Abstract: This disclosure provides a motor control system and method that is preferably applied to cargo power drive units. Power is supplied to a motor having one or more windings and a thermocouple that is embedded in the motor windings. The thermocouple provides an electronic signal from which both motor temperature and rate of temperature change are derived. A motor control circuit uses these values to determine if a jam condition has occurred (as represented by improper temperature rise) or whether critical overheating is occurring. If so, the motor control circuit causes a power switch to disconnect power from one or more PDUs in the subject bank of PDUs. Power is temporarily disabled, until a cargo operator releases a joy stick control to a neutral position and then attempts to use it again.

Abstract: A control method for an alternating current motor, wherein after a torque command Tcmd1 is obtained, if the motor is accelerating, and the obtained torque command Tcmd1 is found to not exceed a predetermined limit value K.sub.0, the torque command Tcmd1 is directly outputted as a torque command (a current command) Tcmd.sub.2 to each phase current loop circuit which controls the current flowing through each phase winding of the motor. If the torque command Tcmd1 exceeds the limit value K.sub.0, an amplitude I.sub.0 of the actual current is obtained. A limit value L is obtained based on a magnitude R(T) of the torque command Tcmd2 obtained one period before and the limit value K.sub.0. The torque command Tcmd1 is clamped by the limit value L to provide the torque command Tcmd2 to be supplied to the current loop. When the motor is decelerating, the control method compares the torque command Tcmd1 with the predetermined limit value K.sub.

Abstract: A motor controller for a vehicle including an electric motor that drives the vehicle, a plurality of sensors and a vehicle power controller. The vehicle power controller receives signals from an accelerator sensor and a brake sensor, converts the signals for the accelerator sensor and the brake sensor into a torque value. The motor controller comprises three components. A first component receives the torque value from the vehicle power controller. A second component converts the torque value into a torque output; and a third component controls the motor in accordance with the torque output.

Abstract: A control circuit for controlling a linearly variable speed cooling D.C. fan includes a stator including at least two pairs of main poles, two pairs of auxiliary poles and a Hall effect element provided at either of auxiliary poles. The control circuit also includes a rotor which as a casing, at least two pairs of N and S poles and a plurality of blades. Further, the control circuit includes a driving IC including an amplifier and two switching transistors, a temperature sensor detachable to a connector means, for determining a revolution speed of the D.C. fan that matches to the detected temperature, and a breakdown protection unit provided between said driving IC and said temperature sensor.

Abstract: A refrigeration control apparatus especially adapted for use in conjunction with cryogenic coolers includes a brushless variable speed drive motor for powering a mechanical cooler-compressor and electronic control circuitry coupled to the motor allowing motor speed and hence cooling rate to be responsive to changes in the temperature of the volume sought to be cooled. A signal corresponding to sensed temperature is compared to a reference signal derived from motor speed. The difference therebetween used to vary the duty cycle of a high frequency pulse train. The pulse train is used to modulate the drive current applied to the motor through pulse position switching circuitry to vary the speed of the drive motor. High and low motor speed limits are provided along with sensor failure protection circuitry to insure continuous motor operation between chosen limits.

Abstract: Method and apparatus for monitoring the temperature of a resistor in a resistive current controller. The heating and cooling rates for the resistor are determined and a predicted temperature of the resistor is automatically calculated at the beginning each time interval of consecutive time intervals by subtracting from the previous temperature prediction for the resistor the product of the cooling rate of the resistor and the time interval and adding the product of the heating rate of the resistor and the time interval. An actuating signal is produced when the predicted temperature of the resistor for a given time interval corresponds to a threshold temperature.

Abstract: There is disclosed a motor drive circuit, into which an output circuit for supplying a drive output to a motor is incorporated, having a temperature compensating circuit or an output current regulating circuit added to a transistor, interposed between a servo IC for generating a servo signal and the output circuit, for supplying the output circuit with a drive current corresponding to the control output. A dependency on the temperature is obviated by arbitrarily setting an operating point of the output current and compensating temperature characteristics, and the motor is thereby protected from an excessive current.

Abstract: A temperature controlling system for investigating thermal transformation having a program-controller operated furnace the temperature of which is changed with a predetermined speed, and into which a sample and a reference substance containing elements with identical thermal parameters are placed. The sample and the reference substance containing elements are coupled with temperature sensing elements detecting their temperature and both elements are connected to a temperature comparing unit forming the difference of the two temperatures. The output of the temperature comparing unit is coupled through a differentiating network, limit switches and an actuating unit with a quasi-static temperature input of the program controller.

Abstract: A method for the low-loss regulation of a collectorless direct current motor and a semiconductor circuit has, during the commutation phase given by a position sensor and with reduced motor output and number of revolutions, transistors or one end transistor which initially operates temporarily as a switch and thereafter operates temporarily as an analog amplifier element. During the analog period, a current is available which changes slowly according to a ramp function.

Abstract: A closed-loop, temperature-controlled cooling system includes a Stirling cycle refrigerator driven by a dc motor, wherein the motor excitation derives from pulse width modulation. Temperature control of the cooling system is provided by a temperature-sensitive bridge circuit which responds to variations in temperature by generating an error voltage which effects a change in the modulator duty cycle. The amount of cooling is directly related to the average voltage applied to the motor, which is a function of the modulator duty cycle and the amplitude of the supply voltage. A compensation circuit is disclosed which responds to variations in the voltage amplitude of an unregulated supply by coupling an error signal to the bridge circuit to thereby affect the modulator duty cycle.

Abstract: A reversible electric motor is operatively arranged to drive an air circulating fan. Circuitry is provided to reverse the direction of rotation of electric motor periodically to provide alternating direction of air movement. Timing and reversal is provided by either a timing clock, a microprocessor, a thermal relay or a rotating disc which carries a pair of touch stops therein.

Abstract: A thermal model of an electric apparatus such as a transformer or motor, from which signals can be obtained representing temperatures of the conductors and of the adjacent core material, includes storing first and second values, respectively, representing conductor temperature and core material temperature. The magnitude of the current(s) in the apparatus is sensed and a digital signal representative thereof is added to the first value to represent heat generated in the conductors. Values are determined for both heat transferred from the conductors and heat transferred into the apparatus core based on the difference in the first and second values. The value representing heat transferred from the conductor is subtracted from the first value to give a new first value and the value representing heat transferred to the core is added to the second value.

Abstract: A method and device for controlling a power steering apparatus for performing power steering by controlling a rotational speed of a motor-driven oil pump, wherein an alarm signal is generated when the power steering apparatus is overloaded, and a current is not supplied to a motor for a predetermined period of time when the power steering apparatus is overloaded.

Abstract: A refrigeration compressor is disclosed which includes a compressor means, a two phase motor drivingly connected thereto and an associated power supply operative to convert single phase 60 hertz alternating current to two phase controlled frequency alternating current so as to enable the compressor to be operated from conventional single phase power and at any point within a range of speeds commensurate with the loading thereon. The power supply also includes improved filtering means for each of the output phases of the power supply. A line break motor protector is also provided which is particularly well suited for use with two phase motors. Additionally, in order to increase reliability, circuitry is also provided for directly connecting the two phase motor to the single phase power supply in such a manner so as to enable the two phase motor to be operated directly from the single phase supply in the event of failure of the two phase power supply.

Abstract: An apparatus for predicting the remaining useful life of a motor uses the temperature and past history of the motor to determine the amount of insulation degradation for its prediction. The remaining useful life projection is provided at a display and may be used to trip the circuit breakers supplying power to the motor when projected life is shorter than the expected life or may be used to issue a warning that the rate of motor degradation exceeds the rate necessary to achieve the expected life for the motor.Motor protection is provided by tripping the circuit breakers supplying power to the motor before the actual temperature of the motor windings exceeds the temperature at which catastrophic and irreversible insulation failure would occur while not tripping the breakers for momentary transients.

Abstract: A motor drive for a hot melt adhesive pump is maintained in an inoperative condition until the adhesive has heated sufficiently to permit free operation of the motor. The adhesive is received in a container supported upon a heater which is activated to heat the container and the adhesive therein. The output of a proportional control for the heater, which is responsive to the container temperature, is monitored. The output of the proportional control, when the container temperature is near a set point temperature indicative of a desired heated condition for the adhesive, is an intermittent signal. In one form of the invention, the intermittent signal is electrically integrated to produce an interlock release pulse permitting operation of the motor. In a second form of the invention, a thermal relay is coupled to a source of electrical power through a switching circuit, which permits power to be coupled to the thermal relay during the intermittent off times of the heater.

Abstract: To provide for effective cooling of an automotive-type alternator and/or other equipment within an automobile, for example the radiator or other heat exchanger, even under external high-temperature conditions and low engine speed (n.sub.E), for example under idling conditions, the alternator phase windings (6, 7, 8) are connected to respective phase windings (16, 17, 18) of a three-phase squirrel-cage motor which is connected to a blower (2), preferably a radial-type fan, directing forced air circulation towards the alternator and/or the vehicle radiator, the alternator then being placed within the airstream of the radiator as well. A temperature and/or speed-responsive switch can be interposed between the alternator and the motor to energize the motor only if the temperature of the alternator and/or the engine, or other component, rises above a predetermined level, or if the alternator speed drops below a predetermined level.

Abstract: Disclosed is an apparatus for controlling a motor unit including a variable-speed reversible main motor for driving a load and a subsidiary motor for driving a fan. The control apparatus comprises a temperature sensor circuit sensing the temperature of the main motor and generating a first output signal when the temperature of the main motor exceeds a first predetermined level, a second output signal when the main motor temperature exceeds a second predetermined level higher than the first predetermined level and a third output signal when the main motor temperature drops to a level lower than the first predetermined level, and a control circuit connected to the temperature sensor circuit for energizing the subsidiary motor in response to the first output signal, deenergizing the main motor in response to the second output signal and deenergizing the subsidiary motor in response to the third output signal.

Abstract: A digital control system for electric motors in power tools of the portable or stationary type includes a microcomputer controlled speed regulator connected to the electric motor for maintaining a preselected speed of the motor substantially constant between no load and full load operation of the motor. The preselected speed is inputted to the microcomputer by means of a rotary switch or similar input switching arrangement. When the tool is just starting or the operator changes the speed switch, the microcomputer controls the speed of the motor to slowly approach the desired speed. The microcomputer is programmed to detect an overload condition and activate an alarm, and an impending kickback condition and stop the electric motor.

Abstract: A refrigerant compressor of the type driven by a single phase motor capable of operating at a low speed and a high speed. The motor, including four separate windings, a first set of high-speed two-pole auxiliary and main windings, and a second set of low-speed four-pole auxiliary and main windings all wound on the same stator core. Each set of windings is provided with independent line break protectors that enable each set of windings and protector to be optimized without affecting the other. A mandatory low-speed start system is incorporated that insures initial low-speed start even when conditions require high speed operation. Speed switching from one speed to the other is accomplished in the present system while the motor is running without causing interruption of compressor operation.

Abstract: A vacuum hose assembly, method of making same, and vacuum cleaner employing same are provided wherein the hose assembly comprises a thermally actuated switch which breaks the electrical circuit through cooperating electrical leads of an electrical system thereof once a predetermined temperature level is reached by the switch to prevent the possibility of fire and electrical shock in the event of fire-exposed leads.

Abstract: To protect a motor from overheating, its temperature is simulated at a point remote from the motor and the motor voltage is controlled to prevent overheating. The simulator comprises a cube of copper carrying a pair of heating elements: one being heated by a current proportional to motor current and the other heated by a current proportional to motor power. A temperature detector on the cube detects temperature corresponding to critical motor temperatures and is used to control motor energization.

Abstract: Constant condenser pressure is maintained in a refrigeration system by modulating the speed of at least one fan motor of an air-cooled condenser coil in response to the temperature of the refrigerant in the condenser coil, the speed varying directly with temperature. Motor speed variations are achieved by controlling the conduction time of a triac which couples the fan motor to a source of alternating voltage. The triac is triggered into conduction at a phase angle, following the beginning of each half cycle of the alternating voltage, determined by the charging rate of a timing capacitor which charges through a photosensitive transistor optically coupled to an LED. Variation of the refrigerant temperature in the condenser coil changes the light emission of the LED and this in turn varies the charging current translated to the capacitor. The greater the temperature, the greater the charging current and the faster the triac conducts following the start of each half cycle.

Abstract: A protection system for an electric motor including a safety switch to deenergize the motor upon the occurrence of a potentially deleterious operating condition. The protection system includes a current sensitive device in series with the motor. The device is deenergized when the motor is deenergized due to the occurrence of the deleterious operating condition. The protection system further includes a holding device having a normally closed switch electrically connected thereto. The holding device is energized and its switch is opened when the current sensitive device is energized. The holding device remains energized, even though the current device is deenergized, to prevent the motor from being reenergized. The holding device is deenergized to permit reenergization of the motor by the manual opening of a switch connected in series therewith.

Abstract: A method for regulating the material feed to a processing machine, particularly a comminuting machine wherein the actual value of the temperature of the motor winding or windings is measured with the aid of a temperature sensor and is compared in a control regulator with a predetermined theoretical or reference temperature which lies somewhat below the maximum permissible winding temperature of the motor. The difference between the actual value and the reference value effects production of a signal which is applied to an auxiliary regulator for comparison with the actual motor current to derive a reference speed signal for comparison with the actual speed of the aggregate feed conveyor for adjusting aggregate feed.

Abstract: A peak load control and power-distributing system for residential or small commercial/industrial use in which some loads are uncontrolled and others are controlled. Current transformers in the main feeder for all loads supply current to a thermal switch to detect when the power demand exceeds a predetermined value. The thermal switch starts a small synchronous motor having gears driving a shaft with cams operating microswitches for the controlled loads. One cam switch enables the motor to operate through a preprogrammed cycle, and to turn off at the end of a cycle whenever the thermal switch indicates the power demand has dropped below the predetermined value.

Abstract: A method for the low-loss regulation of a collectorless direct current motor and a semiconductor circuit has, during the commutation phase given by a position sensor and with reduced motor output and number of revolutions, transistors or one end transistor which initially operates temporarily as a switch and thereafter operates temporarily as an analog amplifier element. During the analog period, a current is available which changes slowly according to a ramp function.