Slow running AC synchronous motor - has two rows of pole shoes which ensure correct starting torque in required direction of rotation

摘要

A motor containing a cylindrical rotor (18) is made of soft iron having two sets of six teeth (h) arranged at one end, the sets of teeth having an angular spacing of 180 deg., and a stator from which the alternating magnetic flux generated by a single coaxial coil (6) derives, has two sets of pole shoes on the stator, a left row (a nd b) mounted on the base ring (14) and a right row (c and d). The last mentioned pole pieces have metallic shading rings (15) and shading discs (16) causing phase shift of the magnetic flux. The pole shoes of the left and right row are staggered against each other over a substantial angular distance in order thereby to ensure a good starting torque in the desired rotary direction.