UPS Recommendations

Shane Hathaway shane at
Fri Aug 27 01:56:57 MDT 2010

On 08/26/2010 09:40 PM, Michael Torrie wrote:
> Generators bring some interesting things to the mix.  As you say you
> can't have a generator without a UPS.  But the UPS has to be pretty
> smart when switching back and forth between line, battery, and
> generator.  Not only does the UPS have to carry the load while the
> generator gets up to speed, it also has to match phase with the
> generator.  This doesn't take very long, but you have to have a pretty
> expensive UPS to do this.  Then when line power returns, the UPS has to
> carry the load again while it adjusts the phase to match the line phase.
>   We have a nice big, in-line UPS at work that does all this.  Works well
> if you have the resources.

So, for a time, the UPS generates power at a slightly incorrect 
frequency in order to adjust the phase?  That's a cool hack.

I prefer the idea of putting batteries in the computer, though.  It 
works for laptops, why not for servers?


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