UPS
- Thread starter j rae
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JDBrown
Senior Member
- Location
- California
- Occupation
- Electrical Engineer
It really depends on what the equipment is, and what you mean by "an extended period of time." APC has a nice little calculator on their website to help you determine how big of a UPS you need based on your load and runtime needs. You'll also want to look into whether or not your equipment needs a UPS with a sinusoidal output, or if a modified square wave is okay.
Also, I've heard of some issues with specific combinations of UPS and load equipment, where the equipment ends up tripping one of the safety features on the UPS. In the case I'm thinking about, I believe the problem had to do with the UPS performing a self test and then shutting down if it wasn't loaded to within a certain percentage of its capacity. The UPS was designed to work that way, but the people trying to troubleshoot the problem didn't know that at first.
Anyway, the point is, before you decide on any specific UPS, you have to do your homework. Find a model that you think will work for your application, and then contact the manufacturer to have them confirm that it should work for you, and to find out if there are any "special features" that might trip you up. After that, it's sometimes beneficial to call back at a different time of day in hopes of getting a different individual on the phone -- it's amazing how often tech support people for the same company contradict each other.
Also, I've heard of some issues with specific combinations of UPS and load equipment, where the equipment ends up tripping one of the safety features on the UPS. In the case I'm thinking about, I believe the problem had to do with the UPS performing a self test and then shutting down if it wasn't loaded to within a certain percentage of its capacity. The UPS was designed to work that way, but the people trying to troubleshoot the problem didn't know that at first.
Anyway, the point is, before you decide on any specific UPS, you have to do your homework. Find a model that you think will work for your application, and then contact the manufacturer to have them confirm that it should work for you, and to find out if there are any "special features" that might trip you up. After that, it's sometimes beneficial to call back at a different time of day in hopes of getting a different individual on the phone -- it's amazing how often tech support people for the same company contradict each other.
weressl
Esteemed Member
The main feature of UPS versus other backup power sources is that it provides virtually uninterrupted power to the critical equipment. Should a less-than quarter cycle interruption cause trouble fro the critical user, such as data or configuration loss, reboot, then indeed you require an UPS grade backup. Prolonged backup times run into hour(s) are usually not a cost or even reliable backup options unless you are installing redundant systems. Your best bet is to back up the UPS with an emergency generator, have a 10-30min battery backup from the UPS and let the generator supply, recharge the UPS.
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