APPARATUS FOR SENSING DIRECTION OF ROTATION

摘要

The direction of rotation of a shaft (11) is sensed by means of a rotor (10) which carries magnets (12) which present alternate north and south poles to angularly aligned detectors (13a, 14a). Detector (13a) provides a voltage signal only in the presence of a north magnetic pole and detector (14a) provides a voltage signal whose polarity is dependent on the polarity and direction of rotation of an adjacent pole of a magnet (12). The detector output signals are compared in a logic circuit and provide an instantaneous signal indicating direction of rotation. Additional detectors (13b, 13c, 14b-e) provide similar output signals and are positioned to obviate uncertainties arising from dimensional tolerances in the main detectors (13a, 14a).