A method of operating a power tool having a motor and a controller is provided. The method includes: receiving a position of a variable-speed input mechanism mounted on the power tool; determining a target speed of the motor corresponding to the position of the variable-speed input mechanism; determining an underspeed threshold corresponding to the target speed; determining a rotational speed of the motor; and interrupting a supply of power to the motor if the rotational speed of the motor is less than the underspeed threshold.

Techniques for controlling operations of a motor based on position errors are described. In an example, a user device sends an amount of electrical current to the motor to cause the motor to move. The user device also determines the motor is in position for a time interval despite the amount of electrical current. Based at least one the time interval and the amount of electrical current, the user device determines a position difference associated with a target position and a measured position of the motor during the time interval, and reduces the amount of electrical current based at least in part on the time interval.

Techniques for controlling operations of a motor based on position errors are described. In an example, a user device sends an amount of electrical current to the motor to cause the motor to move. The user device also determines the motor is in position for a time interval despite the amount of electrical current. Based at least one the time interval and the amount of electrical current, the user device determines a position difference associated with a target position and a measured position of the motor during the time interval, and reduces the amount of electrical current based at least in part on the time interval.

A machine tool device for a portable machine tool in one embodiments includes at least one coupling unit which couples a machining tool and at least one drive unit configured to drive the coupling unit. The machine tool device includes a recuperation unit which provides, in at least one deactivated state of the drive unit, electrical energy which supplies at least one functional unit from a kinetic energy of at least the coupling unit.

A machine tool device for a portable machine tool in one embodiments includes at least one coupling unit which couples a machining tool and at least one drive unit configured to drive the coupling unit. The machine tool device includes a recuperation unit which provides, in at least one deactivated state of the drive unit, electrical energy which supplies at least one functional unit from a kinetic energy of at least the coupling unit.

A motor control system configured to detect a pinch condition of a structure actuated by a motor includes a pinch detection module configured to receive a current signal indicative of a motor current, determine a rate of change of current based on the current signal, and generate a pinch signal indicative of the pinch condition in response to either one of the motor current being greater than a current threshold and the rate of change of current being greater than a rate of change threshold. The motor control system further includes a position control module configured to control the motor to actuate the structure in response to an input and at least one of stop and reverse the motor in response to the pinch signal.

A motor control system configured to detect a pinch condition of a structure actuated by a motor includes a pinch detection module configured to receive a current signal indicative of a motor current, determine a rate of change of current based on the current signal, and generate a pinch signal indicative of the pinch condition in response to either one of the motor current being greater than a current threshold and the rate of change of current being greater than a rate of change threshold. The motor control system further includes a position control module configured to control the motor to actuate the structure in response to an input and at least one of stop and reverse the motor in response to the pinch signal.

A blower in one aspect of the present disclosure includes: a housing including a suction port and a discharge port; a motor in the housing; a fan in the housing; a motor drive circuit; and a control circuit. The control circuit detects an insufficient airflow from the suction port to the discharge port based on an operation parameter. The operation parameter is associated with an operation of the motor.

A blower in one aspect of the present disclosure includes: a housing including a suction port and a discharge port; a motor in the housing; a fan in the housing; a motor drive circuit; and a control circuit. The control circuit detects an insufficient airflow from the suction port to the discharge port based on an operation parameter. The operation parameter is associated with an operation of the motor.

A power tool includes a housing, an electric motor, a driver circuit, a speed detection device, and a control device. The driver circuit is electrically connected to the electric motor to drive the electric motor to operate. The speed detection device is configured to acquire a rotational speed of the electric motor. The control device is connected to the speed detection device and the driver circuit and outputs a control signal to the driver circuit to control rotation of the electric motor. The control device is configured to acquire the rotational speed of the electric motor when the electric motor is in a start-up stage, obtain a rotational speed variation of the electric motor within a preset time based on the rotational speed of the electric motor, and turn off the electric motor when the rotational speed variation is less than a rotational speed variation threshold.