For all practical purposes a 7.5 HP RPC running a 2 HP machine should not
require much in the way of balancing. I suggest as a first test:

1. Run the RPC with the lathe turned off. Does it overheat?

2. Run the lathe unloaded (no cutting). Does it overheat?

If the answer to either is "yes", then the respective motor is probably
defective.

Bob Swinney
wrote in message
ups.com...
I use a 7.5HP rotary phase converter to run my 2HP Sheldon Lathe. I was
taking a medium cut in some 1020 steel in backgear and after a couple
of passes it seemed that the lathe was losing power. I opened the
cabinet up and the motor was very hot. If I disengaged the power feed
and retracted the tool the lathe would come back up to speed.

The motor is the original and it is wired properly at 220v.

Is it possible that the converter not being balanced or tuned is
causing this power loss. Bob Swinney sent me an article on balancing so
it will not be a problem to do so as I have ordered some run
capacitors.

I do not have the voltages right now on the 3 legs. Should I measure
these with the lathe running with no load?

Thanks, Steve