[114846] in North American Network Operators' Group
Re: Why choose 120 volts?
daemon@ATHENA.MIT.EDU (Robert Bonomi)
Wed May 27 20:41:26 2009
Date: Wed, 27 May 2009 20:30:49 -0500 (CDT)
From: Robert Bonomi <bonomi@mail.r-bonomi.com>
To: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
> Subject: Re: Why choose 120 volts?
> Date: Thu, 28 May 2009 01:11:41 +0200
>
> On 27 mei 2009, at 18:03, Peter Beckman wrote:
>
> > I haven't seen a PC power supply which is incapable of both 120v/
> > 60hz and
> > 240v/50hz in a very long time.
>
> After this nice voltage discussion, what about hertz? Would it be more
> efficient for us Europeans to run our stuff at 60 Hz rather than 50? I
> hear that a 50 Hz grid loses 15% more due to inefficiencies than a 60
> Hz grid. Not sure if that also applies over short distances, though.
_Transformer_ losses are greater at lower frequencies. And the cores
have to be bigger.
That is the primary reason military avionics, and other onboard gear
use 400Hz AC.
Note: The U.S. as recently as immediate post WW-II had some areas of
25-Hz power. Transformer based equipment that was designed to be
"just adequate" for 60Hz mains was known to 'let the smoke out' when
plugged in in one of those 25Hz areas.
