I wrote: > Induction motors can function as generators. You just need to connect > them to an appropriate AC source and drive them above synchronous > speed.
Gene writes: > Yes, there is that exception, they need an excitation current, true, > but in that case they make excellent brakes as they don't like > spinning above synchronous any better than they like running below it. > And with enough dc current you can come pretty close to stopping them > dead in their tracks. Certainly within one revolution. But the > armature is soft, and its not possible to maintain the magnetic field > from its shorted turns armature long enough to extract any output > power from it for more than a few milliseconds. That's not what I mean. Hook an induction motor to utility power and drive it above synchonous speed. It will power *to* the network. When you put DC current through the field of an induction motor to brake it you are also using it as a generator. It's just that all the power gets dissipated in the armature. -- John Hasler [email protected] Elmwood, WI USA
