hysteresis motor 1

[electricpete]

Has anyone heard of a "syncronous hysteresis motor".

Supposedly it will "develop smooth constant starting and accelerating torque" and "synchrozine any load with thier torque rating regardless of inertia".

I'm curious what how it works. I know that it has only 115vac single phase power applied. It has no separate field circuit like a large syncronous motor.
(this one is a fractional horsepower motor).


More importantly, are there any special considerations for rewind of a motor like this?

 

[jbartos]

Suggestion: Reference:
1. Gordon R. Slemon "Magnetoelectric Devices, Transducers, Transformers, and Machines, John Wiley and Sons, 1966,
Section 5.5.8 Hysteresis Machines, page 437
Eng-Tips:
"The hysteresis motor is a permanent-magnet machine designed such that the stator magnetomotive force can produce and change the state of magnetization of the rotor material. The rotor may consist of a solid cylinder of permanent magnet material.
The motor advantage is its ability to accelerate high-inertia loads up to synchronous speed."

 

[electricpete]

Let me clarify my question on rewinds:

Are the differences between hysteresis syncrounous motor and squirrel induction cage motor confined to the rotor? Or is there a difference in the stator?

 

[jbartos]

Comment: The stator is of normal cylindrical slotted construction and carries polyphase distributed windings. The rotor is somewhat magnetically dynamic, changes magnetic material flux density Bo and magnetomotive force Fo.
Fo=(Ns x Is x ms x cos(ws x t + alfas - theta) in amperes
where
Ns are stator winding turns
Is is stator current
ms stands for stator number of phases
ws is angular synchronous speed in rad/sec
alfas is the stator current fasor angle
theta is positive angle of rotation at speed ws
The torque of the rotor acts in direction of positive theta, tending to align the magnetic axis of the distributed rotor flux density with the magnetomotive force axis of the stator.