I'll second this advice!!!

A three phase motor with one phase tripped out or dead is
going to burn out very soon.

It's called "single-phasing".....

John


On Thu, 5 Feb 2004 21:19:48 -0600, "Hugh Prescott"
wrote:

Bad idea to use 3 single phase breakers for 3 phase power as you can have
one trip out and still leave two of the motors phases powered, will let the
smoke out of the motor and possibly you..

Or you can trip two of the breakers and still have voltage on the motor,
this can let the smoke out of you if troubleshooting.

Code requires all three phases to trip if any phase overloads. Same logic
applies to 220 1 phase devices both hot leads must disconnect.

Hugh





om...
Also, I thought of after I posted the above, regular circuit breakers
(the type in your home distribution panel) are really cheap (Home
Depot, Lowes, etc...)and not only provide switch function but also
protection. If you want a 3-phase breaker, simply gang three
together.

Sid


That is the way to go. I am somewhat intimidated by what I see and am
not sure what some of the switches do. But you are absolutely correct.
All of it can be controlled with the drum switch to reverse the motor
and the pump by pulling from a leg of the power circuit. Heck, I am not
above running a separate cord to the wall for the coolant pump. Thanks
for making me focus.

sidk wrote:

Bruce,
If it were mine I would forget about trying to fix the old wiring. I
would rip it all out and start new using SSRs (Solid State Relays)
which are relatively cheap.
So, what is to operate?
1) the rotary converter.
2) switching on the 3-phase lathe motor after the converter is
running.
3) Lights
4) Cutting-oil/coolant pump
5) ? whatever else....?

The transformer is probably simply to provide 115V for the pump,
light, and relay coils. You will already have 115V available as half
of your 230.
Compared to aircraft wiring, this is rather basic.

An additional thought... Why the burned up relay??
It could be that the 3-phase motor is NFG. Or a short in the wiring
somewhere.
It might be worth your time and effort to just "haywire" only the
converter and motor together (isolated from any "original" wiring) on
a temporary basis to determine if the thing will run. If it does, then
build up from there.

Sid Knox
Velocity N199RS
Starduster N666SK
KR2 N24TC
W7QJQ

"Bruce A. Frank" wrote in message
...
I have come by a lathe that has some electrical problems. The unit
has a
2 hp 3 phase 220 volt motor. One of the magnetic relays was burned
out
when I got the lathe. I replaces the relay, turned the switch on and
the
brand new relay burned up also.
.
.
.