On Thursday, January 14, 2016 at 11:46:03 PM UTC-5, Martin Eastburn wrote:
I had students with a Can manufacturing company that got a big
machine that was 3-phase all over it. the motors had to start
in the correct direction the first time. I seem to recall something
like gear train destruction would occur. I luckly found a Neon lamp
tester in a magazine that fit the bill. This was in the early 70's.

Martin

On 1/12/2016 12:09 PM, Leon Fisk wrote:
On Tue, 12 Jan 2016 09:57:33 -0800 (PST)
rangerssuck wrote:

snip
How do "real" electricians identify the phase connections when they can't count on the wire colors?

I was only an "apprentice" but 30 years ago we just hooked up the
equipment and noted the direction. Once we had a really expensive
plastic injection machine. That was a bit nerve wracking. We had one
of us watch a motor and the other give it a quick bump on/off. We had it
wrong of course, switched the wires around, it worked okay yet...

Nowadays you can buy rotation testers for not so much. I would just buy
one if I was still working with that kind of stuff. For instance:

http://www.amazon.com/s/ref=nb_sb_no...3+phase+tester


This http://www.byramlabs.com/store/produ...ion%20Te ster is the real deal, but Greenlee had the 5774 and probably has a replacement that can do the job as well. You can connect the motor and turn it by hand and it will tell you what phase you need to get the motor to turn that way. Then you connect it to the line and it will tell you what phase you have.

Being that those things aren't at all cheap, I went with one of the $20 units from amazon that just displays the phase of the power line. I'll test all the outlets in question and change the fewest possible to get them all the same. This will probably be early next week.