I'm off to help in some fairly major electrical work -- and by "help," I mean "stay well away from the hot stuff, while doing what I can to ensure that the bare essentials of of what The Starship Company does will, in fact, continue to get done."
You see, we're going to shed as much electrical load as we can, shut down incoming power, kill the standby generator (though the last two not, I hope, in that order; but that's not my department, even though it should be) and run on the big UPSes though what is supposed to be some quick work; then we'll power up the UPS inputs while leaving turned off nonessentials like lights, air-conditioning and the cute little automatic faucets in the washrooms. Oh! And the big coolers in the break area, oopsie. (If you are visiting my workplace next week, might wanna avoid the vendononautomatic, at least the milk, salads and sandwiches. Make 'em take you to one of the places across the street for lunch!)
We're gonna need a whole lot of D cells. The top brass are hoping the big UPSes will be having a really good day; my immediate supervisor, my peers and I have set up a large vehicle with a husky onboard genset and strung hundreds of feet of temporary power wiring to the places that really, really must have juice* and we'll be putting ourselves on shut-off patrol, looking for and powering down any nonessential loads on the UPS we missed prior to the shutdown.
Will it work? I have my doubts; but to the extent that sweat and forethought and keen sense of where we might've slipped up in assigning devices to UPS or commercial power can make it work, I'll be in there trying.
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* Slang, 'Splain Me That Department: wall-socket power and above is "juice" but radiofrequency energy is "the soup." I don't know why, but I'd kinda like to learn the terms steam engineers used for their working fluid; it might be instructive.
BUILDING A 1:1 BALUN
4 years ago
7 comments:
Best of luck, and don't forget your arc/flash protection.
Best of luck to you and here's hoping the UPSs (UPSi?) live up to their spec sheets plus ten percent.
Ditto on the Best of Luck, and hoping no MBA type has overridden someone who actually knows what they're talking about...
A place I worked at a few years back bought a 9 million dollar co-generation system to recover electricity from waste heat going up the smokestack. It was quite the system, state-of-the-art with all kinds of fancy features, like the ability to auto-isolate the plant if the local power utility had a power loss. The system was installed, and a plugs-out test of the system was scheduled.
The big day arrived and the plant electricians simulated a power loss by throwing the knife switches on the utility powerline. The lights briefly flickered as the automated switchgear did its thing.
A few seconds later, a sound come out from the generator house. It grew steadily louder into an un-Godly howl and loud unhappy metal sounds started.
It seems when they installed the system, they thought of everything, including a UPS whose only job was to keep pressurized oil flowing to the *critical* steam turbine bearings until full power transfer occurred.
After the loud, unhappy metal sounds finally stopped, they entered the generator house to figure out what the hell happened.
Only to discover the UPS that powered the oil pump that kept the steam turbine's bearings lubricated...
Was coiled up neatly next to the UPS, not plugged into the wall like it should have been.
Fortunately for the company, the contractor who installed the co-gen plant got to eat that multi-million dollar repair bill.
May your company's UPS test go smoother than the steam turbine's test.
For the want of a plugged in UPS...
No arc-flash needed, we haven't been allowed to open any box not rated "0" since the company realized arc-flash was a thing. The electrical work was all hired-gun electricians.
My part was keeping the gear that (should) run on the UPS going, and supervising the "shutdown patrol" of the stuff that is on UPS but could be turned off to minimize run time.
We were bit, pretty badly, by two different items; one was a poorly-installed bypass switch that was supposed to prevent power-glitch problems and the other was something plugged into non-UPS power. I had come up with a last-ditch fix that bypassed nearly everything. I had not expected to use it but we needed it almost immediately.
It was a very stressful eight hours. Some of our emergency power was via GFCIs, which popped immediately when connected to the switching power supply standalone mini-UPSs we wanted it to run. This required scrambling to find non-GFCI receptacles and adapters to get 20A plugs into 15A receptacles (on 20A breakers and wired with #12 wire; the hardware will handle 20 A but 15A sockets are widely used, so...) (The whole 15/20A receptacle thing is a can of worms and what you should remember is that the plug and socket are not the actual hardware limitation here -- it's the wire size and associated breaker; the plug/socket's lack of downward capability is to keep you from overloading older wiring/breakers.)
There was one more gotcha -- 20A and 30A 120V twist-lock plugs and sockets look a lot alike, especially when you can't unplug the combo that is in use. Because I knew the actual currents, I didn't feel too bad about the 30A-to-Edison-to-20A set of adapters I had to use, but it was ugly.
"UPS" is a lie on the same order as "The check is in the mail" and "one size fits all".
I blame a lot of that statement on the advent of VRLA batteries.
Good to know that you didn't get bit by the usual: finding out that this was the first test of the batteries in those UPS in the 5 years since installation :P Though I expect you're running on real batteries, not SLA like I am. mostly cajun is right.
That reminds me, I should do a test of mine. They are about 3 years old. I can't wait until Li-ion is economical to replace this primitive lead-acid crap.
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