Don Young sez:

"Since the running idler and load motors are directly connected in parallel
.. . ."

You are right about there being "many ways to understand and describe how
things work" but the concept of an idler and load motor's respective
windings being in parallel is not one of them.

Bob Swinney

"Don Young" wrote in message
...
wouldn't plug reversing with identical motors and no mechanical load have
an equal chance of reversing either motor? When running free, it seems to
me that either motor could be considered to be the source or load for the
third phase leg. I tend to believe that the idler requires more mechanical
inertia than the load to maintain the best functioning.

If an induction motor does not "generate", is induced counter EMF
imaginary and the use of common induction motors as generators impossible?
There are many ways to understand and describe how things work and I like
to think of the RPC as simply a running induction motor with the
magnetized rotor inducing EMF not only into the line energized windings
(counter EMF) but also into the unenergized and phase displaced windings.
Note that, when disconnected and still turning, an induction motor still
has voltage across its windings and loading this voltage with "braking"
resistors will mechanically load the rotor. I do not claim that this is
the only way to describe it or that any description can change the
operating principles involved.

Don Young
"Christopher Tidy" wrote in message
...
Hi all,

I'm trying to figure out if there is any benefit in adding a flywheel to
a rotary phase convertor. I've heard varying opinions on the subject.
Having thought about it myself, I've reached the following conclusions:

(i) The sag in voltage on the third line is caused by the fact that it is
not connected directly to the supply. The flywheel doesn't change this.
Nor will it change the steady speed at which the rotor turns, so unless
it has some averaging effect on a cycle-by-cycle basis which I haven't
considered, it won't affect the quality of the three phase output when
the convertor is running in a steady state.

(ii) It might be an advantage when trying to plug reverse the load motor.
As far as I can see (on the most simplistic level), the motor with the
most kinetic energy will win.

I can't seem to find any used flywheels to fit my motor, but I can get a
brand new flywheel for £40. I'm not sure if it is worth it in order to
satisfy my scientific curiousity. If I get a different motor, I can get a
flywheel for next to nothing, but that will involve lots of effort,
bartering and deals in order to get a motor which isn't quite so cool.

Any opinions and arguments? Thoughts would be appreciated...

Best wishes,

Chris