on 06-13-201304:27 PM - last edited on 08-26-201312:25 PM by cboysen
You can find a lot of opinions out there about “modular UPS,” but who can you trust? While some of the features sound cool enough, I just can’t wrap my head around the impracticality of it all. I don’t understand the notion that an arrangement with ten 20kVA UPS can somehow protect my mission critical applications better than a 2N system, or even an N+1 system with an A-B bus.
Looking at the information available, it seems marketers just want us to adopt the concept of “hot-swappable” UPS without question. I don’t know about you, but I want my UPS to work and be properly maintained without the need for swapping anything short of hot and cold air from the data center.
All kidding aside, let’s look at the reality of maintenance. Component wear and failures related to fuses can be the biggest maintenance problems for a UPS system. When it comes to component wear and fuses, hot swappable modules are not cost effective because the standby module of the same vintage is just sitting around waiting for something to go wrong. A blown fuse requires the replacement of the entire expensive module rather than the fuse itself.
While I’m confident everyone can list a hundred more failure modes, it still doesn’t make sense to invest in modules that do not provide proactive support. If I can afford redundant modules, why wouldn’t I put them into load protection services?
Neither the math of reliability nor availability agrees with the modular mentality. More modules mean more parts and more opportunities for failure. Some might argue that the opportunity for failure is offset by the redundancy. However, if you think about this from a customer’s perspective, you’d find that a customer would likely only purchase an N+1 modular system; thus leaving the N as mandatory to support the load. In this case, your mandatory UPS plant “N” has more parts and more opportunities to fail than a more traditional 2N system with its inherent internal redundancies.
I’ve heard the term “pay as you grow”. However, it seems the modular mentality wants buyers to pay now and then again as they grow.
We’d like to hear more about your experience with UPS systems.
What kind of UPS system works for your power needs?
Have you used or do you currently use a modular UPS system? What has been your experience with it?
What can we do to improve our UPS systems and equipment?