I recently bought a 1.5HP 3ph Baldor 10 inch grinder with 1/2HP 3Ph
dust collector.

I connected them to a Phase-a-matic static phase converter; They
start and run ok, but they do seem to draw a bit more current
running on single phase than 3phase.

I figured that the big grinder would act like a rotary phase
converter for the dust collector, but I don't see any current
in the third leg with a clamp on ampmeter.

Input is L1 and L2. I measure
L1:L3 208V
L2:L3 224V

Should I experiement with some run caps or just leave it alone?

Another interesting fact is that the baldor grinder is rated
1.5 HP but FL current is 2.5 amps. I have 1.5HP on my rockwell
mill and that motor is rated 4.6 amps. Is baldor guiltly
of over rating like sears?

chuck