UPS Guied Lines

[BitFuzzy]

I've got 2 server, 1 switch, 1 cisco router, and preferably but not nessarily 1 monitor that I need to keep up in the event of power failure for atleast 30 min.

I'm hoping at the end of the year to be able to install a redundant generator but in for the time being this would be better than nothing.

Any suggestions on which models will meet my needs w/o breaking the bank so to speak?

A second Question:

If a UPS will supply 30min of power, would daisy chaining 2+ increase the uptime an additional 30min per unit?

I've tried figuring this out by going to the various MFG web sites, but their documentation is like reading sterio instructions

Thanks in advance

 

[netmanrick]

Are you in USA ? If so I ASSUME you are 115VAC and 60 Hertz.
Look on the data plate of your equipment for ratings.
I would suggest 1 ups for Cisco router and switch(assuming this a a small switch).
I ups per server. Plan on a maximum of 65% efficiency on the
Delivered load to the equipment.
The generator you mentioned......... plan on keeping the ups
between your generator and the equipment.
Check out the Onan web site about generator specs.


Rick Harris
SC Dept of Motor Vehicles
Network Operations

 

[fs483]

Daisy-chaining two UPSes is not suggested because the output of the first UPS is not a "perfect" sin wave (depending on the technology used by the UPS). This "imperfection" is not noticed by end equipment and will function properly. However, if this "imperfect" signal is fed into another UPS as a source, your second UPS might not accept it and attempt to correct it. This correction can mean supplying the or masking the "imperfect" signal with power from it's own battery thus draining the second UPS before the first one. One way that "can" be done if you want to go the route with two UPSes is to buy a quick transfert switch from APC (probably available with other suppliers). This switch which has 2 power inputs and one output. The output goes to the server and each of the two inputs are supplied by each UPS independantly. In case of power failure to both UPSes, the first UPS will supply juice to the server, meanwhile, the second UPS stays idle because it "technically" does't have any load. When the first UPS dies, the transfert switch will then switch over to the secondary UPS. Here's the product :

http://www.apc.com/products/family/index.cfm?id=14

So far, the largest UPSes that I can find that will work on a standard 120V 15A circuit is the APC 1500VA. Anything larger than that needs a special 20A circuit with a special round connector.

Hope it helps.
akwong