Eudimorphodon
Veteran Member
This thread brings back fun memories of the time the 400KVA Liebert UPS we had in the basement datacenter went nuclear and exploded its battery bank.
(I'm fuzzy on the exact details, I wasn't the one who got to talk to the electrician in the aftermath, but my vague recollection was that the series of events went something like: a: street power went out and the UPS, which was technically slightly overloaded with all the crud hanging off it, took over the immediate load while the two minute(ish?) start timer on the generator outside was triggered. b: Generator started, sailed through its warmup, and the signal was sent to the cutover circuitry to feed the generator power into the UPS's input, and c: the street power came back on at exactly that second and *somehow* this resulted in a giant power surge forcing its way through the UPS and caused an instant boilover on a full rack of batteries.
Again, I totally could be garbling the why, but whatever happened it was spectacular and expensive. We're lucky nothing actually caught fire, I guess.)
(I'm fuzzy on the exact details, I wasn't the one who got to talk to the electrician in the aftermath, but my vague recollection was that the series of events went something like: a: street power went out and the UPS, which was technically slightly overloaded with all the crud hanging off it, took over the immediate load while the two minute(ish?) start timer on the generator outside was triggered. b: Generator started, sailed through its warmup, and the signal was sent to the cutover circuitry to feed the generator power into the UPS's input, and c: the street power came back on at exactly that second and *somehow* this resulted in a giant power surge forcing its way through the UPS and caused an instant boilover on a full rack of batteries.
Again, I totally could be garbling the why, but whatever happened it was spectacular and expensive. We're lucky nothing actually caught fire, I guess.)