Induction type vibration transducer - has permanent magnet balanced in tube and axially displaceable by vibrations between pair of sensor coils

摘要

The transducer includes a hollow cylindrical housing containing a coaxial sleeve, pref. of teflon. The ends of the sleeve are closed by two permanent magnets which are pole-orientated in the same sense with a cylindrical permanent magnet. The magnet is movable in the space between the two end magnets. The movable magnet has a chrome-coated brass outer layer or other low friction coating and is orientated in the opposite sense to the end magnets so that it is retained centrally by magnetic repulsion forces. Vibration axially moves the magnet between two bifilar windings axially spaced on the sleeve each side of its centre, the bifilar windings generating no magnetic field.