Stepping motor apparatus comprising electrical detent means

Abstract

The phases of a multi-phase stepping motor (16) are individually energized to rotate the motor shaft (14) to a desired step position. A sensor (12), (27) driven by the shaft (14) is constructed to generate a plurality of position signals (L1), (L2), (L3) equal in number to the motor phases. The position signals (L1), (L2), (L3) are symmetrical and are displaced in phase from each other by the angle (15.degree.) between adjacent shaft steps. These signals (L1), (L2), (L3) are decoded to energize the motor phases in such a manner as to rotate the shaft (14) to a next step during rotation of the shaft (14). A hold decoder (26) decodes the position signals (L1), (12), (13) to energize the motor phases in such a manner as to hold the shaft (14) at the desired step when rotation of the shaft (14) is stopped. If the shaft (14) is manually rotated to another shaft position, the hold decoder (26) will energize the motor phases in a different manner so as to hold the shaft (14) at the new step. In this manner, the motor shaft (14) may be manually rotated to and electrically held at any step.

Dependencies are inferred from the claim text.