Testing equipment

[ducksoup]

I work in telecommunications and we are looking into backing up all of our (gulp) phone closets as we move slowly to VoIP.

We would like to test the reliability of various UPS's before we make a large investment.

I'd like to look at:
-- Switching time (if not inline)
-- Steady state load test at 0%, 50%, and 100% load, including input and output conditions (voltage/current/frequency)
-- DC to AC efficiency (hrs/VA w/no load)
-- Harmonic output

Has anyone done tests on UPS's before? Anyone have any ideas on how to properly set these tests up so I don't fry anything or cause undue damage to my test UPS's?

Thanks for your help! ~ Andrew

 

[josepablomir]

Well, the easy way is to look at the manufactures data for these parameters.
To buy a digital oscilloscope and/or a power quality analyzer is not cheap. If you are talking about a big investing, the one that could deserve investing in these instruments (see Dranetz, for example), you should call the providers, talk about this, and ask them for test results performed for the manufacturer. You could ask for a customer list, and call and visit some of them. Finally you can talk directly to some engineer at the manufacturing plant, and make a visit to the plant.
Of course, if you are talking about 10 or 20 UPSs of small or medium power, maybe is a better approach to look for high-quality UPSs, and forget about tests and visits. What is small or medium power? Well, below 10 KVA.
In either case, if quality is an issue, you should avoid off line UPSs and go directly for On-Line ones. These will give you no switching time. THD will be, also, lower.
Hope this help.
Regards,
Jose.-


_________________
Pablo Mir
pm@pablomir.com