Inductive frequency generator for measuring magnetic tape drive - has magnetic circuit with 2 radial arm gaps between coil former and toothed outer shunt

摘要

The frequency generator for measuring the rotary motion of a tape, or disc drive has a ferromagnetic coilformer (1) with a magnetic coil (2), the side flanges (3, 4) of the coilformer having a differing dia. and cooperating with a ferromagnetic toothed rim (7) to form a magnetic circuit with 2 air gaps (11, 12). The larger dia. coilformer flange (3) is similarly toothed for engaging the toothed rim, the toothed air gap (11) exhibiting a greater radial spacing than the other air gap (12) and varying in dependence on the relative position of the teeth (5, 10). ADVANTAGE - Precise rotation measuring with reduced complexity.