstract: A motor starter control is disclosed in which an ambient temperature sensor is positioned to sense ambient temperature and pole temperature sensors are used to sense each pole temperature in a motor starter. A microprocessor is connected to periodically receive the temperature signals and monitor change in operating temperature of a motor starter system. The microprocessor models cool down characteristics of the motor starter system and compares currently acquired ambient and pole temperature signals to the modeled cool down characteristics and determines whether the motor starter system is cooled to a safe start temperature. The control ensures that a maximum number of starts per hour is not exceeded and prevents attempted starts that not only waste energy, but further prolong time to a successful start.

Abstract: A method (10, 30) for actively controlling the temperature (tmotor) of an electric machine operating under torque (T*), speed and/or position control. A controlled output (T*), i.e. torque command, voltage, current or power, is adjusted such that the temperature of the electric machine does not exceed a predetermined reference limit (tref). The method (10, 30) of the present invention performs proportional-integral control (14) to reduce the commanded output (T*) to the motor and thereby prevent the steady-state motor temperature (tmotor) from increasing beyond the predetermined limit (tref). In one embodiment of the method (10), an error term (e) is filtered through a negative pass filter (12) before being combined with an optional decay term (&egr;decay) in a proportional-integral controller (14). A positive pass filter (20) and a negative pass filter (22) provide outputs that are summed and provide an adjusted output command (Tlimited) based upon predetermined relationship.

Abstract: In order to control the operating voltage of a fan in electrical equipment, the temperature of an output diode (D) of an output circuit of the power supply of the electrical equipment is monitored. The operating voltage of the fan is controlled as a function of the component temperature of this physical element such that up to a limit temperature, which is in the region of the maximum permissible component temperature of a physical element which absolutely becomes the hottest, the operating voltage of the fan is regulated at a constant, minimum level. The operating voltage is then regulated to rise continuously and rapidly up to a maximum operating voltage at which, although the component temperature of the physical element which absolutely becomes the hottest is still above the limit temperature, it is below the maximum permissible component temperature of this physical element, however.

Abstract: In a motor control unit adapted to control each switching element of each switching arm and control the current sent to a motor, the temperature sensing diodes 19a˜19c are arranged near the switching elements and a constant current circuit 18 is connected to the temperature sensing diode. An overheat prevention means is also provided to recognize the switching element temperature by detecting a forward voltage value of the diode and to place the switching element in an OFF-state when the switching element is judged to be in an overheat condition based on the recognized temperature of the switching element.

Abstract: A motor start switch includes a temperature responsive resistor element and a cutout switch electrically connected in series with a start winding of an electric motor. The cutout switch is in thermal contact with the temperature responsive resistor element so that heat from the temperature responsive resistor element is transferred to a bimetal element in the cutout switch, causing the bimetal element to open the switch. Heat from a motor overload protector provides heat to maintain the bimetal element in an open position. As heat to operate the temperature responsive resistor element is obtained from existing circuit elements, the efficiency rating of the motor is unaffected.

Abstract: An electric motor includes a stator having a plurality of conductive windings radially spaced about a central axis. A rotor is located radially inward up the stator and is rotationally fixed with respect to a shaft along the central axis. The rotor and the stator are disposed in a frame. A heater is in operative communication with the windings. A thermostat is in operative communication with the heater and is configured to activate and deactivate the heater responsively to a motor temperature.

Abstract: A DC power source unit includes a main unit that generates DC voltage, and an output cable. The output cable has one end connected to the output of the main unit and another end attached to an adapter plug. The adapter plug Is electrically connected to an electrically powered tool, such as an electrical drill. Current flowing in the tool is detected every predetermined interval and accumulated electrical quantity is computed based on the detected current flowing in the tool. Based on the accumulated electrical quantity, the temperature of the tool is predicted. When it is determined that the tool is heated up to a first critical temperature based on the accumulated electrical quantity, an alarm unit is actuated. When it is determined that the tool is further heated up to a second critical temperature, supply of current to the tool is interrupted.

Abstract: An electronic motor protection system which protects electric motors against various fault conditions such as over-temperature (12) of the individual windings of the motor and low voltage (18, 20). The system has a power supply compatible with 24, 120 or 240 VAC input voltage using only two input terminals. According to a first embodiment, line voltage is inputted to a transformer (T1) while the combination of a zener follower (Z1, Z2, Q1) and series regulator (U1, Q2, Q3) provide independent DC voltage supply levels or voltage rails (VR1, VR2) for control circuitry over a wide range of input voltages. A dead-band voltage range is provided by a circuit section (20) which works in conjunction with a 240 volt, low voltage cut-out circuit section (18) to prevent the possibility of chatter in 240V motors and excessive voltage from being applied to 120 volt motors.

Abstract: A scroll pump comprising a fixed scroll, an orbiting scroll orbiting with a radius which is the same as the eccentric distance of an eccentric shaft to the center of the fixed scroll and contacting the fixed scroll, an inlet port formed in the middle of the upper side of the fixed scroll to influx incompressible hydraulic fluid into the scroll pump, a pressure chamber formed at the outside of the orbiting scroll to raise the pressure of the incompressible hydraulic fluid, and an outlet port formed at the side of the fixed scroll to discharge the incompressible hydraulic fluid from the scroll pump.

Abstract: Disclosed is a method for controlling a temperature of an electric motor. According to the present invention, the method for controlling the temperature of the electric motor includes the steps of setting a present temperature of the electric motor as an initial value, comparing the present temperature with a lower limit temperature when the multifunctional apparatus receives an order to perform a printing, performing the printing if the present temperature is lower than the lower limit temperature at the comparing step, converting a time for printing into an increased value of the temperature at the performing step and resetting the increased value of the temperature as the present temperature, and delaying the printing for a predetermined time if the present temperature is higher than the lower limit temperature at the comparing step.

Abstract: A motor starter temperature protection control in which an ambient temperature sensor is positioned on an inside cover of the motor starter to sense ambient temperature across the power poles and heat sinks and provide an ambient temperature signal indicative of the ambient temperature in the motor starter enclosure. A power pole temperature sensor is positioned in thermal communication with each power pole and produce pole temperature signals indicative of the temperature of each power pole. A microprocessor is connected to each of the temperature sensors and receives the ambient temperature and the pole temperature signals to control the motor starter operation based on the temperature inputs. The microprocessor is programmed to periodically monitor the ambient and power pole temperature signals and compare these signals against a fan-on limit, and if the signals exceed the fan-on limit, the control turns on the internal fans of the motor starter.

Abstract: A temperature sensor is located close to each of a plurality of switching elements. Each of the elements opens and closes a current supplying line from a power supply to a three phase SR motor. A generating circuit of a instruction value for the driving current of the motor generates a target value (It) of the driving current so as to achieve a requested power of the motor and an allowable value of the driving current on the basis of the highest temperature sensed by the temperature sensors. The circuit outputs the target value as an instruction value of the driving current when the target value is smaller than the allowable value and outputs the allowable value as an instruction value of the driving current when the target value is greater than the allowable value.

Abstract: A movable barrier operator includes a wall control switch module having a learn switch thereon. The switch module is connectable to a control unit positioned in a head of a garage movable barrier operator. The head unit also contains an electric motor which is connected to a transmission for opening and closing a movable barrier such as a garage door. The switch module includes a plurality of switches coupled to capacitors which, when closed, have varying charge and discharge times to enable which switch has been closed. The control unit includes an automatic force incrementing system for adjusting the maximal opening and closing force to be placed upon the movable barrier during a learn operation. Likewise, end of travel limits can also be set during a learn operation upon installation of the unit.

Abstract: Torque is distributed by calculating first and second torque commands using a requested torque and a ratio of speeds of first and second wheels and limiting them in accordance with respective torque command approved ranges and approved change rates; converting the limited torque commands to horsepower commands and limiting them in accordance with respective horsepower command approved ranges and approved change rates; and converting the limited horsepower commands to present torque commands. Maximum horsepower available is determined by using an engine speed to determine a nominal amount of available horsepower; applying a desired load status signal and an actual engine load status signal to a proportional-integral regulator; and using the nominal amount of available horsepower and an output signal of the regulator to determine the maximum amount of available horsepower.

Abstract: Backward movement of a heavy motorcycle is assisted by a starter motor for cranking an engine of the motorcycle. A backward drive control system includes a pulse width modulation circuit for supplying operating current to the starter motor in a controlled manner and a device for estimating operating temperature of the starter motor based on the current supplied to the starter motor. When the estimated temperature reaches a predetermined maximum temperature, the operation of the starter motor is compulsorily stopped and prohibited for a certain period or until the starter motor is cooled down to a certain temperature level. Overheating of the starter motor is effectively prevented without using a temperature sensor for measuring the operating temperature.Moreover, chattering of the starter motor does not occur because its operation is prohibited for a certain period after the starter motor is once compulsorily stopped.

Abstract: A protective device suitable for being placed in the power supply circuit of an electric motor, having at least one anti-interference coil (20, 30) for the motor, and a thermal switch (10) thermally coupled to coil (20, 30) and capable of opening the power supply circuit when the coil temperature which it detects reaches a predetermined value, representative of the maximum temperature threshold allowed within the motor. Advantageously, the device also has an electric heating element, thermally coupled to the switch and capable of constituting a main current path between the two input terminals of a four-terminal network consisting of the protective device, when the power supply circuit is open, and capable of holding this circuit open in order to limit the opening-closing cycles of the switch, the invention also pertains to the corresponding process and to a drive device containing a motor and of said protective device mounted on the motor, outside of it.

Abstract: Rotor temperature in induction motors is estimated without the need for any direct temperature sensors, by using only computer calculations based on data readily available in the motor control center. Thus for any given motor, it is generally possible to predetermine a relationship between rotor temperature and rotor resistance, so that by determining rotor resistance, rotor temperature can be calculated. Rotor resistance, in turn, can be calculated from measured information relating motor slip and motor torque. Any of several methods can be employed for determining torque and slip. Temperature estimation can be obtained by use of equivalent circuit methods, and additional relationships can be obtained from a simplified equivalent circuit.

Abstract: An arrangement for measuring the operating temperature of an electromechanical machine utilizes at least one elongate sensor device inserted into a winding slot of the stator core. The sensor device includes a lead attachment portion at which a plurality of relatively large gauge lead wires are attached. The lead wires preferably have a length sufficient to extend to a location outside of the motor housing. The sensor device includes an elongate sensing portion having temperature sensitive conductors. Preferably, the sensing portion is located entirely within the axial extent of the stator core. An elongate transition portion having temperature insensitive conductors provides electrical connection between the lead wires and the temperature sensitive conductors of the sensing portion.

Abstract: A control device for operating a wiper motor (10) which utilizes the typical path of the wiper motor current (Im) with cyclically recurring minima during the detection of an overload of the wiper motor (10) caused by blockage or tightness of the wiper. During this process, a storage element (C) that integrates the motor current (Im) is short-circuited at least twice within a wiping cycle (Tw) during normal operation so that the transfer of the admissible overload from a half of a wiping cycle (Tw/2) to the following half of the wiping cycle (Tw/2) is prevented and the limit value (G) for the shut-down of the wiper motor (10) is not reached through accumulation of the admissible overload.

Abstract: An overheating protection system for a switching module prevents thermal breakdown of switching devices for passing currents through a load, for example an electric motor, while making it possible for the switching module to provide as much required current to the load as possible. The system comprises a temperature detector for detecting the temperature of a switching module, a temperature estimator for calculating a temperature change rate of a switching device inside the switching module corresponding to a current passed through the load and calculating an estimated value of the internal temperature of the switching module on the basis of the calculated temperature change rate and the detected temperature and a current limiter for on the basis of the estimated value correcting a target current value of a current controller controlling a current passed by the switching device.

Abstract: A motor protector (1) for use in an electrical circuit for supplying current to a motor (10) to be protected having two separate bimetallic disk actuated switches (4, 5) contained within the protector (1) electrically connected in series with each other and the current source (13) and motor (10). In one embodiment, one of the two switches (6) uses a two bimetallic disk design in which the disks have different temperature actuations and reset values for providing a fail-safe feature.

Abstract: An overheat protection circuit includes a resistor having a first lead connected to the engine temperature switch and the power take off (PTO) relay coil circuit. The second lead of the resistor is connected to the output of an interlock circuit to provide an energizing voltage signal to the PTO relay for operation of the PTO driven attachment when preselected operating conditions are present on the vehicle. If for any reason the engine temperature rises above a preselected maximum operating temperature, the engine temperature switch will close and cause the voltage at the second lead to drop below the minimum operating voltage of the PTO relay. The PTO relay deenergizes to remove drive from the attachment. The PTO cannot be reengaged until the engine operating temperature drops below the maximum operating temperature. The resistor preferably is a positive temperature coefficient thermistor to reduce power dissipation through the circuit while the temperature switch is closed and the PTO relay is deenergized.

Abstract: An apparatus is provided for controlling temperature of a motor by estimation. The temperature apparatus includes an initial setting circuit for setting an initial value of a temperature representative variable .theta., a temperature rise estimating circuit for calculating .theta.+A (where A is an incremental parameter reflecting a temperature rise under driving of the motor) for renewal of .theta. when the motor is driven, a temperature drop estimating circuit for calculating .theta.-.theta./S (where S is decremental parameter reflecting a temperature drop by heat dissipation of the motor) for renewal of .theta. periodically at a predetermined time interval while the temperature control apparatus is operating, and a power supply prevention circuit for preventing power supply to the motor when .theta. becomes no less than .theta.max (which is an upper limit parameter reflecting an upper tolerable limit temperature of the motor) and until .theta. becomes lower than .theta.max.

Abstract: A power supply apparatus includes a housing containing therein a component which generates heat when operating, a fan for cooling the heat-generating component, and a driving unit for driving the fan. The housing also contains therein a temperature detector for detecting the temperature in the housing and providing a detected-temperature representing signal. In response to the detected-temperature representing signal, a control unit provides the driving unit with a control signal to change the rotation speed of the fan.

Abstract: The present invention involves control and protection circuit for a compressor motor which includes an inductively activated contactor for controlling the flow of current to the compressor motor. The circuitry of the present invention includes a plurality of current detectors associated with each phase winding of the compressor motor for sensing the current in each phase winding. The sensed currents are combined in a predetermined manner and used to provide protection against an overcurrent condition, single phase operation and light loading condition. Additional detector circuits are also connected to the present control and protection circuit to provide protection against high temperature in the compressor motor windings, high temperature in various component of the compressor motor, and undervoltage in the power supply.