RadioBanter - View Single Post - why 3-phase power?

January 2nd 04, 08:49 PM

wrote:

In sci.electronics.basics Rob Paisley wrote:

| For larger horsepower motors, Three Phases means that they will
| start with no external mechanical assistance.

And, as I understand it, they can then "stand on one leg" although they
will be a bit "shaky".

You can also reverse the rotation by swapping two of the phases. If one
phase is blown you can start it by giving it a spin in the right
direction, 'without' getting your hand caught. I had to replace one at
work once on a rooftop air conditioner, even though I was an electronics
engineer I was the only one who volunteered. It was only about 130 on
the black tar roof. I came down a hero to the assemblers who were under
it but had to leave and take a shower after that one, seems no one would
get near me for some reason. One leg may be possible if there is a
center return wire but I didn't try it.
Bill Baka