Slow-rotating AC synchronous motor - uses phase-shifted rotating fields to induce axial currents, with magnetic flux passing through rotor drum disc and back to stator yoke

摘要

In the synchronous sections of the stator phase shifted rotating fields are produced which pass through the drum -shaped metal rotor. These fields induce currents in an axial direction and in turn give to a turning force in the drum. The pole pitch of the synchronous section is adapted to the pole pitch of the a synchronous section and has the effect that the rotor for each half wave of the applied alternating voltage turns by a well defined angle. The magnetic flux of the synchronous section passes through the rotor drum disk and back to the stator main yoke. Where the starting momentum is insufficient the drum may be made axially movable against the force of a spring; in that case the magnetic forces themselves after assisting the starting torque would draw the drum axially into its optimum operating position.