Generator install - where to start

[WinterDeere]

One, see if you can adjust the input power acceptance settings on your UPS to allow a larger input power spread (+/-VAC, and a larger frequency spread).

Yes, all UPS's had already been set to widest possible tolerance range, or in APC parlance, "lowest sensitivity". But given how shady APC is with all of their specmanship and vague literature, I'm honestly not sure what parameters are being adjusted. Voltage bounds only? Frequency? THD? No idea...

Two, spend a little time with your Firman to make sure the frequency is set correctly (my suggestion would be to try for 61.5-62Hz unloaded), but try to see what works with your loads, and to dial the voltage up a bit to allow for the distance from the generator to your load and for the resulting voltage drop.

Being the classic engineering nerd, you just know that I adjusted the governor on my genny to hold 60 Hz. It as running 64 Hz out of the box, but the governor on this one actually works really well and holds steady. After adjusting it down a bit, I see it holds a near-perfect 59.5 - 60.5 Hz under all steady load conditions.

I'm not aware of any voltage adjustment mechanism. The onboard display reads 245 volts, so a hair high, but still in 240 ± 5% tolerance range. I have not checked balance on this one though, nor have I checked to see how equally both legs are loaded.

I also haven't gone so far as to hook up and check THD, spurrs, or noise, but I easily could with my o'scope. That said, hopefully I won't be relying on this stupid generator much longer.

So, I can't guarantee that your new generator will make the UPS happy, but possibly, even probably, as the new generator probably has a better voltage regulator, and probably a larger rotor, which adds to the stored energy, which helps keep voltage and frequency within specifications. Adjusting the UPS parameters will probably help a lot, and may even completely solve your issue of the UPS switching on/off line faster than it can charge.

Are any of the installed generators of the inverter type, or are they all old-school induction motor types?

I recommend Eaton UPS units. They aren't inexpensive, but they are in my experience rock solid, and have the ability to adjust a wide variety of parameters for the specific needs of a site.

I should look at them, when it comes time to replace the current fleet. I actually used to buy very large industrial 3-phase UPS's, so I'm quite familiar with the options and technologies out there. I used to really like the 3-phase inverter type UPS's made by JDSU, as your equipment was never connected to the mains, there was no switching and no possibility of transient pass-thru. But they cost like $25k each for small rack-mount units 25 years ago, I can't even imagine what they'd cost today.

I used to also buy 100,000 - 300,000 VA UPS's to run our test labs. They were the size of Euro refrigerators.

I went with APC here, because they were quick and cheap, when I was starting a new self-funded business. They get the job done, but maybe aren't the most robust option when trying to run off a dirty generator.

 

[WinterDeere]

Oh, and I learned that the power outage was caused by someone having a "medical emergency" behind the wheel. Took out a pole, flipped their car, and landed in the front yard of one of my daughter's former teacher and babysitter. A right big mess.

No word on the driver, hope they're okay. Looked like the car had about a million airbags deployed, as it sat on its roof in the ditch alongside the road.

 

[ning]

Yes. Most of my simulation runs are actually under 30 minutes, but optimizations or parameter sweeps taking hundreds or thousands of consective runs are common. Yesterday's chore was one such task, 234 iterations of a simulation task that was probably only 10 minutes.

It presently runs on a 32-core Xeon machine, which is a power hog, but with one big UPS for the PC and a few more smaller UPS's for networking hardware and NAS, I usually have at least 30 - 40 minutes runtime on the PC and many hours for network and NAS. This has always been plenty of time to set up my portable generator, such that there's no interruption.

That was with my old generator, which blew up last year. I replaced it with a Firman, only thing I could get in a pinch, and the UPSs just will not stay happy on that genny. They constantly toggle, and apparently lose charge faster than gaining it, to the point where the workstation shut down about 3 hours into yesterday's outage.

This is one of my biggest concerns with a $10k permanent generator install... will my UPS's be happy on it? I have four critical UPS's in the house, between workstation, networking hardware, and vector network analyzer, and several others that are less important. I can't have them toggling hundreds of times per hour between battery and generator source.


The software handles distributed computing and MPA, more for splitting between multiple large-scale workstations, than any small Raspberry Pi clusters. But it adds about $10k per node per year to the leasing cost, and usually the benefit is negligible... sometimes even negative. The trouble is the overhead required to split the calculation task onto multiple nodes is high enough to undo the benefit of parallelization larger than that already built into a reasonable 24 - 64 core Xeon machine.

Some of the solvers also support GPU. In fact, I ran it for many years on two workstations (distributed), each workstation having Tesla K80 GPU's. This was back in the days when the best solvers ran memory-bound processes that could take 100 hours to solve on the best multi-core x multi-socketed CPU's. Then it was worth the processor and networking overhead to split a solver process onto multiple machines, and even port to GPU's.

But today's solvers are more efficient, and the latest Xeon CPU's are so much faster, I don't really see much need for all of that overhead anymore. Oh, and starting this year, the software lease comes with many hours of cloud computing, which allows me to port the rare very-large-scale task onto their cloud. I haven't had need for that, in the short time it's been available, single solver runs that take long enough (> 2 hours?) to require that, are fairly rare.

Seems like you may be well-served by a partial house battery backup system (ie, your office/LAN/NAS), which itself may be recharged with a generator. Could be easier to count that as business expense as well, separated from the rest of the house.

 

[JRH02]

What's the problem? We've been off for 16 years. The electronics isn't the problem. It's the rest of your life's consumption. It's that getting in the way of your work.