Patent ID: 8111032

Claim:
An indicating instrument for a vehicle comprising: a step motor that includes a field winding and is rotated upon application of a drive signal to the field winding, wherein the drive signal is an alternating current that alternates in accordance with an electrical angle; a pointer that is rotatable in synchronization with the step motor, wherein: the pointer points to a vehicle state value, which is indicated with a zero value as a reference thereof, in accordance with a rotational position of the pointer; and the pointer is rotatable in a zero-reset direction to return to a zero position that indicates the zero value; a stopper device for stopping the pointer, which is rotating in the zero-reset direction, at a stopper position that is located within a predetermined range from the zero position in the zero-reset direction; a detecting device for detecting an induced voltage generated in the field winding at each of a plurality of detecting points, which are electrical angles at intervals of 90 degrees and include a zero point that corresponds to the stopper position; and a control device for performing zero-reset control, whereby the control device controls the drive signal so as to rotate the pointer in the zero-reset direction, wherein in a state of abnormal detection in which: the detecting device detects the induced voltage that is larger than a predetermined set value at the zero point; and the detecting device detects the induced voltage that is equal to or smaller than the set value at a next detecting point to the zero point, the control device assumes loss of synchronization of the step motor and continues the zero-reset control until an assumptive electrical angle that corresponds to a rotational position of the pointer reaches the zero point.