[CentOS] Emergency rescue help needed

[tech]

John R Pierce wrote:
> all the BackUPs I've ever seen have been simple relay switched units.    
> when the power is on,  you're getting unfiltered power (except for a MOV 
> based surge protector), when the power is out, it switches to the 
> "modified square wave" inverter output.

John,

There are units that change the AC to DC. The DC then charges the 
batteries and gets changed back to AC for the equipment. These units are 
very expensive though.

The relay switching types, like you mentioned, have response delays. 
They can let transients through. These transients can cause weird PC 
problems. I know, I have one of these and still a lot of transients get 
through to my equipment. My local service is very unreliable. The power 
company uses a funny set of definitions about transients so that they 
can claim their power is good.