Abstract: When the current flowing through each electric terminal of an AC motor 21 reaches the vicinity of zero, an operation putting the electric terminals of the AC motor 21 into an opened state, or putting an electric terminal into a conductive state via a reflux diode inside an inverter 11, is carried out. Herein, as an operation such that the current flowing through each electric terminal reaches the vicinity of zero, the electric terminals are short-circuited by all upper arm or lower arm switching elements of the inverter 11 being turned on. By so doing, a flow of electromagnetic energy of a reactance component of the AC motor 21, from the AC motor 21 into the inverter 11 side when the drive of the inverter 11 is stopped, is prevented or suppressed. As a result of this, an overvoltage or overcurrent is prevented.

Abstract: A driver circuit includes a first current source configured to sink part of the current from a power supply through a load and a second current source configured to sink part of the current from the power supply to a return path, bypassing the load, so that the current through the load is the difference between the current from the power supply and the current through the second current source.

Abstract: A loss-less snubber drive for a permanent magnet motor. The motor system includes a first motor phase with a primary winding and an auxiliary winding. A controllable switch is positioned between the primary winding and ground such that current passes through the primary winding to ground when the controllable switch is closed. A capacitor is configured to accumulate charge when the controllable switch is opened. The auxiliary winding is configured such that charge stored by the capacitor causes current to pass through the auxiliary winding when the controllable switch is closed.

Abstract: An inverter, particularly for supplying energy to a three-phase motor (3) of a motor vehicle, where the inverter comprises a half bridge (1a, 1b, 1c) for electrically connecting to the three-phase motor (3). The half-bridge (1a, 1b, 1c) comprises a short circuit element (8) which is electrically conductively connected to an input (6b) and an output (6c) of a power semiconductor switch (5a; 5b) of the half bridge (1a, 1b, 1c). The short circuit element generates a short circuit, between the input (6b) and the output (6c) of the power semiconductor switch (5a; 5b), depending on the voltage value of a voltage present between the input (6b) and the output (6c) of the power semiconductor switch (5a; 5b).

Abstract: To provide a power supply device which can reduce energy loss caused due to the forward-direction voltage of a flywheel diode. In a load circuit for subjecting an electronic switch T1 provided between a DC power supply VB and a motor M1 to the PWM control to thereby drive the motor M1, a MOSFET (T2) is provided in parallel to the motor M1. A parasitic diode Dp of the MOSFET (T2) is provided in a manner that its forward direction is in opposite to the flowing direction of a load current ID. The MOSFET (T2) is turned on during a part of a period during which the electronic switch T1 is placed in an off state to thereby flow a circulation current flowing through the motor M1 into the MOSFET (T2). Thus, the energy loss can be remarkably reduced as compared with the case of using the flywheel diode.

Abstract: A conveyor unit (2) including a driving roller (5), a motor (30) for powering the driving roller (5), and a controller (10) adapted to adjust the motor (30) so as to control the driving roller (5), the motor (30) including a permanent magnet and an armature having a plurality of armature coils (32a–32c), and the controller (10) having an interrupter (15) adapted to repeat shunting and deshunting of at least one of the coils (32a–32c) and a rotation detector (17) adapted to detect an externally forced rotation of the motor (30) in response to an electromotive force induced in at least one of the coils (32a–32c), wherein in the case that the motor (30) is not driven, the controller (10) maintains operations of the interrupter (15) and outputs a presence signal by determining conveyance of an article (W) into an area powered by the motor (30) upon detection of the rotation of the motor (30) by means of the rotation detector (17).

Abstract: A retarded electric motor designed as a series motor or an asynchronous motor having a squirrel cage rotor. A valve is provided for switching between motor operation and braking operation. During motor operation the motor is operated in a known configuration as series motor or as asynchronous motor. If configured as a series motor, the valve (S1, S2, S3) allows to bypass the armature and to operate the motor as an externally excited direct current generator when switching into braking operation. If configured as an asynchronous motor, a switch is utilized to disconnect at least two field windings from mains. A valve is utilized to excite the motor externally from mains with a pulsating direct current during braking.

Abstract: An on-vehicle rotary electric apparatus, such as an on-vehicle generator, is provided. The apparatus comprises a stator having multi-phase windings, a rotor driven to rotate by either an on-vehicle motor or the running drive shaft of a vehicle, and a driving member for driving the field winding. The rotor has a field winding producing a magnetic field. The driving member drives the field winding by supplying the exciting current thereto and changing the exciting current so that the magnetic field rotates differently in a rotation speed from the rotor. Specifically, the driving member comprises a short-circuit winding wound around part of magnetic poles of the rotor and a current-supply unit for supplying, as the exciting current, a single-phase alternating current to the field winding. The short-circuit winding produces a magnetic field delayed in phase by 90 degrees compared to the magnetic field produced by the rotor.

Abstract: A system is provided for controlling a DC motor which is constructed to propel a golf car. The motor is a shunt wound motor having independently excited armature and field windings. The basic input to the armature of the motor is supplied through a pulse modulated chopper circuit which varies the width of the pulse in response to the throttle of the golf car. Full control of the input to the field winding is gained by the supply of power to an H bridge circuit. Armature current is continuously sensed to provide an indication of the status and performance of the car during operation. At a predetermined level of armature current the field current is adjusted to provide a higher torque at a specific speed. When armature current indicates a predetermined overspeed condition, field current is adjusted to enhance regeneration and the resultant braking. In addition, the stopped condition is continuously monitored.

Abstract: A system is provided for controlling a D-C motor which is constructed to propel a golf car. The motor is controlled to provide performance according to a predetermined field current map which calls for a particular performance response to specified performance events. The performance events are detected by sensing actual speed and armature current and the performance response is triggered by adjustment of the field current. A performance map correlating actual speed to various events and specifying the field current response is designed for the motor used. In addition an armature current performance map is similarly constructed correlating armature current to particular performance events.

Abstract: Between one end of a motor coil and the ground, a drive transistor is connected. When the drive transistor is turned off, and in particular at the moment when a current flowing through the motor coil drops to zero, a back electromotive force is induced at said one end of the motor coil. The back electromotive force is clamped by a pnp-type transistor with its base supplied with a constant voltage and its emitter connected to said one end of the motor coil.

Abstract: A system is provided for controlling a DC motor which is constructed to propel a golf car. The motor is a shunt wound motor having independently excited armature and field windings. The basic input to the armature of the motor is supplied through a pulse modulated chopper circuit which varies the width of the pulse in response to the throttle of the golf car. Full control of the input to the field winding is gained by the supply of power to an H bridge circuit. Armature current is continuously sensed to provide an indication of the status and performance of the car during operation. At a predetermined level of armature current the field current is adjusted to provide a higher torque at a specific speed. When armature current indicates a predetermined overspeed condition, field current is adjusted to enhance regeneration and the resultant braking. In addition, the stopped condition is continuously monitored.

Abstract: The process has an open control loop which detects the total current intensity of actuators and supplies it to a microprocessor. In a modulation mode the microprocessor successively generates at its output a modulated set value signal for each actuator, the set value signals lying below the response level of the process. The microprocessor then determines compensation values from the total current signal with which the set values of the actuators are corrected. The (regulating) speed of a control is thus combined with the accuracy of a regulation. The hardware expenditure (costs) is minimized thanks to the total current detection instead of the individual current detection.

Abstract: In a circuit arrangement for influencing the start-up and/or braking behavior of three-phase a.c. non-synchronous motors having phase windings (5, 6, 7), which are connected in star for continuous operation and have terminals for the phase conductors (1, 2, 3) and for a neutral conductor (4) the phase terminal of one phase winding (6, 7) is connected by a change-over switch (9, 11) to the neutral conductor (4) for start-up and/or braking. A corresponding circuit arrangement is disclosed also for three-phase a.c. non-synchronous machines in which the phase windings (5, 6, 7) have terminals for the phase conductors (1, 2, 3) and for a neutral conductor (4).

Abstract: A hard disk drive having a plurality of disks mounted on the rotor of a current limited, electronically commutated dc motor. Windings on the stator of the motor are divided into serially connected run and start sections and first and seconds drive circuits are provided to operate the motor by alternatively enabling the first drive circuit to pass currents serially through the two sections of the winding and enabling the second drive circuit to pass currents through only the run sections of the windings. During spin up of the disk drive to operating speed, the first drive circuit is enabled and the second drive circuit is disabled to drive the disks to the speed at which the back emf limits on the acceleration of the motor using both sections of the windings reduces the acceleration to the maximum acceleration achievable at the current limit using the run sections alone. Spin up is then completed by enabling the second drive circuit and disabling the first drive circuit.

Abstract: This invention relates to an inverse electromotive force eliminating device which protects a motor controller of a motor utilizing a MOS-FET by effectively eliminating the inverse electromotive force generated in a process for accelerating and decelerating a mobile device by utilizing an alternating current servo motor operated by applying the power supply of an inverter. A voltage, generated by an inverse electromotive force upon accelerating and decelerating of a motor in a state when the direct current required for circuit operation is supplied by power supply, increases at an input of an inverter. The voltage is detected by an inverse electromotive force detector and thereafter it is applied to an inverse electromotive force eliminator by utilizing a MOS-FET base driver so that the inverse electromotive force of motor is eliminated. Simultaneously, first and second indicators indicate whether the power supply is inputted and whether the inverse electromotive force is generated.

Abstract: A current limiting impedance network for a dryer control in which a controlled conduction device, such as an SCR, is connected to shunt an AC motor to selectively prevent operation of the motor, in which a current limiting, power dissipating resistor is replaced by a lower value and lower power rating resistor and a capacitor connected in series with the resistor. The capacitor has a capacitive reactance of a value approximately twice the inductive reactance of the motor to provide substantially the same magnitude of circuit impedance as with the current limiting power resistor and cause operation of the circuit with a leading rather than a lagging current phase angle.