In article , Charles A. Sherwood says...

I assume you are refering to me because I proposed the motor
driving alternator design a while back. (but you quoted someone else)

My comments were specific to Nick who proposed an *electrically*
driven alternator to create a three phase supply, instead of
a rotary converter.

I have looked for surplus motors to build a phase converter but
frankly I have not found the oasis where they are available for cheap.
The shipping costs are usually the killer.

One of the reasons I proposed building a motor alternator setup
is exactly what you quote above. I already have the alternator
and a 5HP motor to drive it. So to me it is cheap.

Obviously in your case the 'works well and is cheap'
approach to life says you should use what you have
available. I would do the same thing if I had a prime
mover available, and no other easy way to get an idler
motor.

I started experimenting with a static phase converter because I
found a used one and a couple people here stated it would
be adequate for my needs. So far it seems to be working; but
running a 3ph motor on 2 windings rubs me the wrong way; Especially
when the run current in those two windings is higher than the
full load current spec of the motor.

Be aware that not all of that is 'real' power. Do see
how much it really is consuming, you need to check the
phase angle or have a true rms wattmeter available. It
might not be as much as you think from an ampclamp check.

Someday I will build that motor alternater setup and experiment
with it too. But for now, I got lots of projects ..

I understand that! I think I'm in the same boat as you on
this.

Jim


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