Evan wrote:
On May 27, 11:03 am, "Stormin Mormon"
wrote:
I've had the moment to work on 440 volt roof top heating and AC.

Once in a while, need some power to run a 120 volt device. Is it 120
volts from one leg to ground?

(Yeah, I could just check it. But I was on the roof yesterday, and not
sure how long until I get to another roof.)

--
Christopher A. Young
Learn more about Jesus
www.lds.org
.


How old is this roof top unit... Seriously 440 volts ? Are you sure
that it isn't 480 volts ?

I asked the _age_ of the unit because there is supposed to be
a service outlet for 120 volt powered tools for maintaining the
roof top equipment installed somewhere near the unit...

And no, with a 3 phase 480 volt system it is typically 277 volts
on each leg...

~~ Evan

Usually, equipment is rated for a range of voltages. A lot of HVAC
equipment has different taps on the 24 volt control transformer to
pick a different primary voltage. I've seen some air handlers that
had a tap on the control transformer for 110 volts and another for
120 volts. Of course on larger package units there will be taps on
the primary of the control transformer to choose between 208 or 240.
I've seen a lot of blower motors that show a rating of 100-125 VAC
60 Hz on the nameplate.

TDD