Patent ID: 7071640

Claim:
A rotation drive control device of a three-phase DC motor comprising: a drive control unit; and a three-phase DC motor including three-phase coils and a rotor, wherein the drive control unit generates a first current that flows through each of any two phases of the three-phase coils to detect a polarity of an induced voltage induced in a de-energized phase of the three-phase coils so as to determine a direction of energization and corresponding two phase coils through which a second current flows to rotate the rotor, wherein the drive control unit controls a start-up of the three-phase DC motor based upon a first determination in connection with the direction of energization and the corresponding two phase coils, wherein the rotor does not respond to the first current, wherein when the drive control unit determines that any two detected levels of the induced voltages are larger than a predetermined level, the drive control unit determines the direction of energization and the corresponding two phase coils by using two detected polarities of the induced voltages in connection with said any two detected levels, so as to rotate the rotor based upon the direction of energization and the corresponding two phase coils thereof are determined, and wherein when the drive control unit determinates that said any two detected levels in connection with the induced voltages are larger than the predetermined level, the drive control unit determines the direction of the energization and the corresponding two phase coils by ignoring a detection result of a polarity of an induced voltage of the de-energized phase of the three-phase coils whose induced voltage is smaller than the predetermined level.