On my 16 speed import drill press (of which only about 3 sperds are useful)
w/ a capacitor/centrifugal starting circuit (that clicks out at speed), I
discovered that if you disconnect the starting circuit, the motor stalls,
but will spin in either direction you set it in by hand, and then continue
in that direction when the motor circuit connected.
Yeah, a little rustic....

I figger this could be wired in properly, as single phase lathe motors w/
centrifugal switches are reversible.
And in those, if you attempt to reverse the motor before the centrifugal
switch drops out, it will continue in the same direction even tho the handle
was thrown in the reverse direction!
I screwed up more than a few tapped holes that way.

Often the techs at the motor mfr can be helpful w/ this.
As can small motor winding shops. Bring it to them disassembled, I'll bet
they can point to the "right wires" in about 2 seconds--no charge. Proly
just need a dpdt switch from radio shack (two 3-way wall switches will work
in a pinch).
--
Mr. P.V.'d
formerly Droll Troll
"Bernard Arnest" wrote in message
oups.com...
Hi,
I'm looking around motor for a grinder. someone pointed out that
compressor-duty motors are non-reversible. I didn't think this an
issue previously, but it occurs to me that if I build a buffing wheel
opposite the grinder, off the same motor, for each to run in the proper
rotation I would have to reverse the rotation of the motors.

Assuming a conventional, reversible motor (I'm not on the question
of compressor motor or not here), does this involve rewiring the motor
each time? Even if just 10 minutes of work, it would be a nuisance;
since it would not just be a one-time rewiring, but every time I want
to switch between machines. Could I build a simple device that would
rewire it by flipping a switch, if this is the case?


btw, how much more efficient is 3 phase over 2? It seems a
converter is affordable off of ebay, and it looks like it would make
every subsequent motor cheaper, and/or more efficient and
smoother-running?

thanks!
-Bernard Arnest