[rescue] adding power redundancy to single power supply systems ?

Steve Sandau ssandau at gwi.net
Mon Mar 24 19:35:24 CDT 2008

> <snip>
>> Since it's APC I assume there is something in there that covers it
>> during the switch. I don't know what happens if you have power
>> coming in at different phases... I assume it sends the glitch thru.
> Dunno about phases (talking above my pay grade ;^), but it seems to
> me that ideally the APC-type unit would essentially be a relay
> feeding into a tiny UPS (a big capacitor?) to provide adequate power
> for the split-second the relay is switching over.

My old boss was telling me about the switch to bring his generator on- 
and offline. He called it something like a "make-before-break" switch. I 
guess the idea was that the new connection was made before the original 
connection was broken, ensuring a constant supply of electricity to the 
load. I'm not sure how that would work since it would connect the two 
power sources, but that is what he described.


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