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.

The present invention provides an abnormality diagnosis system capable of identifying an abnormality occurrence site in a rotary electric machine by use of output of sensors mounted to a bearing of the rotary electric machine. The abnormality diagnosis system includes: a rotary electric machine that has a main shaft secured to a center of a rotor and supported by a bearing; a vibration sensor that measures a vibration value of the bearing; a speed sensor that measures a rotational speed value of the main shaft; and an abnormality diagnosis apparatus that diagnoses abnormality in the rotary electric machine based on the vibration value and the rotational speed value. The abnormality diagnosis apparatus includes: a database that records the vibration value, the rotational speed value, and measurement times of the vibration value and the rotational speed value, as a data group of one unit, the vibration value and the rotational speed value measured within a predetermined time period; and an abnormality determination section that makes determination of abnormality, if a first threshold is exceeded by a difference in maximum vibration value in one speed range of interest between a past data group and a newer data group of a plurality of data groups recorded in the database, and makes no determination of abnormality, even if the first threshold is exceeded by a difference in maximum vibration value outside the speed range of interest.

The present invention provides an abnormality diagnosis system capable of identifying an abnormality occurrence site in a rotary electric machine by use of output of sensors mounted to a bearing of the rotary electric machine. The abnormality diagnosis system includes: a rotary electric machine that has a main shaft secured to a center of a rotor and supported by a bearing; a vibration sensor that measures a vibration value of the bearing; a speed sensor that measures a rotational speed value of the main shaft; and an abnormality diagnosis apparatus that diagnoses abnormality in the rotary electric machine based on the vibration value and the rotational speed value. The abnormality diagnosis apparatus includes: a database that records the vibration value, the rotational speed value, and measurement times of the vibration value and the rotational speed value, as a data group of one unit, the vibration value and the rotational speed value measured within a predetermined time period; and an abnormality determination section that makes determination of abnormality, if a first threshold is exceeded by a difference in maximum vibration value in one speed range of interest between a past data group and a newer data group of a plurality of data groups recorded in the database, and makes no determination of abnormality, even if the first threshold is exceeded by a difference in maximum vibration value outside the speed range of interest.

A method for controlling curtain position of a curtain assembly includes a motor and a control unit. The motor includes a detection unit for detecting the working current of the motor. When the curtain moves upward and stops, the detection unit detects the working current increases. The detection unit sends a signal to a processor of the control unit to judge that the curtain reaches the upper-most position. Then the control unit stops the motor and demands the motor to operate reversely a range to lower the curtain slightly. The curtain that is lowered by operating the motor reversely is defined as at a limited position. When the curtain is lowered by the motor, the lower-most position of the curtain is defined by a pre-set number of revolutions of the motor. The pre-set number of revolutions of the motor is set by the control unit.

A method for controlling curtain position of a curtain assembly includes a motor and a control unit. The motor includes a detection unit for detecting the working current of the motor. When the curtain moves upward and stops, the detection unit detects the working current increases. The detection unit sends a signal to a processor of the control unit to judge that the curtain reaches the upper-most position. Then the control unit stops the motor and demands the motor to operate reversely a range to lower the curtain slightly. The curtain that is lowered by operating the motor reversely is defined as at a limited position. When the curtain is lowered by the motor, the lower-most position of the curtain is defined by a pre-set number of revolutions of the motor. The pre-set number of revolutions of the motor is set by the control unit.

The present invention relates to a control system (10) for an electric machine (EM), for producing a braking torque, by means of the electric machine (EM), in a traction drive, said system comprising a control device (SE), the control device (SE) being configured to control a generator voltage or a generator current in or through a power electronics system (LE) of the electric machine such that during a movement of the traction drive, the electric power (Pel) of the electric machine (EM) can be limited to a level at least below a predefined minimum value.

The present invention relates to a control system (10) for an electric machine (EM), for producing a braking torque, by means of the electric machine (EM), in a traction drive, said system comprising a control device (SE), the control device (SE) being configured to control a generator voltage or a generator current in or through a power electronics system (LE) of the electric machine such that during a movement of the traction drive, the electric power (Pel) of the electric machine (EM) can be limited to a level at least below a predefined minimum value.

A motor control system for a folding partition includes a data storage device and processing circuitry. The data storage device is configured to store a normal threshold profile to serve as a threshold for a measured current supplied to a motor to detect abnormal operation of the motor. The motor is configured to drive motion of the folding partition. The processing circuitry is operably coupled to the data storage device. The processing circuitry is configured to generate an adjusted threshold profile to serve as a threshold for the measured current supplied to the motor while moving the folding partition during a transition from an abnormal operational mode to the normal operational mode. The adjusted threshold profile is used for detecting additional abnormal operation of the motor. The processing circuitry is configured to generate the adjusted threshold profile by adjusting at least a portion of the normal threshold profile.

A motor control system for a folding partition includes a data storage device and processing circuitry. The data storage device is configured to store a normal threshold profile to serve as a threshold for a measured current supplied to a motor to detect abnormal operation of the motor. The motor is configured to drive motion of the folding partition. The processing circuitry is operably coupled to the data storage device. The processing circuitry is configured to generate an adjusted threshold profile to serve as a threshold for the measured current supplied to the motor while moving the folding partition during a transition from an abnormal operational mode to the normal operational mode. The adjusted threshold profile is used for detecting additional abnormal operation of the motor. The processing circuitry is configured to generate the adjusted threshold profile by adjusting at least a portion of the normal threshold profile.

A motor control system includes a drive unit, a backup control unit, and a power unit. The drive unit is electrically connected to the power unit, and is configured to convert a received low-voltage drive signal into a high-voltage drive signal and output the high-voltage drive signal to the power unit. The power unit outputs, according to the high-voltage drive signal, a power supply drive signal provided by a high-voltage battery. The power supply drive signal is configured to drive a motor connected to the power unit to rotate. The backup control unit is electrically connected to the drive unit. The drive unit is configured to output a diagnosis signal indicating a running status of the drive unit to the backup control unit.