Re: Why choose 120 volts?

[Seth Mattinen <sethm () rollernet us>]

Joe Greco wrote:
> > Once upon a time, Joe Greco <jgreco () ns sol net> said:
> > > And I don't like not having anywhere to plug in my power screwdriver's
> > > recharger...  I suppose I should see if I can find someplace that has
> > > a transformer of an appropriate size, or does anyone already have the
> > > part number for something that can provide a few hunderd milliamps of
> > > 120V from 208?  :-)
> > Isn't 208V usually provided as a connection across two phases of a 3
> > phase circuit?  In that case, you get 120V by going between one phase
> > and neutral (no transformer required).
>
> Yes, but this doesn't imply that you have access to those other phases.
> It is easy enough to be delivered 208V single phase service in a data
> center environment.
>
> ... JG

Correct. I have a Smart-UPS RT connected across two legs of 3 phase for
208. The unit does not have a neutral, only ground, so it's 3 wires in
and 3 out. The output is only 208 L-L with odd voltages on L-G. Since
there's no neutral, it can only be used to drive 208 loads or a
transformer for 120.

~Seth