Absolute position measuring resolver apparatus with backup means in power failure.

摘要

A resolver apparatus for measuring an absolute position of a rotating body comprises a resolver (1) including a rotor having a single-phase exciting coil (11) and adapted to be coupled with the rotating body (20) and a stator having detection coils (12a, 12b) for two phases different from each other by 90 DEG , a first circuit (2) for exciting the exciting coil by a pulse signal having a selected frequency, and a second circuit for calculating an absolute position of the rotor measured from a reference angular position on the basis of output signals of the detection coils, wherein a selected area including the first circuit and at least a part of the second circuit is normally energized by an external power supply (22) and when the external power supply is disabled, is energized by a backup power supply (8). <IMAGE>