2690results about "Ac motor stoppers" patented technology

A method and apparatus for braking a motor has a braking power switching device coupled across windings of the motor. To brake the motor, the braking power switching device is cycled on and off.

A motor controller includes a power source unit providing a direct current output, a drive unit including a drive coil, first and second transistor units, a voltage drop component, and a processor. The transistor units are coupled to the power source unit and the drive unit, and enable electricity to flow through the drive coil in a first direction when the first and the second transistor units are in conducting and non-conducting states respectively, and in an opposite second direction when the first and the second transistor units are in non-conducting and conducting states respectively. The voltage drop component has a first end coupled to the drive unit and a grounded second end. The processor is coupled to a junction of the drive unit and the voltage drop component, and provides first and second pulse-width-modulated signals to the first and second transistor units, respectively.

An electrical hand tool machine (1) having a motor switch (2) configured as a button and a current regulator (4) disposed in the current circuit of an electrical motor (3), having a soft-start input (5), in whose branch current a timing capacitor (6) is arranged. A current-direction-dependent element (7) is arranged between the soft-start input (5) and the capacitor (6).

An electronically-controlled roll-up window shade that can easily be installed by a homeowner or general handyman is disclosed. The motorized shade includes an internal power source, a motor, and a communication system to allow for remote control of the motorized shade. One or more motorized shades can be controlled singly or as a group. In one embodiment, the motorized shades are used in connection with a zoned or non-zoned HVAC system to reduce energy usage. In one embodiment, the motorized shade is configured to have a size and form-factor that conforms to a standard manually-controlled motorized shade. In one embodiment, a group controller is configured to provide thermostat information to the motorized shade. In one embodiment, the group controller communicates with a central monitoring system that coordinates operation of one or more motorized shades. In one embodiment, the internal power source of the motorized shade is recharged by a solar cell.

A wireless operating system (10) utilizing a multi-functional wall station (12) for a motorized door/gate operator includes an operator (50) for controlling the movement of a door/gate (54) between various positions. The system has an operator with a receiver (56) and a wall station transmitter (12) for transmitting a signal (42) to the receiver. The signal initiates separate operator functions in addition to opening and closing of the door/gate. A remote transmitter (70) may send a remote signal (74) received by the receiver, wherein the receiver is capable of distinguishing between the wall station signal (42) and the remote signal (74). The wall station includes a transmitter programming button (24), wherein actuation of the transmitter programming button places the wall station transmitter in a learn mode, and wherein subsequent actuation of the remote transmitter positively identifies the remote transmitter for use with the wall station. A light (66) powered by the operator and a light actuation button (18) provided by the wall station transmitter is included in the system. Actuation of the light actuation button (18) functions to switch the light on or off. A pet height button (22), provided by the wall station transmitter, selectively positions the height of the gate/door (54) from its fully closed position to allow ingress and egress of a pet. A delay-close button (20) closes the door/gate after a predetermined period of time. Actuation of a door installation button (28) sequences the door/gate and said operator through various operational parameters to establish a door operating profile. A keyless entry transmitter (80) and a second wall station may also control the operator.

A variable speed wind turbine having a doubly fed induction generator (DFIG), includes an exciter machine mechanically coupled to the DFIG and a power converter placed between a rotor of the DFIG and the exciter machine. Thus, the power converter is not directly connected to the grid avoiding the introduction of undesired harmonic distortion and achieving a better power quality fed into the utility grid. Moreover, the variable speed wind turbine includes a power control and a pitch regulation.

A permanent magnetically excited electrical rotary drive for a blood pump is proposed, comprising a permanent magnetic rotor and a stator, said stator comprising a drive winding having at least two loops for the production of a magnetic drive field which produces a torque on the rotor, with each loop belonging to a different electrical phase, furthermore comprising a setting device which supplies each loop in each case with a phase current or in each case with a phase voltage as a setting parameter, with the setting device comprising a separate power amplifier for each loop so that the setting parameter for each loop can be regulated independently of the setting parameter for the other loops.

A disk drive is disclosed comprising a disk, a head actuated over the disk, and a spindle motor for rotating the disk, the spindle motor comprising a plurality of windings. Disk control circuitry executes a spin-down operation of the spindle motor by estimating an angular position of the spindle motor by applying a voltage to at least one of the windings and evaluating a rise time of current flowing through the winding. The windings are commutated in response to the estimated angular position, and a driving current is applied to the windings to brake the spindle motor.

A disk drive is disclosed comprising a spindle motor having a plurality of windings including at least a first winding, a second winding, and a third winding. During a spin-up operation, a voltage is applied to the first winding and a first rise time is measured for current flowing through the first winding to reach a predetermined threshold. A voltage is applied to the second winding and a second rise time is measured for current flowing through the second winding to reach a predetermined threshold. A voltage is applied to the third winding and a third rise time is measured for current flowing through the third winding to reach a predetermined threshold. A difference is computed in response to the first rise time, the second rise time, and the third rise time, and an angular position of the spindle motor is estimated by computing an arctangent in response to the difference.

The speed of a fan motor is controlled by varying a DC voltage to the fan motor. A series pass transistor is used to vary the DC voltage to the fan motor. A power management controller sets the fan motor speed by outputting pulses to a pulse-to-DC voltage converter that changes the pulses to a proportional DC control voltage for controlling the series pass transistor. A tachometer output amplifier circuit is used to remove DC components and amplify to useful logic levels a low level tachometer output signal from the fan motor. The amplified tachometer signal is used by the power management controller in controlling the rotational speed of the fan motor.

An apparatus for the thermal regulation of an AC drive for providing power to a motor includes a temperature sensor producing a signal indicative of temperature, a heater resistor connectable across a DC link of the AC drive, and a first switch. A controller is operable to monitor the temperature signal and control the first switch to provide power via the DC link to the heater resistor if the sensed temperature is below a predetermined setpoint.

A powered tool for performing surgical procedures. The tool includes a handpiece in which a power generating unit is housed. A control member is mounted to the handpiece. The control member is mounted to the handpiece so that the orientation of the control member can be selectively set relative to the point to which it is mounted to the handpiece and so it can move relative to a reference point on the handpiece. A control module monitors the orientation of the control member and its position relative to the reference point. Based on the control member orientation and position, the control module generates signals to regulate the operation of the power generating unit. When the power generating unit is a motor, the control module generates signals to ensure that the maximum speed at which the motor can be driven is less than the no load speed.

An electric drive apparatus and method for controlling medium-voltage alternating current motors wherein a multi-phase power transformer having multiple secondary windings provides multi-phase power to multiple power cells which provide four quadrant operation. Each power cell has a single-phase output and is controllable by a modulation controller. The power cells are connected in series thus permitting the maximum output voltage for each cell to be less than the maximum line-to-line voltage. Each power cell can have a rectifier portion to convert input AC-to-DC, capacitors, an output DC-to-AC inverter, a regenerative bridge converter connected in parallel with the rectifier portion and a local modulation controller connected to a master controller.

A system for operating a barrier system such as a garage door, gate or fence. A DC motor is connected to and operates a barrier drive. A power amplifier is configured to receive power signals from a power supply and to output modulated DC signals to the DC motor. A controller implements an intelligent closed-loop motion control algorithm to control the power amplifier according to a non-linear motion profile. A feedback sensor provides status signals to the controller to determine position or speed of the barrier.