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: A ventilator having a muting device includes a central processing unit, and a fan motor. The fan motor is connected to a start capacitor which is electrically connected to a temperature sensing circuit which is electrically connected to the central processing unit, so that the start capacitor can indicate a signal on a panel of the ventilator, so as to control a rotational speed of the fan motor. Thus, the operation state of each part of the ventilator is indicated on the panel of the ventilator clearly to facilitate inspection of the user, so that the user can control the rotational speed of the fan motor to a proper value, thereby reducing the noise during operation, so as to achieve a muting effect.

Abstract: A starter circuit for motors, particularly for refrigerator compressors, comprising a starter device which is adapted to be connected to a starter winding and to a steady-state winding of an asynchronous motor, the windings being in turn connected to a power supply line, a capacitor being connected in parallel to the starter device; the starter circuit further comprises a resistive element which is adapted to be connected between the starter device and the capacitor, in order to limit a discharge current of the capacitor on the starter device.

Abstract: A motor current controller for a permanent magnet AC motor achieves a decrease in bandwidth variations that would otherwise be caused by temperature changes. The current controller dynamically modifies the integral gain of a proportional-integral regulator in response to temperature-induced changes in motor resistance. The integral gain value is calculated to maintain a substantially constant loop bandwidth within a current loop primarily comprising the permanent magnet AC motor, semiconductor switches connected in an H-bridge configuration, and the proportional-integral regulator.

Abstract: An electric power steering system is provided which assists a steering operation by applying a driving force generated by an electric motor to a steering mechanism of a motor vehicle. The system includes a sensor (e.g., a torque sensor) for acquiring information necessary for controlling the electric motor, and a board provided adjacent the electric motor and having a sensor signal processing circuit for processing a signal from the sensor. A temperature sensor for acquiring temperature information necessary for controlling the electric motor is mounted on the board.

Abstract: A starting motor for an internal combustion engine, where a control circuit monitors or controls the temperature of the starting motor or the carbon brushes, and if necessary, limits or switches off the primary current. The temperature is indirectly determined by means of a comparison, using the voltage ripple in the primary circuit between the battery and the starting motor. Occurring errors can be stored as status messages in an error storage device, and if desired, they can be interrogated and corrected at the next service interval.

Abstract: A hermetic compressor is disclosed having an electric motor, a compressor unit, and an overload protector within a hermetically sealed housing. The overload protector includes a thermally activated switching device for selectively providing current to the electric motor, a heater element thermally coupled to the switching device, and a control circuit controlling the heater element. The overload protector allows the disconnection of power to the motor due to factors and conditions specified in the remotely located control circuit.

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: A fuel cell power plant (1) and a rechargeable battery (2) are connected in parallel to an electric motor (3) of a fuel cell powered vehicle, and the output voltage of the fuel cell power plant (1) is regulated by a converter (4). A temperature sensor (5) detects the temperature of the electric motor (3), and a controller (6) controlling the output voltage of the converter (4) to a predetermined high voltage value when the temperature of the electric motor (3) is greater than a predetermined temperature, thereby preventing the excessive rise of the temperature of the electric motor (3).

Abstract: A hermetic compressor is disclosed having an electric motor, a compressor unit, and an overload protector within a hermetically sealed housing. The overload protector includes a thermally activated switching device for selectively providing current to the electric motor, a heater element thermally coupled to the switching device, and a control circuit controlling the heater element. The overload protector allows the disconnection of power to the motor due to factors and conditions specified in the remotely located control circuit.

Abstract: A device for controlling the power supply to the electric motor of a starter for a vehicle having a power switch connected in series with the electric motor, units for controlling the power switch, and an auxiliary switch which shorts the electric motor when the power switch is opened, where the auxiliary switch is a static electronic component.

Abstract: The temperature (25, 33, 43) of solid state switching devices in variable speed motor drives (11, 18), such as elevator motor drives, are utilized to reduce the load on the drive, by reducing the switching frequency (50) or the commanded load (110). The choice between the preferred non-switching zero state and an alternative zero state is determined (60) by temperature (28, 34, 56) of the switched transistor's anti-parallel diode. The rate of recognizing reduced temperatures is limited (33, 34) to avoid motor speed and/or load variations. The temperature may either be measured (24, 27) or determined (70) from models utilizing manufacturer product specification and normalized thermal transient response from the transistor/diode package to a heat sink.

Abstract: A circuit and method for permitting uninterrupted operation of a motor, even in the event of an over temperature condition, by dynamically controlling the motor torque based on the temperature of switching devices in the motor controller circuit. The circuit limits the torque current to either a fixed limit value if the temperature of the switching devices (or a current feedback signal for estimating the temperature of the switching devices) is below a predetermined value, or to a variable limit value which is inversely proportional to the temperature signal if the temperature of the switching devices (or the current feedback signal) exceeds the predetermined value. Accordingly, in the event of an over temperature condition, the motor continues to operate, but at a reduced torque, allowing the switching devices to cool.

Abstract: An improvement in a starting system for an electric motor, which drives a hermetic compressor of refrigeration and comprises a main winding (1), and an auxiliary winding (2), which are energized by an electric current source (3), through a hermetic terminal (40) affixed to the outside of the compressor shell, the auxiliary winding (2) having a terminal connected to the electric current source (3) through a starting device (10) mounted inside the compressor shell and in series with a fusible element (20) to be opened when submitted to an electric current, in order to definitively interrupt the energization of the auxiliary winding (2) by means of the starting device (10), said hermetic terminal (40) being designed to receive an external starting device (50), in order to promote the selective connection between said other terminal of the auxiliary winding (2) and the electric current source (3) upon the definitive opening of the circuit defined by the fusible element (20) and the starting device (10).

Abstract: A fuel cell power plant (1) and a rechargeable battery (2) are connected in parallel to an electric motor (3) of a fuel cell powered vehicle, and the output voltage of the fuel cell power plant (1) is regulated by a converter (4). A temperature sensor (5) detects the temperature of the electric motor (3), and a controller (6) controlling the output voltage of the converter (4) to a predetermined high voltage value when the temperature of the electric motor (3) is greater than a predetermined temperature, thereby preventing the excessive rise of the temperature of the electric motor (3).

Abstract: A starting device for electric motors which is designed to be fitted to compressor motors or the like, and includes a PTC resistor in series with a relay inserted between the line and the motor start winding.

Abstract: An electric power steering system is provided which assists a steering operation by applying a driving force generated by an electric motor to a steering mechanism of a motor vehicle. The system includes a sensor (e.g., a torque sensor) for acquiring information necessary for controlling the electric motor, and a board provided adjacent the electric motor and having a sensor signal processing circuit for processing a signal from the sensor. A temperature sensor for acquiring temperature information necessary for controlling the electric motor is mounted on the board.

Abstract: A device for control of an electric motor-driven compressor of an air-conditioning circuit has a control circuit and an inverter for applying a variable frequency to the electric motor for motor speed control. The control circuit includes a potentiometer and a controlled switch and enables a normal-operation mode under the control of the potentiometer as well as a degraded-operation mode in which the speed of the electric motor is a minimum, and a safety mode in which the operation of the electric motor is prevented.

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: A protective device (3) for a hermetic type electromotively driven compressor (1a) includes a protector assembly (30) having a housing (32) with an electric current fuse (34) which detects a predetermined over-current. The housing (32) comprises an electrically insulating skirt member (31) formed so as to block a conductive part on the side facing an external connection terminal. By forming the electrically insulating skirt member (31) of housing (32) for a hermetic type electromotively driven compressor, insulation distance between a conductive part such as the electric current fuse (34) and an external conductive part such as a metal wall part (21) is set to be 9.5 mm or more.

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: 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 starting device (1) has a thermostatic element (14) of a first switch circuit (11), a first resistive heater (13) serially connected to the first switch circuit, a thermostatic element (22) of a second switch circuit (21) and a second resistive heater (23) serially connected to the second switch circuit. The thermostatic element (22) of the second switch circuit is heated by both the first and second resistive heaters and, after actuation, is closer to the first resistive heater (13), thereby bringing the second switch circuit (23) into a de-energized state. When the second switch circuit (21) and the second resistive heater (23) are employed in the motor starting device, it becomes possible to provide a large electric current to the start winding during the start-up phase and to make the electric current that flows to the start winding zero after the start-up phase.

Abstract: The windings of the electromotor at the starting are connected to the main power through starting resistors for a very short period of time, before being directly connected to the main power source.A voltage is initially established at the terminals of a voltage control resistor provided by at least one of the starting resistors, or a fraction thereof, before the running of the motor will occur and the direct connection of the motor windings to the main power is allowed only when the voltage across the voltage control resistor has decreased with respect to the voltage initially established at the starting of the motor. The temperature difference between the voltage control resistor, or a fraction thereof, and the ambient is also sensed and any new start of the motor will be prevented till the temperature of the control resistor is not adequately decreased.

Abstract: A secondary thermal overload device is connected to one winding of a motor having a bi-directional rotatable output shaft and is preset at a lower trip temperature than a trip temperature of a primary thermal overload device connected to the motor to deactivate only the one motor winding effecting closing movement of a garage door at a lower motor operating temperature and before the primary thermal overload device trips while enabling the motor winding associated with an opening movement of the garage door to be activated to open the garage door.

Abstract: A motor speed control circuit includes a temperature sensor providing a first voltage output which is proportional to the temperature and a control voltage generator having an internal voltage reference receiving the first output as an input. The control voltage generator develops a control voltage representative of a desired motor speed profile which varies substantially linearly between a first predetermined temperature and a second predetermined temperature and supplies the control voltage to a motor drive circuit with a motor drive voltage at its output. The control voltage is fed back to the temperature sensor to achieve a controlled, fast rising slope. A second feedback circuit results in a reduced slope of the voltage between the second predetermined temperature and a third predetermined temperature at which an alarm signal is generated. The circuit also is able to detect a stopped motor and provide an alarm.

Abstract: A protecting method and apparatus for a regenerative resistor in which a regenerative resistor is satisfactorily protected from a thermal breakage caused by an over-regeneration by combining a projection of the regenerative resistor by a thermostat and a protection of the regenerative resistor by an analog simulation circuit and by coordinating protective regions of these two protections. The heat-responsive switch (2) stops power supply to a DC link (10) when the temperature of the regenerative resistor is increased to a predetermined value or greater value. The analog simulation circuit (1) is provided with a charge-discharge circuit to be charged and discharged in response to a regenerative pulse signal from a level detector (7), estimates the quantity of heat accumulated in the regenerative resistor (5) by means of the charge-discharge circuit, and stops power supply to the DC link (10) when a predetermined threshold value is exceeded by the estimated value.

Abstract: A motor-driving circuit includes an auxiliary coil which functions at the time of the start-up of the motor and a main coil for its stead state operation. A component of a start-up circuit to be incorporated in such a motor-driving circuit includes a thermistor with positive temperature characteristic and a Triac switch which are to be connected in series with the auxiliary coil, a case which contains both the thermistor and the Triac switch, and a connector member having a planar contact portion, one of its principal surfaces contacting an electrode of the thermistor and the other of the principal surfaces contacting the inner wall surface of the case. The case may further contain therein another thermistor connected to the gate of the Triac switch for controlling the Triac switch.

Abstract: An electrical load, such as a motor, has a first and a second terminal element for supplying electricity to the load. The second terminal element is directly connected to the load whereas the first terminal element together with a further terminal element forms a clamping socket for a switching device. The further terminal element is electrically connected to the load. When the switching device is inserted into the seat, the first terminal element is connected to the load in series with the further terminal element via the switching device.

Abstract: A brushless direct current motor includes a permanent magnet mounted to a rotor and a set of commutated stator windings. The motor further includes a circuit for changeably connecting the set of stator windings to operate in a first electrical configuration or a second electrical configuration and a circuit for commutating the set of stator windings when connected in the first electrical configuration or the second electrical configuration.

Abstract: An electronic protection device for providing thermal protection of a load by cutting off the multiphase supply of power to the load includes a thermal sensor having at least one resistive element thermally coupled to a temperature sensor connected to an electronic processor circuit. This circuit generates a command instruction in response to any overload detected by the temperature sensor. Each resistive element of the thermal sensor is fed with current by a current sensor on a phase wire supplying power to the load.

Abstract: Device for indicating the state of a single-phase asynchronous motor (MO) with a phase-shift capacitor, including an automatic stop switch (FC1, FC2) on each live conductor and a thermal switch (TH) on the return conductor, and the direction of rotation of which can be reversed by means of a changeover switch (CM). The indicator device consists of a current detector (DC), of a voltage detector (DT) and of processing logic (LT) respectively delivering information on the direction of rotation of the motor, the state of the live conductor switches and of the thermal switch.

Abstract: An asynchronous machine uses a short-circuit rotor that is rotatably mounted by means of rolling bearings. Damage to the grease-lubricated bearings of the machine is prevented when the machine is started up in a temperature range below or near the freezing point by providing that: (1) before the machine is started and while the rotor is simultaneously locked, a voltage is applied, as a function of the temperature prevailing at the machine at its stator winding, of such magnitude that a current several times the rated machine current flows; and (2) when a certain temperature is reached at predefined parts of the machine or after a certain voltage application time, the current is switched off and the locking of the rotor is released.

Abstract: A zoning circulator for circulating fluid within a zone in a hydronic heating or cooling system includes a zoning circulator controller including a speed regulating circuit for controlling the speed of a circulator motor. The circulator controller also includes an override circuit for operating the circulator at a high speed, high starting torque for several seconds to overcome frictional resistances between the moving parts of the motor and then tapers down to the speed established by the speed regulating circuit.

Abstract: A starting device for a single phase induction motor can reduce the power consumption and restart in a short time. The starting device for the single phase induction motor having a main winding and a starting winding comprises a starting positive temperature coefficient thermistor connected in series with the starting winding, a bidirectional current control device connected in series with the starting winding and the starting positive temperature coefficient thermistor, and an auxiliary positive characteristic thermistor having a heat capacity smaller than that of the starting positive temperature coefficient thermistor connected in parallel with the starting positive temperature coefficient thermistor, a terminal of the auxiliary positive temperature coefficient thermistor being connected to a gate of the bidirectional current control device.

Abstract: A circuit for starting a single-phase AC induction motor 11 having a main winding 12 and an auxiliary winding 13, which is so constructed that a PTC element 16 and a triac 17 are connected in series with the auxiliary winding 13 and a gate voltage of the triac 17 is reduced to turn a portion between main terminals of the triac 17 off after a predetermined time period has elapsed since the motor 11 was started, and can effectively lower the power consumption without degrading starting characteristics and can shorten return time required until the motor 11 is restarted and lengthen the life of the PTC element 16.

Abstract: A protection circuit for a permanent split capacitor motor includes a positive temperature coefficient (PTC) resistor in series with the auxiliary winding of the motor for protecting the auxiliary winding during normal operation. At a predetermined temperature anomaly due to over-current conditions in the windings, the PTC resistor will sharply increase its resistance to a point wherein no current will pass, effectively open circuiting the auxiliary winding from the power source, thereby protecting the windings from damage. A thermally responsive protector may also be used in conjunction with the PTC resistor for providing further over-current protection to both the main and auxiliary windings.

Abstract: A motor control method for determining the temperature of a motor wherein the operation and nonoperation times of the motor are monitored, an estimated temperature is determined as a function of the monitored times and predetermined temperature rise and temperature fall characteristics of the motor, and the motor is stopped and/or an alaram signal is generated if the estimated temperature exceeds a predetermined temperature.

Abstract: Provided is a spindle drive control apparatus which is provided with a single three-phase spindle motor (60) for rotatingly driving a spindle (50) of a machine tool and a solenoid relay (70) for switching the phase windings (U, V, W) of the motor between a delta (.DELTA.) and star (Y) state and which switches the phase windings to the delta connection when rotating the spindle (50) at high speed for heavy duty cutting work and switches to the star connection for generating the high torque when rotating at a superlow speed (for example, 0.5 rpm) for contouring machining work etc. In this way, it becomes possible to handle the machining work performed in the past with two types of motor by using just a single motor, thus contributing to reduced costs.

Abstract: A microprocessor-based relay system is used in combination with relay contactors and a control circuit therefor to protect an electric motor from overload currents in addition to phase faults, ground faults, load losses, and load jams. The microprocessor is provided with a data base comprising thermal characteristics of the motor during heating and cooling. The heating data comprise current versus time curves stored as a look-up table for which each data point represents a thermal limit, i.e., the maximum time the motor is permitted to operate at a particular current level. The cooling data comprise motor cooling rates. Phase currents are sampled at preselected fixed time intervals during a predetermined period thereof, and an average motor current value is calculated therefrom. A thermal sum, which is initialized at zero upon first starting the motor, is adjusted depending on the average motor current value relative to a predetermined overload current value.

Abstract: A motor winding system having a main winding and a start winding circuit with a start winding and a PTC resistor in series therewith wherein the resistor is electrically removed from the circuit at a predetermined time after motor starting and remains in this state until motor shut off. The start winding circuit also includes a bimetallic switch in series with the resistor and a series circuit of a capacitor and an electromagnet in parallel with the resistor and switch. At motor start up, current from the main power source is applied across the main winding and the start winding circuit heats up the resistor and causes an increase in the resistance thereof. Also, current through the switch and PTC heat causes the bimetallic element to snap or move when it has reached a predetermined temperature to open the start winding circuit.

Abstract: A method of assembling an overload protector for use in a combination starter-protector device adapted to be associated in circuit relation with a dynamoelectic machine. To practice this method, a conductive member is extended through a slot in a sidewall of a casing, and a contact section of the conductive member is located within an open ended recess in the casing defined by the sidewall and a base wall while a terminal section of the conductive member is located on an extension wall extending laterally of the sidewall. The terminal section is secured against displacement to the extension wall. A support for a bimetal switch element is disposed in an assembly position within the open ended recess, and the bimetal switch element is biased into engagement in circuit relation with the contact section.An overload protector, a combination starter-protector device and a method of assembling a starter-protector device are also disclosed.

Abstract: A PTC motor starting device is disclosed including a PTC resistor body having a pair of electrodes disposed on the PTC body and a lead terminal extending outwardly from each of the electrodes. A heat sink material is disposed about the PTC resistor body to absorb the heat generated by the PTC resistor body to reduce the temperature of the PTC resistor body to a temperature below the anomalous or reset temperature. A casing is disposed about the heat sink material.

Abstract: An electric motor armature current control circuit includes an electric motor with an armature in series with a protective device comprising a pair of polymer PTC elements connected in electrical series with the motor armature windings and in electrical parallel and thermal contact with each other. The first polymer PTC element, a temperature compensating element, has a very low cold resistance and a trip temperature higher than the maximum expected ambient temperature to which it is to be exposed in motor operation and generates heat in motor operation to trip to a much higher resistance and become self-regulating at that trip temperature. The second polymer PTC element is maintained at least at the trip temperature of the first through thermal contact and has a lower resistance at that temperature than the cold resistance of the first. Its trip temperature is higher so as to be reached only with excessive armature current.

Abstract: A device providing protection against over-currents in the windings of an electric motor having a rotor (3) and at least two windings (1, 2) comprises at least two parallel thermistors (17, 18) each mounted in series with at least one motor winding (1, 2).

Abstract: A digital controller for synchronous motors prevents excessive heating of squirrel cage windings during motor starting. It reduces motor excitation if the actual accrued excitation time exceeds the maximum allowable excitation time of the controlled motor. It provides for adjustment of allowable time responsive to changes in excitation voltage. The thermal characteristic of the controlled motor is automatically derived from merely a few manually entered set point values.

Abstract: A motor protector of the type having a snap acting thermostatic element is shown particularly adapted for use with compressor motors in which a conventional three pin header is mounted on the compressor casing to allow electrical energization of the motor. An improved heat transfer path is formed between the windings of the motor and the thermostatic element of the protector by suspending the protector from one of the motor pins in optimum heat conductive relation therewith and thermally separated from the compressor casing and any component mounted on the other two pins.

Abstract: A digital controller for synchronous motors prevents excessive heating of squirrel cage windings during motor starting. It reduces motor excitation if the actual accrued excitation time exceeds the maximum allowable excitation time of the controlled motor. It provides for adjustment of allowable time responsive to changes in excitation voltage. The thermal characteristic of the controlled motor is automatically derived from merely a few manually entered set point values.

Abstract: An electrical circuit for connecting an electric motor to an electrical source of supply comprising a double pole single throw switch having four quick-connect terminals thereon. Two of said terminals are connected to the electrical source of supply and the other two of said terminals connected directly to the windings of the electric motor. A centrifugal switch is provided, mounted internally of the housing of the electric motor on an insulated electric circuit board. The supply leads bypass the electric circuit board on which the centrifugal switch is mounted, thus minimizing the number of terminals and electric circuit connections and increasing the reliability and safety of the circuit.

Abstract: A motor starter and protection circuit is disclosed wherein a bimetallic contact support supports moveable contacts which are electrically interconnected with stationary contacts during normal non-overload conditions. Current from the power support passes through the stationary moveable contact sets as well as the bimetallic contact support and through the main coil of the motor. A positive temperature coefficient resistance is mounted on the contact support in electrical interconnection therewith. Current passes through this resistance, a TRIAC, and the motor starting winding. Conduction of the TRIAC is controlled by sensing the current which passes through the main motor coil. Only when the current passing through the main coil is substantially greater than normal load current is the TRIAC gated into conduction. A phase control capacitance is interposed between the coil sensing current through the main coil of the motor and the TRIAC gate.