Patent ID: 8437923

Claim:
A rotation drive control unit configured to control driving of a rotation mechanism of a construction machine driven to rotate by an electric motor, the rotation drive control unit comprising: a speed command output part configured to output a speed command controlling a rotation speed of the electric motor based on an amount of operation input via an operation part of the construction machine; a torque direction detection part configured to detect a direction of a torque applied on a rotation shaft of the rotation mechanism; and a drive control part configured to generate a drive command driving the electric motor based on the speed command output from the speed command output part and to control driving of the electric motor, wherein in starting a rotation of the rotation mechanism, the drive control part starts driving the electric motor using the drive command if a direction of the rotation represented by the speed command output from the speed command output part and the direction of the torque detected by the torque direction detection part are opposite directions.