Gary Coffman wrote:


That's not 220 delta, Harold. That's 240 volt center tapped wild leg delta.
The 240 volt winding between A and C is center tapped, like normal
household 1 ph. The center tap is used as a neutral. The winding between
A and B is a plain 240 winding with no center tap. And the B to C phase is
phantom, ie there is no third phase winding.

This setup is used for small office buildings and light commercial
buildings where the main loads are 1 ph 120 volts or 1 ph 240 volts,
but where there are some 240 volt 3 ph motor loads, usually air
conditioning, pumps, or elevators.

Gary

Gary,

I've never seen or heard of a 240V ungrounded bank. I'm not saying they
don't have them, just never heard of them after 32 years doing linework.
There is however, 240V 3 wire service. 3 hot legs, no neutral. I happen
to have one. There is a delta bank of 1-25KVA and 2-10KVA transformers
that feeds just my property. 240V 3 wire single phase to the house,
which all comes off the 25KVA transformer. And 240V 3 wire 3-phase to a
10HP agricultural pump.

Don