Magnetic pole changer for AC or three phase generators - uses permanent magnets arranged to control contacts of dry reed relay bridge circuits

摘要

The pole changer is designed for use with A.C. or three-phase generators and has electronic circuitry for rectification (diode-bridge circuit). The pole changer provides a polarity at the output terminals dependent on the direction of rotation of the generator's armature. This arrangement is for tachometric measurement of speed of revolution (revs.) in measurement generators etc. A bridge circuit contains a pole pair which holds open or closed, two contacts, by a magnetic field effect from several permanent magnets which operate dry reed relay bridge circuits. This provides a D.C. voltage of varying polarity according to the rotation of the machine armature, even at idling speeds down to almost standstill conditions, and without interference from shaking or vibration.