Hi again Mike!;

I'll be glad to give some basic answers to this Q.

First off, these types of Motors have one thing in common - they are all AC Induction Motors.
They function similar to the operation of a Transformer - as each has a Primary and Secondary winding (or windings).
For the Induction Motors, the Primary winding(s) are referred to as the Stator, and the Secondary winding(s) as the Rotor.

The two windings are physically separtated by an air gap.

Input KVA to the Stator is induced into the Rotor, which rotates and transduces Torque + Horsepower as required.
The "Windings" on the Rotor (Secondary) are embedded as bars (or other types of configurations) - and the entire assemblidge resembles a "Squirrel's Cage" (like an excersize treadmill).

As to the types, here's a basic description of each:

* Induction Motor (Cage motor):
The basic and common type used. Referred to as "Squirrel Cage Induction Motors" - they are the single or two-speed steady RPM type Motors (normal case) - with the "dual voltage options".
Squirrel Cage Motors range from the 1Ø Split Phase types (Resistance start, Capacitor start, PSC and Shaded Pole) through the Delta and Wye connected 3Ø types. These Motors slip behind the syncronous frequency when developing torque.

* Synchro Motor:
These are Induction Motors which run at the syncrronous speed of the AC frequency.
For a 2 Pole Motor at 60 Hz, this speed is 3600 RPMs.
These Motors are part Squirrel Cage and part DC windings. The DC windings are wound to the Rotor.

* Slip-Ring Motor:
These are Wound Rotor type Induction Motors.
Instead of having the Secondaries short circuited, they are connected together via external Resistances to achieve speed control.
They also slip behind syncronous frequency when developing torque.

Hope this is helpful!

If further information is needed, let me know!

Scott35


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!