Position detecting apparatus having electric motor and method for detecting position

A reference position detecting apparatus comprising:

• an electric motor that includes a coil device and a rotor, the rotor rotating when the coil device is supplied with electricity;
• a driven object that is driven by the rotating rotor;
• a tapping control unit that performs a tapping control, in which the rotor rotates to a limit position on one side in a movable range of the driven object;
• and
• a reference position recognizing unit that defines a point, at which rotation of the rotor stops, as a reference position of one of the rotor and the driven object during the tapping control,
• wherein the coil device has a first coil group and a second coil group,
• the first coil group includes a plurality of first coils, which electrically connect with each other,
• the second coil group includes a plurality of second coils, which electrically connect with each other,
• the first coil group including the plurality of first coils is electrically separated from the second coil group including the plurality of second coils, and
• the tapping control unit controls electricity supplied to either one of the first coil group and the second coil group to rotate the rotor during the tapping control.