Em 8/6/2012 13:43, RussellMc escreveu:
>> If the rotor is short-circuited, then we have a 3-phase induction motor.=
...
> I haven't examined an auto alternator with that in mind BUT a squirrel
> cage motors is a very very specialised beast indeed, optimised to
> achieve the rather interesting dual task of exciting the rotor and
> applying a rotating motive field to drive it. The rotor excitation is
> achieved by the slip frequency field whereas a brushed DC slipring fed
> field is  mechanically vastly vastly* different. May be able to be
> made to rotate but I'd doubt it would be able to be made to make much
> power at all**.
>
>
>        Russell
>
> * [TM]
>
> ** But, as ever, I may be wrong.  Just ask Bob B :-).


And if the rotor is short-circuited through a rheostat (well, not
exactly a short circuit) then we get a "torque motor" (a motor that
maintains a nearly constant torque, even stalled).


Isaac


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