Despite living deep in cattle country, three phase power wasn't
available to me when I moved into my new shop.
This was a pretty tough break, since my mill had a three phase motor
on it. Rutland (the old-local machine supply shop I kept in touch
with) had three-phase converters for a decent price so I picked one
up. The mill had a one HP motor on it, but I figured I might be
expanding in the future, so I went for the "1-3 HP" solid state
phase converter they offered.
First word of warning: they put a lower limit on that range on
purpose. The box apparently counts on the motor turning at least one
pole on the initial jolt to get some sort of phase-locked cycle going.
The mill tends to stall about half the times I try to start it and I
have to try again. The instructions warned of this problem.
But my plans for the future paid off well. I got tired to trying to
do any meaningful work on the little 11"x30" Logan lathe I have (for
sale, by the way. Send mail for details.) I picked up a Harrison
14"x40" lathe, which incidentally had a dual-speed three-phase motor.
The higher speed was three HP. Good decision, history-wise.
I spent a few hours on Sunday rewiring that corner of the shop so the
mill and lathe could share the phase converter. I tried the mill
first, just to make sure I didn't fuck anything up, and it seemed to
work as it had. I then tried the lathe. The switch did nothing. I
tried a different speed. Nothing. Diddle the plug. Nothing.
The Fluke showed power in the attached fuse box, so I continued
tracing. Power in the seemingly extraneous breaker box, as well. I
opened one junction box to find what looked like a lump of dried mud.
I poked, but it held solidly. I picked and dug and found a nest of
larval *somethings* that I scraped out and disposed of, but still no
fire.
Then I realized one leg of the three phases was dead. Makes sense.
So I started the mill. With the mill started, the lathe worked
perfectly, with all three phases "active." Swapping a pair of wires
was enough to get the the on/off switch solenoid working, and all is
fine.
So, after a little story-telling, I'm interested to know if anyone
else has any expereince with phase converters, mechanical or
solid-state, and any stories, comments, or recommendations.
andy
banta@abingdon.sun.com
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