Name: Moe A.
Date: May 2004
Are there any advantages of this design over a squirrel-
cage to justify the higher cost, or was this a predecessor
of the squirrel-cage design?
It is pretty clearly a gimmick to add startup torque to an induction motor.
Purely symmetric AC induction-motors have zero torque when at zero velocity.
Shaded-pole motors have this symmetry broken a bit, but the startup torque is still too weak if there is a viscous or heavy load on the rotor.
Capacitor-start motors sound like the nearly equivalent thing today.
I cannot compare advantages in detail, but I tend to think your motor's characteristics are somewhere between
capacitor-start and shaded-pole. I do not know the history.
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Update: June 2012