Provided is a rotary tool. In the rotary tool, the rotating tip tool is mounted on a spindle by the fixture, and the spindle and the tip tool are rotated by a motor. The rotary tool has a switch which can switch the motor between a rotation state and a stop state, and a control device which controls the rotation of the motor corresponding to the operation of the switch. When the switch is turned off after a required time T elapses after the motor is started, the control device stops the rotary tool (104d, 106d) by performing a common braking operation on the spindle, and when the switch is turned off before the required time T elapses after the motor is started, the control device stops the tip tool (101d) by inertia without applying a braking force.

In some examples, a controller device includes processing circuitry configured to determine an alpha voltage and a beta voltage based on time durations for control signals for power-conversion circuitry that drives an electric motor including a rotor. In some examples, the controller device also includes a flux estimator configured to estimate a speed of the rotor and an angle of the rotor based on the alpha voltage and the beta voltage.

A method and a device for controlling an electric motor (9), in particular for moving an endodontic instrument. The device has a first sensor (8) and a control unit (2). The control unit (2) has a drive unit (4), a second sensor (6) and a processing unit (3). The processing unit (3) is configured to cause the endodontic instrument (7) to perform a sequence of movements (M1, M2). The sequence of movements (M1, M2) includes a continuous forward movement (M1) and at least one alternating movement (M2). The sequence may include an additional alternating movement (M3) and/or a reverse movement (M4). The number and order of movements to be performed in a sequence depends on a set of predefined threshold values reflecting the torque load applied to the instrument, as measured by one of the sensors.

A variable pressure sprayer is provided having a housing on which is mounted a battery, a battery-operated motor, and a motor-operated liquid pump, a tank communicating with the pump for holding a supply of liquid, a liquid outlet from the pump to a connector adapted to receive a hose, and an applicator wand adapted for connection to the hose for directing fluid under pressure to a desired target. A trigger is positioned on the applicator wand adapted to switch between a closed flow position and an open flow position. A variable pressure controller is positioned on the housing and connected to the motor for varying output pressure percentage of the pump.

A power tool, such as a drilling power tool, configured to perform an easy hole start operation upon actuation of a trigger. When the trigger is actuated, the motor is driven at a low speed value. The motor speed is increased to a second speed value during a predetermined time threshold and then driven at the second speed value until the trigger is no longer actuated. In some embodiments, the easy hole start operation may be implemented by an easy hole start switch. In some embodiments, if the easy hole start operation persists for a time greater than a predetermined time threshold, then the motor will shut off.

A power tool, such as a drilling power tool, configured to perform an easy hole start operation upon actuation of a trigger. When the trigger is actuated, the motor is driven at a low speed value. The motor speed is increased to a second speed value during a predetermined time threshold and then driven at the second speed value until the trigger is no longer actuated. In some embodiments, the easy hole start operation may be implemented by an easy hole start switch. In some embodiments, if the easy hole start operation persists for a time greater than a predetermined time threshold, then the motor will shut off.

Power tools described herein include a tool output, a motor driving the tool output, a battery pack interface, a power switching network coupled between the battery pack interface and the motor, and a controller coupled to the power switching network to control operation of the motor. The controller is configured to operate the motor at a no-load speed at startup and detect a load state of the power tool. The load state indicates whether the power tool is in a loaded state or an unloaded state. The controller is also configured to incrementally ramp up a speed of the motor from the no-load speed to a selected speed when the power tool is in the loaded state and incrementally ramp down the speed of the motor from the selected speed to the no-load speed when the power tool is in the unloaded state.

Power tools described herein include a tool output, a motor driving the tool output, a battery pack interface, a power switching network coupled between the battery pack interface and the motor, and a controller coupled to the power switching network to control operation of the motor. The controller is configured to operate the motor at a no-load speed at startup and detect a load state of the power tool. The load state indicates whether the power tool is in a loaded state or an unloaded state. The controller is also configured to incrementally ramp up a speed of the motor from the no-load speed to a selected speed when the power tool is in the loaded state and incrementally ramp down the speed of the motor from the selected speed to the no-load speed when the power tool is in the unloaded state.

A blender power unit (BPU) for use in fracturing jobs. The BPU comprises a transformer having an input and an output and configured to receive electrical power via the input at a first voltage to output electrical power via the output at a second voltage; a motor power bus coupled to the output of the transformer; a motor starter bus; at least one motor soft starter having an input coupled to the motor power bus and having an coupled to the motor starter bus; a plurality of electric power relays coupled to the motor power bus and configured to supply electric power from the motor power bus to a load when in a closed state; and a plurality of start electric power relays coupled to the motor starter bus and configured to supply electric power from the motor starter bus to a load when in a closed state.

A method for determining a resonance frequency of a mechanical system including an electric motor coupled to a mechanical load. The method includes starting the motor by providing a supply voltage using a motor controller, and once the electric motor is running at a predefined target rotational speed, applying a first excitation signal comprising a voltage pulse superimposed to the supply voltage. The method further includes measuring a mechanical response of the mechanical system, using a measurement system coupled to the motor, and analyzing the measured response, to determine at least one resonance frequency of the mechanical system.