Why choose 120 volts?

Dave Larter dave at stayonline.com
Tue May 26 18:58:18 CDT 2009


Yes, you are correct Chris.  The loss from getting 240 from two legs is
due to the fact that it is at 120 instead of 180 deg's.

-----Original Message-----
From: Chris Adams [mailto:cmadams at hiwaay.net] 
Sent: Tuesday, May 26, 2009 7:52 PM
To: Joe Greco
Cc: nanog at nanog.org
Subject: Re: Why choose 120 volts?

Once upon a time, Joe Greco <jgreco at 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).

You need a NEMA 14 (4 wire) connector to get two phases, neutral, and
ground (provides 1 208V circuit and/or 2 120V circuits) or a NEMA L21
(5 wire) connector to get all three phases, neutral, and ground
(provides 3 208V circuits and/or 3 120V circuits).

-- 
Chris Adams <cmadams at hiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.





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