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 motor-driven power steering system for a vehicle capable of preventing a motor-related element such as a motor itself, power elements for controlling power supply to the motor or the like from being damage due to an abnormal temperature rise or overheating thereof, thereby substantially avoiding or reducing resultant unsureness or instability in the operator's steering feeling upon change in steering mode as well as improving safety in steering operation. The motor is operatively connected with a steering rack and energizable by a power source for power assisting the steering motion caused by the operator through a steering wheel. A temperature sensor detects the temperature of the motor-related element. An electromagnetic switching clutch is interposed between the motor and the steering rack for selectively establishing and interrupting the transmission of power assisting force from the motor to the steering rack in accordance with the travelling speed of the vehicle.

Abstract: A motor-driven power steering system has a steering mechanism for interconnecting a steering wheel and a steerable wheel. An electric motor applies a steering assistive force to the steering mechanism. A plurality of frictional elements are each provided with a lubricating material having a temperature-dependent viscosity. The motor-driven power steering system also includes a steering torque detector for detecting a steering torque applied by the steering wheel through the steering mechanism and for generating a signal indicative of the steering torque a temperature detects for detecting the temperature of at least one of the frictional elements and generates a signal indicative of the temperature. A motor control signal generator generates a motor control signal based on at least the signals from the steering torque detector and the temperature detector. A motor driver controls the electric motor based on the motor control signal.

Abstract: A controlling device for an automobile motor driven antenna including a motor for extending and retracting an antenna by the power from a battery, and a control circuit for controlling the power. The control circuit includes a current detector for detecting the power flowing into and out of the motor and a current breaker which breaks the current when it is over a predesignated level so that a pair of relay contacts in the circuit changes the direction of the current so that the motor may make a forward or reverse rotation for extending or retracting the antenna and automatically make a stop of such rotation.

Abstract: A motor protection relay is taught which determines effective and RMS values of current on a cycle-by-cycle basis by measuring three-phase currents at 10.degree. intervals in a line cycle and then determining the positive and negative sequence components thereof by storing the accumulated information in a memory. In order to increase the dynamic range of the sensing apparatus, only the negative half wave of each current is sensed and the positive half wave is reconstructed by finding the 180.degree. phase shifted equivalent thereof in the negative half wave.

Abstract: A motor protection relay is taught in which the temperature of a rotating rotor is inferred from the current flowing in the lines which supplies the motor and from resistance temperature detection devices in the stator of the motor. By utilizing a periodic predictable established interrupt routine within the software which controls the microprocessor which in turn controls the monitoring device the time based model for inferring rotor temperature can be freed of a requirement to use a fixed sampling time rather the time for calculations can be variable. The total number of counts that particular interrupt routine has taken place will be factored into the calculations to make the calculations accurate. The thermal model is further improved by expressing it in terms of current squared times time so that the component portions of the equation which represents the thermal model can use accumulator inputs into which values of line current squared have been previously placed.

Abstract: A power unit for a battery-driven toy containing a battery power source for energizing a driving means through a power switch and a controlling circuit is disclosed, in which the controlling circuit comprises a circuit element for controlling said driving means and its movable operative contact, said circuit element being provided with a thermo-switch and a reset circuit for setting said movable operative contact into an OFF position through said thermo-switch.

Abstract: A device for mounting a thermal overload protector to the motor of a hermetic refrigeration compressor. The overload protector is temperature responsive and is operative to protectively interrupt the current to the motor when the stator windings, rotor, or other heat source in the compressor overheats due to a compressor overload. The protector's mounting device is a plastic receptacle having a shield connected by an integral hinge. The hinge not only facilitates manufacturing the receptacle as a unitary part by an injection molding process, but also enables the shield to be opened for inserting the overload protector into the receptacle. The overload protector is held firmly in place by a U-shaped bracket integrally disposed inside the receptacle. A U-shaped groove runs along the inner edge of the bracket and is designed to slidingly engage protectors of various shapes. The receptacle includes an opening on one side of the protector opposite the heat retaining shield.

Abstract: The fan speed controller disclosed herein is particularly useful in the cooling of electronic equipment and provides a feedback control characteristic from an exhaust air temperature sensor such that the change in outlet temperature over the range of air flow rates is substantially equal to the change in temperature rise of typical heat generating devices in electronic equipment over that same range. Accordingly, device temperature is maintained substantially constant over a range of varying input air temperatures. Preferably, the controlled fan includes a d.c. motor which is energized in a pulsed d.c. mode to prevent stalling or instability at low flow rates.

Abstract: A thermistor circuit for sensing the temperature of an intermittent duty wound field motor is connected between the field and armature windings of the motor. When the field and armature winding currents are substantially zero (off duty), the resistance of the thermistor circuit is sampled by the motor controller, using the armature and field winding conductors.

Abstract: A motor protection relay is provided which is programmable to limit the number of starts which are allowed in a given interval of time. In accordance with the algorithm associated with the relay microprocessor for controlling the starts per time, old starts which no longer fall within the same time constraint set by the operator or user are discarded and the time constraint is updated according to the next oldest start time.

Abstract: An obstruction sensing and control arrangement for door or gate opening-closing mechanisms. The arrangement compares the operating rate of change of a predetermined characteristic with a preset rate of change and stops or reverses the motor in the opening/closing mechanism. The characteristic preferred is motor body temperature which is monitored indirectly. The control arrangement also includes a back up static control threshold to sense a second static operating characteristic of the motor and a second comparator means set at a preset threshold level to stop or reverse the motor. A common motor sensor is used for both the dynamic and static control thresholds. The invention also includes means to sense operating temperature and to alter the preset static threshold level automatically in response to temperature changes.

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: The present device includes a resistor network wherein the values of the resistors are chosen such that the heat generated by current passing through the resistors will be substantially equal to heat generated at a semiconductor junction which is to be cooled. The present device further includes a heat sink which is substantially identical to the heat sink employed to withdraw heat from the semiconductor junction to be cooled. Accordingly, the present device provides heat which is identical to the heat generated at the semiconductor junction and which heat remains ambient to the semiconductor junction to be cooled. The present device further includes a sensor which converts temperature to an electrical signal and which is located substantially in the center of the resistor network and at a distance from the heat sink that approximates the position of the semiconductor junction from its heat sink.

Abstract: The fan speed controller disclosed herein mounts directly on a fan whose speed is to be controlled and provides electronic speed control circuitry mounted in a disk-like enclosure aligned with the fan hub. The enclosure is compartmented and apertured to provide a representative air flow past a temperature sensitive element employed by the circuitry. Fan speed is controlled as a function of air temperature above a sharply defined minimum to provide effective cooling with minimal noise generation.

Abstract: Gyroscopes, particularly those with permanent magnet torquers, may be temperature sensitive. A temperature signal may be derived and used to correct the temperature dependent parameters such as gyro scale factor. Herein, instead of or in addition to such correction, it is proposed to regulate the gyro temperature by varying the torquer signals and hence controlling the power dissipated in the torquer coils. The torquer signals may comprise positive- and negative-going pulses of fixed amplitude and having respective durations appropriate to produce the required torquing effect. Then, the dissipated power can be controlled by varying the durations of the inter-pulse dead-zones.

Abstract: An apparatus for controlling an airflow to a boiler or the like and maintaining a desired quantity thereof. The apparatus comprises a controller for generating a control signal of a level corresponding to a required airflow, a variable-frequency power supply for producing an output of a frequency corresponding to the control signal level so as to drive a ventilation-actuating motor, and means for detecting any deviation of the control signal level from a predetermined range and retaining the frequency of the motor-driving output at a proper value, whereby the airflow is maintained at or above a preset value.

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 process for controlling the speed of an electric motor. A reference value of motor temperature is provided and directed to a summing junction. The actual temperature of the motor is sensed and also directed to the summing junction. The two values are summed and employed as a reference of motor current. This reference is directed to a second summing junction while the value of actual motor current is sensed. The actual value is also directed to the second junction. These last two values are summed at the second junction to provide a reference for adjusting motor speed.

Abstract: An improved electric power steering system is disclosed. The system includes an electric motor as a driving device. Input system torque, motor current flow and motor temperature are detected and used to control the motor to prevent premature failure of the system due to elevated temperatures in the vehicle engine compartment.

Abstract: Agricultural fan control system for controlling operation of fan in an agricultural installation including a thermostat temperature control, a manual constant speed adjustment temperature control, and an automatic variable fan speed with a minimum temperature setting. The control system is fully enclosed in a dustproof, waterproof box with a spring-loaded cover for use in a barn. The sensor unit can be remote from the control unit, and accounts for a seven-degree fahrenheit temperature rise on modulating setting from minimum to maximum c.f.m. Voltage curve of the electrical system is inverted and slower so that there is a slower fan speed increase on the first five degrees than on the last two degrees temperature-wise. The system includes a minimum setting allowing for a constant minimum air movement while including a manual setting for maintaining constant maximum air movement. The c.f.m. to heat requirements is adjusted accordingly between 45.degree.-110.degree. F.

Abstract: A microprocessor controlled motor starter is utilized in which the short term temperature differential between the rotor bars and the rotor end bells is accounted for by the microprocessor-based system as a function of operator programmed stall time and locked rotor current for the particular rotor in question. The latter information is supplied to the operator by the manufacturer of the motor. The foregoing takes into account a slight deviation between the shutdown temperature, which should be predicted as a function of the manufacturer's data, and the actual shutdown temperature as expressed by an exponential. In the event that the short term temperature differential is exceeded, the microprocessor will enter a TRIP routine causing the motor controller to shut the motor down, thus preventing serious damage to the motor.

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: A motor starter, which may be microprocessor-controlled, is taught wherein a signal conditioning means is provided for receiving from the motor windings parallel inputs and motor bearings which are related to the motor winding and bearing temperatures and for operating on these parallel input signals in such a manner as to provide a single serial output signal for use by a control means to cause the motor control starting sequence or the normal motor run condition to be interrupted, for example, if any one of the temperatures is above a predetermined level.

Abstract: A network controlled inlet is provided for current sensing in a comparator to control the current in direct current motors. An electrical signal generated from a physical parameter is conducted to the first input of the comparator and a signal characterizing the speed of the motor is conducted to the second inlet of the comparator.

Abstract: A circuit, safe against an overload, for incrementally varying the power to an electric blower motor used for heating, ventilating and conditioning vehicles, having a PTC resistor in series with other series resistors in the circuit.

Abstract: In an apparatus for controlling the speed of the blower motor in response to the difference between the temperature setting and the temperature inside the vehicle, the maximum speed of the blower motor is limited in accordance with the temperature of engine coolant. Consequently, the quantity of air issuing from the blower is always such that it does not make the passengers feel uncomfortable.

Abstract: Disclosed herein is an outboard motor having a control circuit for a permanent magnet, direct current motor, which circuit comprises a source of direct current, a permanent magnet motor including an armature winding having opposed terminals, control means including a first resistor connected between one of the armature winding terminals and the direct current source, a second resistor connected to the one armature winding terminal, a shunt lead connected to the one armature winding terminal, and a speed control switch connected to the direct current source and selectively operable between a first position connecting the direct current source to the shunt lead in parallel with the first resistor and disconnected from the second resistor, a second position connecting the direct current source to the second resistor in parallel with the first resistor and disconnected from the shunt lead, and a third position disconnected from both of the shunt lead and the second resistor, whereby current flow from the current

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 device responsive to an unusual temperature change in a refrigerant compressor using an electromagnetic clutch including a magnet coil as an actuating element of the clutch, comprising an overcurrent-responsive element such as a fuse connected in parallel with the magnet coil, a temperature-responsive switch operative to be open when the temperature in the compressor rises beyond a predetermined value, and a switching element such as a transistor which is non-conductive when the temperature-responsive switch is closed and which is made conductive to cause the fuse to melt when the temperature-responsive switch is made to open.

Abstract: A tapping machine having a spindle which is moved reciprocally, i.e., in advancing and retracting direction while being rotated forwardly and backwardly for forming a female screw in a work with a screw tap attached at one end thereof. The machine is provided with driving means including a reversible electric motor, position sensing means for generating a sensing signal when the spindle is moved in advancing direction from a start position so far as a predetermined position, and temperature sensing means for generating a sensing signal when the temperature of the electric motor has risen exceeding a predetermined value. The machine normally repeats a working cycle wherein the spindle is moved in advancing direction from the start position while being rotated in forward direction until it is retracted to the start position soon after a sensing signal from the position sensing means has been generated.

Abstract: A refrigerating device having an inverter circuit for generating alternating voltage, a vibrating compressor to which the alternating voltage from the inverter circuit is supplied, a condenser to which the refrigerant compressed by the compressor is supplied, a capillary tube provided on the downstream side of the condenser and an evaporator provided on the downstream side of the capillary tube, wherein a phase control circuit for controlling the phase of the alternating voltage supplied to the compressor in accordance with ambient temperature of the refrigerating device and/or the evaporator temperature is provided to cause the piston stroke of the vibrating compressor to be reduced in accordance with decreases in ambient temperature of the refrigerating device and/or the evaporator temperature so as to prevent unwanted damage to the compressor.

Abstract: An electric motor of predetermined voltage rating is connected to an electric current supply source higher in voltage than the rated motor voltage in series with a voltage dropping resistor controlled by a thermal relay responsive to motor temperature. The series circuit is regulated by the relay to include or exclude the resistor thereby to maintain motor temperature at normal rated value.

Abstract: A hoisting apparatus and a control circuit therefor comprising a reversible electric motor drivingly connected to a hoisting drum for hauling an object up and down. The control circuit includes first and second photosensitive elements each responsive to a light beam for initiating rotation of the electric motor in either direction and means for terminating rotation of the electric motor.

Abstract: A stationary device for sensing the rotational speed of electric motors, comprising an impedance bridge circuit, the motor being inserted into one branch of the bridge in series with a resistive element, and a voltage proportional to the rotational speed being derived across a diagonal of the bridge, the resistive element being a winding wound directly on to the motor, in order to make it isothermic, and insensitive to the magnetic field of said motor by a form of winding of the "two wires in hand" type.

Abstract: A three phase motor is constructed with each of the three phase windings thereof split in half so that the motor may be selectively connected for energization from either a relatively high or relatively low source. Motor protectors are provided in the form of a three pole automatic resetting overload relay means and two thermostatic switches. The heaters for the individual poles of the overload relay means are connected in series with a half section of the individual phase windings and do not have to be changed when either high or low voltage energization is selected for the motor. The thermostatic switches are embedded in two of the other three winding sections but electrically insulated from the motor winding. The control contact means of the overload relay means and the thermostatic switches are connected in series with the energizing coil of the electromagnet for the contact through which the motor is connected to its energizing source.

Abstract: A control circuit is provided for a d.c. motor for sensing the temperature of the field winding and automatically reducing the temperature of the field winding when the temperature exceeds a preselected value.

Abstract: A refrigerating system having a compressor; an inverter connected to the compressor for supplying electric energy to the compressor; and an input voltage control circuit provided on the input side of the inverter, wherein the input voltage control circuit generates output voltage signals which change at a predetermined level, including zero level, within a certain temperature range in response to the ambient temperature of the refrigerating system and in accordance with the temperature condition, the voltage thus produced being fed to the compressor via the inverter. The refrigerating system of this invention is, therefore, protected from failure or damage even when placed in an extreme temperature environment, and resumes automatically the supply of power to the compressor when the ambient temperature of the system is restored to the normal temperature.

Abstract: Apparatus for preventing damage to resistor grids in the propulsion controller circuit of a direct current motor, particularly of the type used in driving railway vehicles, in which a line breaker relay is de-energized whenever the propulsion controller fails to progress from the switch position to the full series position within 15-25 seconds. The line breaker relay remains de-energized for the duration of the power cycle of the propulsion controller and becomes operational automatically after the master control handle is returned to the off position.

Abstract: Disclosed is an apparatus for controlling an electric motor for driving a cooling fan of an internal combustion engine. The apparatus comprises an engine operation detecting means, a timer, an engine temperature detecting means, a logical product generating means, and a motor controlling means. The electric motor is driven only when all of the following three conditions are satisfied: the engine is not operating; a predetermined timing period initiated when the engine stops operating has not expired; and a temperature in the engine room is higher than a predetermined value.

Abstract: Disclosed herein is a control for a direct current motor including a field weakening solenoid switch including a solenoid coil, which control includes a switch connected in series with a coil for connecting and disconnecting the coil to a source of direct current, and a device responsive to motor speed for operating the switch.Also disclosed herein is an overspeed control for a direct current motor including a solenoid switch which controls energization of the direct current motor, which is biased open, and which includes a solenoid coil operable in response to energization thereof to close the switch, which overspeed control comprises a switch connected in series with the coil for selectively connecting the coil to a source of direct current, and a device responsive to motor speed for operating the switch.

Abstract: A motor control circuit for preventing automatic restarting of an electric motor following an interruption of electric current flow therethrough. An electric motor incorporates winding means and a series automatic reset thermal overload protector. Current flow to the motor is normally controlled by current supply switch means in series with the motor across electric power input terminals. A first relay device is switched by external actuation of a normally open start switch to switch the current supply switch means to its conductive state for starting the motor. A second relay device connected across a pair of motor terminals is energizable in response to current flow through the motor. A restart prevention switch connects in series with the current supply switch and motor across the electric power terminals.

Abstract: A system is provided for preventing overtemperature of the rotor bars of large squirrel-cage induction motors. A transmitter is mounted on the rotor and supplied with power from the rotor winding itself by a special current transformer. The transmitter is controlled by a temperature sensing element which causes it to transmit a signal in response to excessive temperature, and a slip frequency signal is also transmitted as a reliability check. A stationary receiver picks up the signal from the transmitter and includes circuitry for deenergizing the motor in response to the excessive temperature signal and for preventing energization of the motor if the slip frequency signal is not received.

Abstract: A method of protecting auxiliary winding means and main winding means in a winding circuit of a dynamoelectric machine in the event of a current overload. In this method, means is actuated in response to a preselected thermal condition accompanying the current overload for interrupting the winding circuit. Heat is transmitted from means for controlling starting of the dynamoelectric machine to the interrupting means for generally maintaining the winding circuit effectively interrupted for at least a predetermined period, and the starting controlling means is operable generally in response to current flow therethrough to increase its resistance generally as a function of its temperature for impeding the current flow therethrough to the auxiliary winding means at a preselected speed of the dynamoelectric machine.A combination starter-protector device, a method of operating a dynamoelectric machine, and a circuit are also disclosed.

Abstract: An earth excavator including apparatus for stabilizing performance by compensating for changes in temperature. The apparatus includes a temperature compensating voltage regulator for regulating and controlling the output voltage of an exciting generator as a function of sensed temperature. The exciting generator supplies field excitation voltage and current to electric motors in the earth excavator. In order to maintain substantially constant current through the motor field windings with variations in temperature of the windings, and therefore to maintain the performance of the motors and thus of the excavator substantially constant with variations in temperature, the exciting generator output voltage is regulated in a manner such that the regulated voltage supplied by the exciting generator is a direct function of the temperature of the motor field windings. The output voltage of the exciting generator is controlled by controlling the average current through the exciting generator field winding.

Abstract: A motor is electrically coupled to a power source through a motor starter. The motor starter is selectively operated by a relay to connect and disconnect the power source to the motor. A counter is set whenever a select motor temperature condition exceeds a predetermined level to provide an indication of the number of motor starts. The relay is operated to cause the motor starter to disconnect the power source from the motor whenever the motor fails to run continuously during a given time period following a predetermined number of starts.

Abstract: A motor control circuit for controlling the operation of a motor having main running-speed windings and also start-up windings includes a fixed time delay circuit to energize the main windings after a time delay following energization of the startup windings. In addition a lock-out circuit is provided to prevent re-start of the circuit following a particular fault condition.

Abstract: A combination starter-protector device for a winding circuit of a dynamoelectric machine. The device has a housing with at least one terminal therein adapted for connection with a power source, and means is provided in the housing for controlling starting of the dynamoelectric machine. Means is mounted to the housing for electrical contact and positioning engagement with the starting controlling means and adapted for connection in circuit relation with the winding circuit. Another circuit is provided between the engagement means and the at least one terminal for supplying power to the winding circuit when the engagement means is connected in circuit relation therewith, and the other circuit includes means in the housing and operable generally in response to a certain thermal condition occasioned upon winding circuit overload for interrupting the other circuit.Other combination starter-protector devices are also disclosed.

Abstract: A motor protection circuit has a current sensing means connected in series with a contactor winding energization circuit for sensing current flow to initiate operation of a delay after break circuit or to maintain an oil pressure protection circuit unoperated.