Inductive angular position detector with internal test facility - has threshold detector to check voltage presence on inductive circuit, with capacitive circuit between primary and secondary

摘要

An inductive position detector contains a detector to indicate if a fault condition is present. This comprises a threshold detector which is coupled to the inductive circuit and operates even when the position detector enters the null condition. A position detector (5) comprises a rotating transformer with a fixed and a moving coil. The fixed winding is excited from a current source (4) while the secondary winding is connected to phase (6) and threshold (9) detectors. A capacitive circuit is connected between the primary and secondary windings to provide a low level signal on the secondary. This allows the secondary winding to be checked by the threshold detector which indicates when an output is below a reference level. The phase detector (6) provides a dc signal representing position.