On Tue, 12 Jan 2016 11:49:20 -0800 (PST), rangerssuck
wrote:

On Tuesday, January 12, 2016 at 1:25:23 PM UTC-5, wrote:
On Tue, 12 Jan 2016 09:57:33 -0800 (PST), rangerssuck
wrote:

I'm doing some work in an older factory - MANY electricians have had their hands in this place.
They called me today with a problem:

They have a piece of equipment they have been moving from room to room. It has a 3-phase
230V motor (about 1 HP). In some rooms it runs backwards, so they have been swapping wires inside the motor junction box.

They asked me whether I could add a reversing switch, with a lockout to prevent it from switching
while it's running. Well, yes I could do that, but why don't they just rewire the outlets so they're all the same?

Well they think that's a great idea. And I should go up there and make sure they do it right.

So, I COULD identify the correct wiring by simply by plugging in the motor and checking for correct rotation,
but surely there's a better way? What if this was a big piece of equipment, or something that would do damage
if the motor turned the wrong way?

I COULD hook up my oscilloscope (and it always impresses the hell out of them when I pull that out),
but is there an even better way? How do "real" electricians identify the phase connections when they can't count on the wire colors?

[just to get back on the off topic]
How would Bernie, Hillary and Donald do it? How would they do it in Oregon?

Bernie would demand a fixed minimum income for electricians so that
they'd have more free time to bone up on the latest developments in 3
phase wiring.

Hillary would ask her donors for enough money to fund 6 national polls
to see what she should do.

The Donald would blame the problem on China and Mexico and say that he
knows the secret and if he was in charge all wiring colors would be
very very very correct and the most uniform in the history of
electricity. If pressed sufficiently he would produce a rummy former
electrician who would recommend a three black wire national standard.

We here at the Oregon occupation think you should wait until dark, cut
the locks at a better location and move in there.

O.R.E.O.s

PS Why do you need a switch anyway? Save the money and join the
revolution. Sooner or later we'll take over a VFD distributor. Then
all you'd have to do is read a manual and press some buttons to change
direction.

If we could just take over the national power grid, I could use an app on my phone to change
the rotation on every three-phase motor in the country. That would be very cool.

I'd come to Oregon to join the mob^H^H^Hrevolution, but I'm busy standing guard here
in New Jersey. If Christie gets any closer to be taken seriously, we plan to blockade all
of the ball fields where his kids play so he won't be able to land his helicopter. Can you run
a campaign from a helicopter that can't land? Surely there are papers that must be signed.

Hopefully Trump will win the nomination. Which would free up Christie
to join the revolution. Lots of room for his chopper here. I bet he
knows how to block the bridge to Oregon.

O.R.E.O.s

PS Plus, if we run out of food at the compound, Christie's thighs
alone would last us a week.