Re: Delta vs. Wye

richard_damian@... wrote:

> My question is the external wiring of the connection to the motors. I
> have
> several GE motors that are obviously wired as a "Y". I have a
> Reliance
> double-speed motor that has nine leads and I successfully wired as a
> "Y"
> also. Is the existance of a neutral wire the difference between
> motors
> wired as "deltas" or "Y's"?

Not necessarity. All motors wired as Wye have a center tap. In MANY
cases,
dual voltage motors do NOT bring out the center point, however. These
motors
often have a standard wire numbering scheme, where the wires labeled 7,
8 and
9 are one end of a winding, and the other end of these windings are tied
together
deep inside the windings, and not brought out to any terminal you can
access.

The actual difference is whether the windings are wired from line to
line or
from line to the neutral point, whether than neutral point is accessible
or
not. With proper 3-phase excitation, the two motor winding schemes are
equivalent, and it is actually hard to tell one from the other. With
improper
excitation or single phase operation, these is a slight difference. It
is also
pretty much impossible to figure out which wiring you have from the
outside
if you only have the three line wires to test with an Ohmmeter.

Most dual voltage motors are set up for Wye connection because there
are less wires to deal with, due to the internal common connection
already
having been made. A Delta dual-voltage motor needs to bring out all
12 wires, I think. As if 9 wasn't enough!

Jon