Abstract: A method and a circuit arrangement for stopping the test run of a rotor being balanced, in particular a rotor for a motor vehicle wheel. Upon the application of an armature disk of an electromagnetic brake to a friction lining, the electromagnet coil of the brake is supplied with a reduced supply current, so that a reduced braking moment by comparison with the rated braking moment is attained.

Abstract: A motorized window blind actuator including input means for receiving regulated voltage and first variable reference voltage signal. A motor having an output shaft which connects to the window blinds to open and close the window blinds is controlled by a controller/driver component. A transducer is operatively associated with the output shaft of the motor to assist in producing a second voltage reference signal which is related to the actual position of the motor output shaft, and in turn related to the actual position of the slats of the window blind. The first voltage reference signal is related to the desired setting and position of the window blind. First and second voltage reference signals are continually compared. If they are sufficiently different, the motor is directed by the controller/driver to adjust the window blinds until signals are sufficiently the same, or, until the output shaft of the motor hits physical limits which cause an over current situation resulting in stoppage of the motor.

Abstract: A method of controlling current in an AC motor to inhibit small torques on an unloaded motor output shaft and to improve buildup of steady-state operating flux in a rotor includes supplying current to the stator windings through a plurality of semiconductor switches, operating the semiconductor switches to supply a plurality of gradually increasing currents to the stator windings over a time interval corresponding to approximately one rotor time constant to bring flux in the rotor up to approximately 10% of a steady-state operating flux in the rotor, operating the semiconductor switches to supply a current that is the maximum current rated for pulsed operation of the semiconductor switches for a time interval over which a product of current and time is sufficient to produce steady-state operating flux in the rotor, and then reducing the stator current to a level for maintaining steady-state operating flux in the rotor. A microelectronic apparatus for carrying out the method is also disclosed.

Abstract: A control device monitors the elapsed off time of an oil filled deep sea electric motor 4, and compares this with a calculated time for the oil temperature to drop to a predetermined value at a sensed water depth. When the two times are equal a low, heating current is supplied to the primary winding 11 to prevent the oil from becoming more viscous. The heating current is insufficient to rotate the motor armature, and its intensity is increased with depth corresponding to the decrease of the water temperature with depth.

Abstract: A device for preventing a motor from being locked comprises a position indicator for indicating a position to be moved in response to rotation of the motor, a position detector for detecting the position being moved in response to rotation of the motor, a servo control unit for supplying a current to the motor so that an output signal from the position detector will be equalized with an indication by the position indicator, a stop detector for detecting stoppage of the motor in response to a differential of the output signal from the position detector, and a cutoff control unit for cutting off the current supplied from the servo control unit to the motor in response to an output signal from the stop detector.

Abstract: A slow motion actuating device has a housing with a first opening therein through which an output pin extends. The output pin is connected to a swing arm which is pivotally mounted in the housing and driven by a set of reduction gears. Stops are provided in the housing for limiting movement of the swing arm. An electric motor is mounted in driving relation with the gear set. The motor has a stall current which is low enough to allow the motor to be continuously stalled without damaging it. A printed circuit board is mounted in the housing with a tail portion extending through a second opening in the housing. The circuit board provides electrical connections to the motor and auxiliary contacts which can be opened and closed by a wiper mounted on the swing arm.

Abstract: A microtome has a specimen holder which executes a vertical up and down movement relative to a cutting knife and which has a guide mechanism in which a sleeve is arranged so as to be horizontally displaceable. The sleeve is provided at its front end with a specimen clamping mechanism and in its interior with a micrometer nut which is secured against axial displacement and through which extends a micrometer spindle mounted on the guide mechanism. The micrometer nut has on its outer face a toothed ring which is connected operatively to a pinion connected to an electric motor. When the electric motor is activated the sleeve is displaced in the guide mechanism. The micrometer spindle extends, on the side opposite the specimen clamping mechanism, through the guide mechanism as a stub end on which is located a mechanical cutting-thickness advance mechanism.

Abstract: A control system for a compressor motor used with an air conditioning unit is disclosed. A current for generating a non-rotating magnetic field is supplied to the compressor motor to preheat a compressor. A current for generating a rotating magnetic field is also supplied to the compressor motor together with the current for generating a non-rotating magnetic field to heat the compressor. The heat pump using this control system is thus capable of transmitting sufficient heat energy immediately after start of the operation of the heat pump.

Abstract: A copying apparatus equipped with a brushless DC motor for driving a light source, a photoreceptor drum, etc. and including a motor locking circuit for locking the DC motor. The motor locking circuit, when an external force has been applied to a rotor of the DC motor while the DC motor is not being actuated, causes an electric current to flow through a stator coil of the DC motor such that the electric current produces a reaction force counteracting the external force.

Abstract: This invention relates to closure retention apparatus for automatic doors, and more particularly to an electrical circuit for providing a reduced amount of electrical power to the motor which controls the opening and closing of the door. The circuitry includes first circuit means for applying a first level of power temporarily to said motor for operating the door from open toward closed position, and a second circuit for applying a second, reduced level of power continuously to the application of the first level power thereto for a preselected period of time for operating said door toward closed position also.

Abstract: A motor drive assembly includes a stationary housing, a shaft rotatably carried by the housing for driving a load, a gear box rotatably carried by the shaft, and an electric motor in the gear box having a rotor coupled by a gear train to the shaft. A switch in the housing near the gear box is operated when the gear box rotates against a spring bias in response to the rotor's exerting an increased predetermined torque. The motor may have an auxiliary winding in circuit with the switch to reduce power consumed by the motor when the switch is operated. Alternatively, a solenoid may be connected to the switch to hold the rotor stationary when the motor stops. The motor may have a main drive winding which is de-energized by the switch.

Abstract: A motor driving circuit apparatus for use in a motor actuator for actuating, for example, a valve between two limit positions, having a control means for inputting a driving control signal for the motor, a sensor adapted to output a signal corresponding to the position of the actuator, and a comparator section adapted to compare the input through the control means and the output from the sensor, the comparator being adapted to produce an output signal in accordance with which the motor is driven and controlled. The motor driving circuit apparatus comprises a differentiation circuit for differentiating the output of the comparator section and a timer section adapted to be controlled by the output from the differentiation circuit, wherein the driving control of the motor by the output of the comparator section is conducted only within a predetermined period of time in accordance with the output from the timer section.

Abstract: A control system is provided for controlling a flue damper in a furnace flue. The control system includes a voltage source, a thermostat, a gas valve, and means for moving the flue damper between a closed position and an open position. The moving means includes a timer driven by a motor with a specially wound coil assembly including a first winding and a second winding. The coil assembly further includes a first terminal, a second terminal and a center tap terminal. The control system manipulates the flue damper and heating system during three stages of operation. The flue damper is closed and the furnace is off at the beginning of stage one. The control system opens the flue and turns on the furnace during stage one. The flue damper remains open during stage two. The control system turns off the furnace and closes the flue damper during stage three.

Abstract: An apparatus for controlling an AC powered elevator and for improving the safety of the operation of the elevator includes: a three-phase AC power source; a drive device connected to the three-phase AC power source for converting an AC signal into an AC power having a variable frequency, thereby enabling the controlling of an induction motor; a winding induction motor connected to and controlled by the drive device for driving the cage of the elevator; a door induction motor connected to and controlled by the drive device for opening or closing the cage door provided at the cage of the elevator; and a motor control command device having an operation command generator which generates a command for starting or stopping the cage of the elevator so as to control the drive device and a door command generator which generates a command for opening or closing the cage door so as to control the drive device for independently controlling the winding induction motor and the door induction motor.

Abstract: Methods and apparatus for controlling an electric motor effect operation of such motor by electric energization thereof, and derive from a motor winding or from the back electromotive force of the motor an electric signal indicative of motor speed. The motor is thereupon mechanically stalled, and such stalling is detected from a comparison of the derived speed signal and the electric energization. Deenergization of the motor is effected in response to the stalling detected from the latter comparison. Limit switching of electric motors and actuators without limit switches may be provided in this manner.

Abstract: An electric converter motor of synchronous design is used as a hoist by supplying two legs of the stator winding with DC current from a frequency converter to maintain the field during standstill. The converter is connected to the power network.

Abstract: An electric motor having a cage pivotally mounted at one end to a post interior a housing by a first bearing and at its other end by a second bearing between the exterior of the cage and the interior of the housing. A first stator is mounted to the interior of the cage and has an output shaft and first rotor interior thereto. A second rotor is mounted to the exterior of the cage and interior a second stator which is mounted interior the housing. The second stator is driven with a control signal which is a function of the measure reaction torque experienced by the first stator to produce a counter torque to balance the reaction torque. A consistency transmitter mounted on the output shaft produces torque on the first stator as a function of the consistency of the material in which it is rotated.

Abstract: An electric motor having a first rotor on an output shaft, a first stator pivotally mounted to a housing, a second rotor mounted to the first stator and a second stator mounted to the housing. The second stator is driven with a control signal which is a function of the measure reaction torque experienced by the first stator to produce a counter torque to balance the reaction torque. A consistency transmitter mounted on the output shaft produces torque on the first stator as a function of the consistency of the material in which it is rotated.

Abstract: A motor heating control for retrofit applications has an enclosure with power supply terminals and motor heating output terminals. Inside an upper compartment is a first two-pole isolating switch which couples power from the supply terminals through a step-down transformer and a rectifier to one side of a motor heating contactor in the lower compartment. The other side of the motor heater contactor is coupled through fuses and a second two-pole isolating switch in the lower compartment to the motor heating output terminals. An operating handle outside the lower compartment is mechanically interlocked to both isolating switches so that the door of the enclosure cannot be opened without disconnecting both the motor heating power source and the electrical motor from the motor heating control. The motor heating contactor is also electromechanically interlocked to the door interlock mechanism so that the operating handle cannot be moved to its open position until the motor heating contacts are opened.

Abstract: Apparatus and method for high slip operation of an AC electric motor at substantially zero rotation and substantially zero torque in an AC electric motor drive system is disclosed. The electric motor produces a rotation in response to an outgoing signal, such as a drive current, of variable magnitude and frequency supplied by the drive system. An idle control signal is furnished when the drive system is in a substantially zero rotation and substantially zero torque state, where the frequency of the current is approximately zero. The idle control signal causes substantially simultaneously an adjustment of the magnitude of the current to a predetermined magnitude level and a rapid raising of the frequency of the current to a higher frequency value to produce per-unit slip s=(n.sub.1 -n)/n.sub.b greater than 0.1, where n.sub.1 is the synchronous rotation of the stator field of the motor, n is the rotation of the rotor of the motor, and n.sub.b is the synchronous speed of the stator field at motor rated rpm.

Abstract: A fixed gating sequence apparatus and method for an inverter is disclosed. In one aspect of the invention, an outgoing signal of variable frequency is generated by the inverter in response to gating signals provided by an inverter control. The gating signals effectively are provided by a shift register of an inverter control to the gates of the conduction controlled rectifying devices in the inverter in response to a clocking signal. The clocking signal is provided to the clock input of the shift register at a normal system rate when an idle condition (idle control signal) is not present and at a predetermined cycling rate from when the idle condition occurs until a desired fixed gating pattern effectively is provided by the shift register to the inverter. The shift register remains at the stage providing the desired fixed gating pattern until the idle condition no longer is present, whereupon the normal clocking signals are again provided to the shift register.

Abstract: An automatic door closer providing for use as a light duty door opener and having a slip clutch for protecting the electric gear drive power unit from damage due to overspeeding on excess loads applied by overriding manual door operation. Zener diodes across the power supply to the electric drive motor effectively throw a heavy electrical load on the motor and cause the clutch to slip if the motor is sufficiently oversped and caused to act as a higher voltage bucking generator, as by manually forcing the door substantially faster in the direction in which it is being driven. A direct current motor is used at considerably lower than its rated voltage so that electrical power may be safely applied continuously for holding the door closed with the motor stalled, and without the clutch slipping, with the clutch set to slip only when the force applied thereto is significantly higher than the force required to stall the motor yet safe for the drive unit.

Abstract: An SCR is connected across one of three line contacts which couple the power lines to the windings of an a.c. motor. When the line contacts are opened to shut down the motor, heating current is applied to one of the motor windings through the SCR to raise its temperature above the ambient dew point. The SCR is fired every cycle of the line current and the firing angle is controlled in response to a command signal to provide the proper amount of heating current in the motor winding. The command signal is generated by summing a preselected reference signal with a negative feedback signal which is indicative of the amount of motor heating.

Abstract: A motor heat control circuit is provided for heating an electrical motor during the time of motor shutdown, with the circuit functioning to interconnect a winding of the motor with a source of alternating current voltage for substantially an entire half-cycle of the alternating current voltage but only at intervals comprising a selected plurality of cycles of the alternating current voltage. In its preferred form, the motor heat control circuit is adapted to be connected in shunt circuit with a main motor contactor normally interconnecting the motor winding with the source of alternating current voltage, and includes a controllable semi-conductor switch controlled by digital counting logic which is responsive to clock pulses developed from the alternating current voltage.

Abstract: An electromagnetic damping mechanism for a force motor comprising a drive coil, a damping coil, and static coils located about the drive and damping coils to offset the self-induction occurring in the two coils, so that a voltage proportional to the velocity of motion can be induced in the damping coil.

Abstract: An antenna rotator of the type including a first remote drive motor for rotating a remote shaft and a control unit including a second motor for driving an indicator-control member into alignment with a preselect member is described. Self-synchronization and de-energization of the two motors is provided herein when the shaft has been rotated to an end stop position and the indicator-control member is not in alignment with the preselect member. This self-synchronization and de-energization is achieved by sensing the increased current levels caused when the first motor is prevented from rotating by the end stop to apply the energizing potentials being applied to the first motor directly to the second motor whereupon the indicator-control member is aligned with the preselect member and both motors are de-energized.

Abstract: An apparatus is disclosed for generating a non-oscillating torque wherein a magnetic induction torquer having a first coil for clockwise torque and a second coil for counter-clockwise torque is utilized. The coils are selectively driven from a constant current source by way of an assembly of switches and associated precision dummy load impedances. A control circuit is driven by a torque command signal and a clock signal to selectively apply a plurality of control signals to the assembly of switches to cause current pulses to be directed to the appropriate coil or coils of the torquer in order to produce the commanded torque with no oscillating component in the resultant torque.