A method for controlling an electric motor is described herein. The method includes setting a current limit, a speed limit and a torque limit. The method also includes sensing a DC link current, comparing the sensed DC link current with the current limit and adjusting the torque limit based on the comparison with the current limit to provide an adjusted torque limit. The method also includes sensing the speed of the electric motor, comparing the speed with the speed limit and further adjusting the adjusted torque limit based on the comparison with the speed limit.

Provided for may be a pump failsafe apparatus for use with a pump motor, the pump failsafe apparatus comprising a foot pedal configured to generate a first signal when depressed and a second signal when released. The apparatus may comprise a power supply having an internal logic controlled power switch, the power supply in electrical communication with at least the pump motor, wherein the internal logic controlled power switch includes an active state (ON) and an inactive state (OFF). The apparatus may further include an overspeed detector, an under voltage detector in electrical communication with at least the power supply, the under voltage detector configured to measure a logic voltage, and a pump cartridge detector.

Provided for may be a pump failsafe apparatus for use with a pump motor, the pump failsafe apparatus comprising a foot pedal configured to generate a first signal when depressed and a second signal when released. The apparatus may comprise a power supply having an internal logic controlled power switch, the power supply in electrical communication with at least the pump motor, wherein the internal logic controlled power switch includes an active state (ON) and an inactive state (OFF). The apparatus may further include an overspeed detector, an under voltage detector in electrical communication with at least the power supply, the under voltage detector configured to measure a logic voltage, and a pump cartridge detector.

A fan assembly is provided. The fan assembly includes a fan, a motor that is coupled to the fan, and a variable frequency drive (VFD) that is coupled to the motor. The motor includes a maximum rated speed that is greater than a maximum structural speed limit of the fan, and the VFD includes a current output limit configured to limit an operational speed of the motor to be less than or equal to the maximum structural speed limit of the fan.

A fan assembly is provided. The fan assembly includes a fan, a motor that is coupled to the fan, and a variable frequency drive (VFD) that is coupled to the motor. The motor includes a maximum rated speed that is greater than a maximum structural speed limit of the fan, and the VFD includes a current output limit configured to limit an operational speed of the motor to be less than or equal to the maximum structural speed limit of the fan.

A method for fail-safe rotational speed monitoring of a sensorless three-phase drive, in which the three-phase drive is controlled in three phases with the phases U, V, W by drive electronics comprising an inverter, with the voltage signals at the three phases U, V, W being present as pulse width modulated signals, in which an output frequency of the inverter applied to the drive is determined and an actual rotational speed of the drive is determined therefrom, in which the actual rotational speed is compared with a predeterminable desired rotational speed and in which, if the actual rotational speed exceeds the desired rotational speed, the drive is switched off, the pulse width of the pulse width modulated signals being used to determine the output frequency of the inverter.

A method for fail-safe rotational speed monitoring of a sensorless three-phase drive, in which the three-phase drive is controlled in three phases with the phases U, V, W by drive electronics comprising an inverter, with the voltage signals at the three phases U, V, W being present as pulse width modulated signals, in which an output frequency of the inverter applied to the drive is determined and an actual rotational speed of the drive is determined therefrom, in which the actual rotational speed is compared with a predeterminable desired rotational speed and in which, if the actual rotational speed exceeds the desired rotational speed, the drive is switched off, the pulse width of the pulse width modulated signals being used to determine the output frequency of the inverter.

A drilling tool includes a tool body, a brushless motor, a first detector, a second detector and a control device. The brushless motor is housed in the tool body and configured to drive the tool accessory. The first detector is configured to detect first information corresponding to a load applied to the tool accessory. The second detector is configured to detect second information corresponding to a rotation state of the tool body around the driving axis. The control device is configured to control operation of the drilling tool. The control device is configured to set a conduction angle for the brushless motor based on the first information, and to determine, based on the first information and the second information, whether or not excessive rotation of the tool body due to jamming of the tool accessory occurs.

A power tool is provided including a brushless motor having a stator defining a plurality of phases, a rotor rotatable relative to the stator, and power terminals electrically connected to the phases of the motor. A power unit is provided including power switches. A control unit is interfaced with the power unit to output a drive signal to one or more of the motor switches to drive the phases of the motor over a series of sectors of the rotor rotation. The control unit is configured detect incorrect rotation of the rotor by applying a first series of voltage pulses to a present sector and a second series of voltage pulses to a previous sector, measuring motor currents associated with the first and second series of voltage pulses, and comparing corresponding motor current measurements to detect a transition from the present sector to the previous sector.

A method for fail-safe rotational speed monitoring of a sensorless three-phase drive, in which the three-phase drive is controlled in three phases with the phases U, V, W by drive electronics comprising an inverter, with the voltage signals at the three phases U, V, W being present as pulse width modulated signals, in which an output frequency of the inverter applied to the drive is determined and an actual rotational speed of the drive is determined therefrom, in which the actual rotational speed is compared with a predeterminable desired rotational speed and in which, if the actual rotational speed exceeds the desired rotational speed, the drive is switched off, the pulse width of the pulse width modulated signals being used to determine the output frequency of the inverter.