Harold and Susan Vordos wrote:

"William" wrote in message
news:fQire.47092$_o.36229@attbi_s71...

"Pete C." wrote in message
...

My 3 phase delta 240/120 volt service was installed just 4 years ago,

at

my

request. I did not want a wye service (for obvious reasons), and am
transforming to 480V for one machine.

Huh? What "obvious reasons"? 120/208 Wye service has no disadvantages
that I know of. You can get 120v from any of the phases, allowing you to
balance your single phase loads and single pole, two pole or three pole
breakers breakers can occupy any panel position since all phases are
equal to each other and to the neutral.

Well there are disadvantages from the 208 voltage, a lot of motors will

not

run at 208 with out overheating them. And my band was blade welder didn't
really like it either, had problems welding the larger blades. The oven
elements also don't seem to get as hot, cloths dryer, etc.....

William...




Exactly! I'm still at a loss to understand why the delta system is
such a problem.
Seems to me the Wye system, *for a machine shop*, would be far more
disadvantageous. You'd have to be completely out of your mind to request
it if delta was available.

Harold



You're right, Harold. I think the 3 transformer delta service is the
better of the two. One advantage is that when one transformer goes out a
trouble shooter from the power company (me) can go out and rebuss it
into an open delta and have you back up and running in 30 minutes. The
two transformer open delta is only good for 86.6% of the KVA rating of
the two transformers. So you might have to shed some load.

Don