Abstract: A method and device for elevator DC drive motor speed control stabilization system in which current data and speed data are used as feed-back information. The current regulator is approximated by an ideal integrator, and mathematical model thereby obtained is used for determining the amplification and time constants of the control system speed loop or loops, and these system parameters are compensated by providing short instruction accentuations for achieving practically delay-free compliance with instructions.

Abstract: A protection circuit for the power transistor of an automotive motor control circuit. The protection circuit comprises a protection transistor, a resistor, and a Zener diode. The emitter-collector circuit of the protection transistor is connected in series with the resistor across the primary conduction path of the power transistor, with the resistor connected across the conduction control terminals of the power transistor. The Zener diode is connected in series with the emitter-base circuit of the protection transistor across the motor, with the Zener diode poled to oppose current flow through the emitter-base circuit. Transient inductive voltage generated across the motor upon removal of an externally applied control signal exceeds the reverse breakdown threshold of the Zener diode and biases the protection transistor conductive.

Abstract: A control system capable of improving a disturbance response characteristic, includes a control processing unit and a power converter. The control processing unit includes apparatus for (a) providing a signal A equal to a predetermined transfer function G.sub.X (s) of a detected value of a controlled variable n, (b) providing a signal B equal to a transfer function [1+G.sub.X (s).multidot.G.sub.LH (s)] of a first command value, and (c) providing, as a second command value, a difference T* between said A and B signals, where G.sub.LH (s) is a simulated transfer function which is from T* to n. The power converter controls the controlled variable according to the second command value.

Abstract: A motor controller with means responsive to a motor condition for preventing termination of power to the motor in response to fault conditions when these fault conditions occur during start-up of the motor.

Abstract: A drive circuit for servomotors that eliminates the need for microswitches to protect the motor when the system is driven to its limits of travel. The circuit monitors the current to the motor, identifies overload currents and terminates current flow to the motor when an overload occurs. The current flow is restored only when a reverse rotation command signal is received by the drive circuit.

Abstract: A control circuit is provided for operating a power switch with an associated resistance, wherein the power switch has conductive and nonconductive conditions and is adapted to apply a driving voltage across an electric load circuit, such as a D.C. motor, when the power switch is in its conductive condition.

Abstract: A window operating system includes a motor control circuit for controlling the operation of direct current permanent magnet motors mounted on window operators associated with each window. Each of the motors on each of the windows is connected to the control circuit only by a pair of wires which both power the motor and provide information to the control circuit as to the status of motor operation. The status of motor operation is determined by monitoring the back electromagnetic force expressed by the motors. To help differentiate back electromagnetic force from supply voltage supplied to the motors, the motors are supplied with full rectified alternating current power, rather than simple direct current, so that the presence or absence of zero voltage between half waves of the voltage expressed across the motors can be monitored to determine the absence or presence of back electromotive force during those time periods.

Abstract: A window operating system includes a motor control circuit for controlling the operation of direct current permanent magnet motors mounted on window operators associated with each window. Each of the motors on each of the windows is connected to the control circuit only by a pair of wires which both power the motor and provide information to the control circuit as to the status of motor operation. The status of motor operation is determined by monitoring the back electromagnetic force expressed by the motors. To help differentiate back electromagnetic force from supply voltage supplied to the motors, the motors are supplied with full rectified alternating current power, rather than simple direct current, so that the presence or absence of zero voltage between half waves of the voltage expressed across the motors can be monitored to determine the absence or presence of back electromotive force during those time periods.

Abstract: An apparatus for protecting machinery driven by electric motors from operating during over-load and light-load conditions, comprising: a current transformer operatively associated with an electrical supply line for the induction motor; a current-voltage transforming circuit for generating a control signal having a magnitude proportional to current flowing in the supply line; an upper limitation magnitude comparator for generating an over-load signal output whenever the magnitude of the control signal exceeds a predetermined upper safety value; a lower limitation magnitude comparator for generating a light-load signal output whenever the magnitude of the control signal is less than a predetermined lower safety level; an inhibitable protection timer for producing a fault persistence output signal whenever one of the over-load and light-load signal outputs is generated for a period of time longer than a predetermined protection time; a steady state timer for inhibiting an enable output signal for a predetermined

Abstract: Disclosed is a monitoring circuit responding to different operational conditions of an electric motor. The circuit includes a measuring resistor connected in series with the stator winding of the motor to produce an actual load value signal. The actual value signal is applied to one input of a comparison circuit whose other input is consecutively supplied with three different nominal reference voltages corresponding to principle operational conditions of the motor, namely to the starting phase, to the normal operational phase, and to an overload. The source of the variable reference voltage includes switching transistor cooperating with a timing member and with voltage dividers adjustable from zero to a maximum nominal voltage value corresponding to the power supply voltage.

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: The counter-EMF generated by electromechanical actuators (14), (16), (18) and (20) during deceleration of the actuators is pooled to power various temperature control devices, such as Peltier-type thermoelectric modules (26) associated with the actuators themselves or a similar thermoelectric module (24) and a fan (30) used to cool an AC-to-DC power converter (10) situated at a location remote from the electromechanical actuators. An electronic commutator circuit (44) is operably coupled to windings (38), (40) and (42), of the actuators to energize the windings to operate the actuators as motors and terminate such energization of the windings to permit deceleration of the actuator whereby it operates as a generator.

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 solid state protection system for AC electric motors driving high inertia loads requiring long acceleration times. An electroresponsive relay (OL) is separately responsive to permissible acceleration time, circuitry (DT, DC), acceleration overload current circuitry (ACA), and to normal running overload current circuitry (ACR). Up-to-speed detector and latch circuits (USD, USL) deactivate the acceleration time circuitry and overload current circuitry, and activate the running overload current circuitry upon attainment of normal running speed by the motor. The response levels of the overload and time response circuits are individually settable.

Abstract: A control circuit for an electrically adjustable patient chair that is adapted when actuated by the momentary depression of a start button, to automatically return the chair to its fully down and tilt forward position. The control circuit includes a multiple-pole relay that is latched in the closed position to energize both motor windings by a solid state switching device that is gated to the on state by a current transformer that senses the load current in a conductor that passes through the core of the transformer. The adjustment motors remain energized until a pair of limit switches are opened upon the chair attaining its exit position. The resulting current drop to zero in the load line is sensed by the current transformer which turns off the solid state switching device which in turn unlatches the relay.

Abstract: Device for controlling a monophase rotary step-by-step motor supplying electric control pulses to the winding of the motor, comprising means for detecting the variation of the current passing through the motor winding at each control pulse, this detection means including means of interrupting the control pulse when a minimum appears in the current passing through the winding.

Abstract: A solid state electronic circuit for protecting a single phase induction motor against excessive loading by comparing motor start winding voltage with motor source voltage is disclosed, wherein the circuit automatically removes the motor from its driving source upon the occurrence of such excessive loading. An additional feature includes comparing start winding voltage with source voltage to remove the motor from its driving source upon the occurrence of excessive start winding voltage and corresponding excessive high motor speed. A motor starting circuit to permit the start winding voltage to rise to its normal running level and a time delay restarting circuit to permit the motor to automatically restart after elapse of a selected lock out period following removal of the motor from the source due to insufficient or excessive loading is also provided.

Abstract: A control system for a compound DC electric motor includes a shunt field winding connected in parallel with a series field winding, with both windings being connected to a power source. A time delay is positioned between the series field winding and the power source for energizing the series field winding a predetermined time period after the energization of the shunt field winding.

Abstract: A device is described for converting solar energy into electric power for a load, which device is provided with photocells and electric accumulators. Switching means are provided which at least during starting of the load connect this load to the output terminals of the array of photocells so that during starting the current through the load is determined by the current supplied by the photocells. The device makes efficient use of the available solar radiation, is of simple design and is reliable.

Abstract: A method and apparatus for connecting a rotary drum drive, particularly a rotary drum drive of a rotary furnace or kiln, after disconnection for a short time, and before standstill of the oscillating drum, features detecting the movement of the oscillating drum and connecting the drive motor at a turning point of the oscillation or upon agreement with the direction of movement and the driving direction.

Abstract: A regulating system for direct current motor control having an inner and an outside loop is prevented from winding up in the outside loop, when the inner loop saturates, by a clamping circuit storing the value of the controlling voltage of the outside loop reached at the moment of saturation and generating an overriding error signal by reference to said stored value for providing effective control after saturation has ended.