Pete Keillor wrote:
On Wed, 26 Jan 2011 13:06:20 -0600, "Pete
wrote:

(...)

One additional note is that there aren't too many three phase loads
you'll run across that will be harmed by running reverse rotation for a
couple seconds, so most of the time you can just blip the load on and
see if it's running the correct direction, and if it isn't swap two
phases before trying again.

Don't try that if there's an impeller threaded on a shaft. If
possible, I had motors decoupled from loads before doing that. Wasn't
always possible.

I got away with it. (I realize that does not necessarily
mean that the decision was wise or safe).

In my defense, inspection of the impeller showed that the
pump in question was little more than scrap anyway.
It was missing most of a vane and the rest of it was *very
badly* corroded and pitted.

The impeller didn't unthread and the 'magic smoke' stayed
in the motor. Call me lucky.

--Winston