788results about "Dc motor starters" patented technology

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).

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.

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.

Disclosed herein is a method and system for initializing a rotating device such as an electronically commutated electric machine. The system comprises: an electric machine; a position sensor subsystem operatively connected to the electric machine configured to measure a position and transmit a position signal to a controller. The controller executes a method initializing position for the electric machine, the method comprising: establishing a sensor subsystem datum indicative of a measurement reference point for a sensor subsystem; obtaining a calibration value corresponding to a distance to a selected magnetic reference position for the electric machine, relative to the sensor subsystem datum; and measuring a position and calculating a position delta relative to an initial reference. The method also includes: estimating an offset from the sensor subsystem datum to an initial reference; determining an absolute position estimate of the electric machine relative to the magnetic reference position. The absolute position estimate is responsive to the calibration value, the position delta, and the offset from the sensor subsystem datum to the initial reference.

An excitation circuit for a flux switching motor. The circuit includes a low-value film capacitor across the DC side of a bridge rectifier. A plurality of electronic switches are arranged in an H-bridge configuration for switching current flow through an armature winding of the motor in accordance with a PWM control scheme and single-pulse control scheme controlled by a microcontroller. A start-up diode is placed across the field winding of the motor and is electronically switched out of the circuit after a startup phase of the motor has completed. The circuit implements armature energy recirculation through the field winding during startup to promote more uniform and quicker startup of the motor. The use of a film capacitor improves the power factor of the circuit, helps to eliminate the introduction of harmonics into the AC voltage source, and helps in mitigating EMI. Reverse commutation is used to bring the motor to a quick stop when it is powered off.

A control apparatus for a brushless DC motor that rotatably drives the brushless DC motor including a rotor having a permanent magnet, and a stator having stator windings of a plurality of phases that generate a rotating magnetic field for rotating the rotor, by a current passage switching device constituted by a plurality of switching elements and performing successive commutation of current to the stator windings. The control apparatus includes: an angular error calculation device for calculating a sine value and a cosine value of an angular difference between an estimated rotation angle with respect to the rotation angle of the rotor and an actual rotation angle, based on a line voltage that is a difference between phase voltages of the plurality of phases on an input side of the stator winding and phase currents of the plurality of phases; and an observer for calculating the rotation angle of the rotor based on the sine value and the cosine value of the angular difference.

A computer system includes a first heat generating element in which a heat generation amount is changed, a second heat generating element, a fan configured to cool the first and second heat generating elements, a first temperature sensor configured to detect a temperature of the first heat generating element, a second temperature sensor configured to detect a temperature of the second heat generating element, and a controller configured to control a rotation speed of the cooling fan, based on the temperatures detected by the first and second temperature sensors.

A solid state controller is provided for a winch and includes fault detection for several parameters and overload interrupt controlled by the controller. The system uses a single controller that can be programmed for several different products and utilizes MOSFET switches for alternating the direction of current

An electric power steering removes external wiring connecting between an electric motor and a control unit, whereby the influence of radiation noise caused by a PWM operation can be reduced. In addition, the heat radiation and assemblability of the electric motor and the control unit can be improved, while achieving high power output. A housing 64 with a metal substrate 61 fixedly secured thereto is arranged at a side opposite to an electric motor 30. The cooling fins are formed on an outer side of a housing 64 and on an outer side and an inner side of a cover 65. A metal substrate 61, a large current substrate 62 and a control substrate 63 are arranged inside of the housing 64 and the cover 65 in a laminated structure.

The invention relates to a method for operating a handheld electric power tool, having an electric motor that is drivable at a rated torque as the maximum allowable motor torque by the application of a maximum allowable motor current. The method includes the steps of manually furnishing a specification of a maximum torque, in which the maximum torque is within a setting range between a minimum set torque and the rated torque, operating the electric motor by applying a motor voltage which corresponds to an rpm desired by the user, and limiting the motor current to a current value that depends on the furnished specification of the maximum torque.

The invention also related to a drive unit for an electric power tool, which includes an electric motor drivable at a rated torque as a maximum allowable motor torque by application of a maximum allowable motor current. A setting element manually furnishes a specification of a maximum torque, the maximum torque being within a range between zero and the rated torque. A triggering unit operates the electric motor by applying a motor voltage that corresponds to an rpm desired by the user. A motor controller limits the motor current to a current value that depends on the furnished specification of the maximum torque.

Disclosed is a method and device for controlling the startup of a synchronous reluctance motor. The device includes: a voltage injector which generates injection voltages to estimate an initial position of the rotor; a motor drive voltage generator which converts stationary-coordinate-system voltages including the injection voltages to three-phase motor drive voltages and applies the three-phase motor drive voltages to the motor; a current extractor which extracts response current components i_α-inj, i_β-inj in respect to the injection voltages from two-phase stationary-coordinate-system currents converted from three-phase currents detected upon rotation of the motor; and a position/speed estimator which extracts response current components related to a rotor position from the response current components i_α-inj, i_β-inj in respect to the injection voltages to calculate a rotor position error (e), and estimates the speed and position {tilde over (ω)},{tilde over (θ)} of the rotor from the calculated rotor position error (e).

A motor drive control device and motor startup method prevent startup noise and reduce startup time. At startup, a current to which a rotor does not react is passed through two phase coils of a polyphase DC motor in succession, and a voltage polarity induced in a non-conducting phase is detected. A first operation decodes the detected signal, and determines phase coils of the motor through which a current should pass to rotate the rotor and the energization direction. A second operation forms a control signal for passing a current according to the determination to drive the motor, detects a voltage peak induced in the non-conducting phase during the drive, and performs switching control of a conducting phase. In normal operation, the position of the rotor is detected based on a back EMF in each phase, and rotation control is performed.