Electric power tool and motor control method thereof

1. An electric power tool comprising:

a motor;

a hydraulic pressure generator driven by the motor and configured to generate a plurality of impacts in one revolution thereof;

an impact angle detector configured to detect an impact angle in one impact of the hydraulic pressure generator;

an electric current detector configured to detect an electric current applied to the motor;

a determination unit configured to determine an impact failure based on the impact angle and the electric current detected by the impact angle detector and the electric current detector; and

a rotation controller configured to decrease a rotation speed of the motor when the determination unit determines the impact failure.

2. A motor control method of an electric power tool in which a hydraulic pressure generator driven by a motor generates a plurality of impacts in one revolution thereof, the method comprising:

detecting an impact angle in one impact of the hydraulic pressure generator with an impact angle detector;

detecting an electric current applied to the motor with an electric current detector;

determining an impact failure based on the detected impact angle and the detected electric current with a determination unit; and

decreasing a rotation speed of the motor when the impact failure is determined with a rotation controller.