Abstract: An apparatus is disclosed which controls the speed of a motor driving a load. A speed controller finds the difference between a command speed value of the motor and a detected speed value of the motor and generates a command current value of the motor on the basis of the difference. A current controller controls current in the motor on the basis of a difference between a command current value received from the speed controller and a detected current value. A torque detector is mounted on the shaft, whereby the motor is connected to the load, for detecting torque acting on the shaft, and an adder adds the detected torque signal detected by the torque detector to the command current value received from the speed controller, the torque detection signal being a correction signal for controlling acceleration torque of the motor.

Abstract: A controlling apparatus for use in a balanced work or cargo handling system which aims at detecting the weight of the work or cargo suspended accurately even if a drift occurs in an acceleration detector due to changes in ambient temperature to thereby enable a stable work or cargo raising and lowering operation to be achieved. The controlling apparatus comprises an acceleration correcting arithmetic unit (23) adapted to output the difference between an averaged acceleration signal (Va.phi.) obtained by averaging the drifted acceleration signals (Va) transmitted by an acceleration; detector (8) during a predetermined period of time and the drifted acceleration signal (Va), as a corrected acceleration signal (Va') to a command arithmetic unit (17) and a load storage and arithmetic unit (22) when the absolute value (.vertline.Va.vertline.) of the drifted speed signal (Va) is less than a preset value (.epsilon.a) and the absolute value (.vertline.V.vertline.

Abstract: An AC variable speed drive (VSD) system having a brushless doubly-fed motor receives power from an electric power grid at a system frequency of the grid and drives a mechanical load. The motor has a rotor with rotor windings and a stator with stator windings comprising first and second polyphase stator systems. The first stator system receives power from the grid at the system frequency. A sensor senses a parameter of the received power by the drive and produces a corresponding power sensor signal. A VSD controller receives and processes the power sensor signal and a reference signal which has been established according to a desired motor operation strategy, and generates therefrom a controller signal. A converter, such as a power electronic converter, receives and converts power from a converter powThis invention was made with government support under Grant No. 79-85BP24332, awarded by the Bonneville Power Administration. The United States government has certain rights in this invention.

Abstract: A system and method of controlling an electronically commutated motor (ECM) driving a blower to maintain the mass flow rate of the blower at a desired value. A microprocessor-based controller unit derives a motor control signal from just two inputs, namely the desired mass flow rate and a speed feedback signal representing the actual shaft speed of the ECM.

Abstract: A control system for a washing machine which controls an induction motor to generate an optimum torque in accordance with a load amount of laundry and whether the washing machine is operating in a washing or drying mode. The control system drives the motor at an optimum torque by varying the input voltage in accordance with the sensed load and sensed mode of operation. This allows a washing machine according to the invention to operate more efficiently and with less noise than conventional washing machines.

Abstract: Method and apparatus for operating a vacuum cleaner in which by detecting a rotational speed of a variable speed fan motor adapted to give a suction force to the cleaner and its change range, the choking state of the filter and the state of the cleaned surface are discriminated, and a speed command of the fan motor is corrected on the basis of the result of the discrimination, and the comfortable cleaning can be performed by the optimum suction force.

Abstract: Method of controlling at least one electric motor on an offset printing machine by inputting a set point for the rotational speed, which comprises forming a set point for the rotational speed by means of a device for controlling the electric motor, and reducing the value of the set point as a function of a measured line voltage when the line voltage is inadequate.

Abstract: A motor torque control assembly is provided which can automatically adjust the motor torque so that its reaction torque remains substantially constant, and so that the reaction torque is not changed by changes in motor internal variables, such as bearing drag, current loop tolerances, motor drag, speed change, and temperature change. Such assembly includes a motor subassembly and a feedback subassembly. The motor subassembly has torque input signal means, a summer unit, a compensator unit, a current loop unit, a motor unit, and a torque output means. The feedback subassembly has torque output sensing means connected to the torque output means for measuring the reaction torque value and connected to the summer unit for measuring the difference of the reaction torque value from a motor torque value of the torque input signal means.

Abstract: A blower motor drive control circuit is configured to maintain a fixed value of motor driving current to maintain a constant amount of air supply from an air conditioner regardless of changes in the amount of intake air.

Abstract: In a circuit arrangement for the timed control of semiconductor switches (1-4) to each of which a freerunning diode (D1-D4) is connected in parallel and which are arranged in branches of a bridge, an ohmic-inductive load (5) of low loss power which lies in the diagonals of the bridge is to be acted on by a controlled average current value. For this purpose two semiconductor switches (for instance 1, 4) lying diagonally opposite each other in the bridge are closed in a current-application phase while in the following freerunning phase a freerunning current flows through the load. For the reduction of the loss power, at the start of the freerunning phase only one (1) of the two diagonally opposite semiconductors (1,4) is opened and a semiconductor switch (3) which lies in the bridge alongside the conductive semiconductor switch (4) is then closed.

Abstract: A centrifuge instrument has a vacuum pump responsive to a rotor recognition arrangement. The pump is operative to provide a predetermined pressure level in the chamber compatible with which one of a plurality of rotors is mounted within the chamber. The requested angular velocity can also be used to control the pressure level in the chamber.

Abstract: An electromagnetic servo device (200) includes a driving control circuit (100), for an electric motor (20) for producing auxiliary torque to be applied to an output shaft (4). A control signal (Va) is provided to thereby supply an armature current (Io) of a controlled quantity, in a controlled direction of conduction thereof, in accordance with a detection signal (Vr, Vl) from a detection mechanism (13). The detection mechanism detects a phase difference (dP) between an input shaft (1) and the output shaft (4). The rotation speed (N) of the electric motor (20) is controlled with the control signal (Va), and is proportional to the quantity of the phase difference (dP).

Abstract: A speed control device for d-c motors includes an IC control circuit having such a construction that a reference voltage is generated across two of its terminals C and D. Additionally, a current proportional to the armature current of the d-c motor is kept flowing in the terminal D at all times. A transistor is connected across the terminals C and D of the control circuit so that motor revolution can be changed linearly by means of a variable resistor connected in parallel across the base and collector of the transistor. With this arrangement, the revolution of d-c motors can be accurately controlled.

Abstract: An apparatus and method of protecting a centrifuge from rotor overspeed and resultant mishap by computation of the rotor moment of inertia is disclosed. In the preferred embodiment, a centrifuge is driven by a rotor mounted on a shaft which shaft is in turn driven by a constant current motor. A tachometer for detecting angular velocity of the drive shaft is used. A desired and ultimate centrifuge operating speed is selected by the operator. The times at which the rotor passes through discrete speeds are recorded and from the time difference the moment of inertia is computed. The moment of inertia can thereafter be utilized to discretely identify or "finger print" rotors to disqualify certain rotors from use in particular centrifuge protocols and establish gross limits of centrifuge operating speed.