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Re: Why choose 120 volts?


From: Robert Bonomi <bonomi () mail r-bonomi com>
Date: Wed, 27 May 2009 20:30:49 -0500 (CDT)

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.



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