A method of operating a power tool having a motor and a controller is provided. The method includes: setting a protection time limit associated with a condition of the motor; taking protective action to shut down the motor if the condition of the motor persists for a duration of the protection time limit; and in response to occurrence of the condition during a start-up period of operation of the motor, extending the protection time limit for a duration of a constant-clutch time period to allow an output speed of the motor to reach or exceed a speed threshold, and taking protective action to shut down the motor if the output speed of the motor remains below the speed threshold for the duration of the constant-clutch time period.

A method of operating a power tool having a motor and a controller is provided. The method includes: setting a protection time limit associated with a condition of the motor; taking protective action to shut down the motor if the condition of the motor persists for a duration of the protection time limit; and in response to occurrence of the condition during a start-up period of operation of the motor, extending the protection time limit for a duration of a constant-clutch time period to allow an output speed of the motor to reach or exceed a speed threshold, and taking protective action to shut down the motor if the output speed of the motor remains below the speed threshold for the duration of the constant-clutch time period.

A resonant motor system having a resonant circuit that includes magnetic coils and of capacitors, for generating an electric power when the resonant lot is rotated by an engine, a regenerating portion for the resonant motor, a motor driving portion, a motor control portion, and a capacitor portion for storing therein the electric power generated by the resonant motor when the resonant motor is regenerated, the resonant rotor being driven by the electric power stored in the capacitor portion when the engine is assisted by the resonant motor.

Provided is an electric brake device that can achieve improved control accuracy without involving a cost increase. The electric brake device includes an electric motor, a brake rotor, a friction pad, a transmission mechanism, a braking force command section, a braking force estimation section, a motor rotation angle detector, and a controller. The motor rotation angle detector, which is used in a partial region of a braking force from a minimum braking force to a maximum braking force, has a higher resolution than a motor rotation angle that causes a braking force fluctuation equivalent to a minimum braking force resolution of the braking force estimation section. The controller includes a resolution interpolation section configured to interpolate, by using a motor rotation angle detected by the motor rotation angle detector, a minimum resolution of the braking force obtained by the braking force estimation section.

A method of operating a power tool having a motor and a controller is provided. The method includes: setting a protection parameter associated with an anti-kickback protection of the power tool; and taking protective action to shut down the motor if a condition of the motor meets a criterion associated with the protection parameter. The protection parameter is set to a first value during a start-up mode of operation to allow an output speed of the motor to ramp up until the output speed of the motor reaches or exceeds a speed threshold, and the protection parameter is set to a second value different from the first value during a normal mode of operation after the output speed of the motor reaches or exceeds the speed threshold.

A method of operating a power tool having a motor and a controller is provided. The method includes: setting a protection parameter associated with an anti-kickback protection of the power tool; and taking protective action to shut down the motor if a condition of the motor meets a criterion associated with the protection parameter. The protection parameter is set to a first value during a start-up mode of operation to allow an output speed of the motor to ramp up until the output speed of the motor reaches or exceeds a speed threshold, and the protection parameter is set to a second value different from the first value during a normal mode of operation after the output speed of the motor reaches or exceeds the speed threshold.

A linear eddy current brake includes a brake plate and a moving rotor with magnets having magnet surfaces which generate inductions in the brake plate and induce eddy currents about the magnet surfaces. The brake plate is divided by slots in the brake plate into open segments insulated from one another which reduce the brake force of the eddy current brake (WBS). The open segments are electrically connected or short-circuited to increase the braking force of the WBS. The eddy currents of the segmented brake plate (S-brake plate) flow in the respective open segments and in a conductor region which connects the open segments on one face. The S-brake plate is functionally divided into a securing region, contact region, induction region, and a conductor region, and the regions of the S-brake plate, except the conductor region, are divided into segments which can be short-circuited by slots running in the transversal direction.

A linear eddy current brake includes a brake plate and a moving rotor with magnets having magnet surfaces which generate inductions in the brake plate and induce eddy currents about the magnet surfaces. The brake plate is divided by slots in the brake plate into open segments insulated from one another which reduce the brake force of the eddy current brake (WBS). The open segments are electrically connected or short-circuited to increase the braking force of the WBS. The eddy currents of the segmented brake plate (S-brake plate) flow in the respective open segments and in a conductor region which connects the open segments on one face. The S-brake plate is functionally divided into a securing region, contact region, induction region, and a conductor region, and the regions of the S-brake plate, except the conductor region, are divided into segments which can be short-circuited by slots running in the transversal direction.

A magnetic gear embedded rotating electric machine control device, which controls voltage applied to a stator winding of a rotating electric machine having a magnetic gear therein so that an output from the rotating electric machine follows an output command, includes: a damping command generator which generates a damping command using an angle between a stator and a high-speed rotor of the rotating electric machine detected by an angle detector; a first adder which adds the damping command to the output command, to generate a corrected output command; and an output controller which controls an output generated by the rotating electric machine, in accordance with the corrected output command.

A magnetic gear embedded rotating electric machine control device, which controls voltage applied to a stator winding of a rotating electric machine having a magnetic gear therein so that an output from the rotating electric machine follows an output command, includes: a damping command generator which generates a damping command using an angle between a stator and a high-speed rotor of the rotating electric machine detected by an angle detector; a first adder which adds the damping command to the output command, to generate a corrected output command; and an output controller which controls an output generated by the rotating electric machine, in accordance with the corrected output command.