Re: UPS failure modes (was: fire at NAC)

[Alex Rubenstein <alex () nac net>]

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Hello,

First off, we're all still alive here. Underlying root cause was a failure
of a capacitor in the rectifier section. We're not sure what actually
caused the failure of the failure of the capacitor, but it resulted in the
internals of the capacitor being ejected from the UPS at such a high rate
of speed, that it dented the front door of the UPS itself, and caused the
door to jump the lock and swing open.

I, personally, have never been a fan of Liebert UPS's. The electrical
engineer that we use seems to share my assessment that Lieberts, at least
Series 300's, are not built as well as the could be.

I have no direct experience with MGE, but I recall several multi-hour
outages in Jersey City Exodus, that I think had something to do with MGE
systems. I don't recall if that was human error, or not. Another negative
there, for me, is that they are French.

We own about 8 or so Matrix 5000's; out of box failure rate is hovering at
about 50%, and failure rate within first month of operation is about 75%.
However, once they pass that barrier, they tend to work. Don't overload
them, they tend to get cranky. We had one shoot flames, once, but that
wasn't assosciated with an overload.

My personal favorite: Exide/Powerware/Invensys 9315's. They just work. I
have two of them, an 80 and a 500. The 80 has been installed for nearly 4
years, and has never, ever dropped the critical load unless instructed to.
The 500 is a recent install, but seems to be doing just fine as well.