Tim: >> I have a UPS sitting next to me, right now, in pieces, which (half) >> died in a most peculiar manner: >> > >> While running off the mains its output is a (too) low voltage, but >> still high enough for most switch-mode power supplies to run >> normally (i.e. the computer and monitor). It has some kind of AC >> voltage regulation built into it to deal with under and over- >> voltage. The AC supply was normal, at the time. >> >> But running off its battery it produces the full 240 volts it's >> supposed to. > Roger Heflin: > If you read about normal UPSes they are not normally designed to run > 100% duty cycle (ie on battery for days, or fixing up a low voltage > for days). So if you run yours at say 40% load it will probably > survive under the higher duty cycle, but if you run it close to 100% > load and it gets into cleaning up low voltages the UPS electronics may > not survive long (ie if fixing the voltages for hours/days). Its a Sola 0310-0400 A. The UPS is specced for 188 to 264 Vac in, intended for a normally 220-240 volt AC supply. Outputs a modified sinewave, of 230 Vac up to 2.35 amps max, 1.91 amps nominal, 400 watts (VA) output, or 250 watts (taking power factor into consideration). Able to power a full load for 4 minutes, 15 minutes for a half load. Which all sounds like tax accountant maths, pitched by a used car salesman. I live in a 240 volt country, the mains here is generally 240 to 245 volts. In general, it just sits there coasting along on easy street. The mains is close to spec 99% of the time. The computer only uses about 40 watts, the monitor a bit less (when it's on, next to nothing when off, which is mostly is). Light duties with a very basic system. The UPS draws about 16 watts from the wall when running without a computer attached (maintaining its fully charged battery, I haven't tested it recharging a flattened one). And always humming like it went deaf at Woodstock (it's always been a loud hummer), with extra buzzing when its running off its battery. As I recall, when I assessed it years ago it did what I expected it to do, as far as output voltages are concerned. After the recent failure, the AC output when mains power is present is around 180 volts, but returns to 240 when running on battery. That was tested with a computer as a load, and then separately with an 60 watt incandescent load (the simplest load I could think of to non-stress test it). While 180 volts is enough to power the computer equipment without them being stressed about it (they use universal power supplies meant for 110 to 240 volt countries). It's clearly faulty, and I tend to think it's done its duty and earnt its retirement. > There is also a setting on at least some UPSes that you can change Unfortunately, it's got no user controls (beyond the on/off and start/test switches), nor any internal adjustments. The only changeable thing is an unidentified 3 pin header with a jumper on it. I could only venture a guess that the jumpered one is possibly a 50/60 Hz default output selector. Ordinarily it detects what the mains does, and follows that. But a cold start running off the battery with no mains always starts running at 50 Hz. While I can easily test moving that jumper, I'm not going to do potentially nasty electrical work at 1 am. Now for the kicker, having said I won't mess with mains in the wee hours: I forgot about the jumper, but I just poked around with the UPS now, measured some unwanted resistance on the relay changeover terminals. Unsoldered it, poked at the terminals by themselves, it got better. Resoldered it back in. Mains power goes through at full voltage, battery generated AC output is low. I may just have a crapped relay. It's a potted one, where you can't see the contacts. That's a part I can easily replace to see what happens. -- NB: All unexpected mail to my mailbox is automatically deleted. I will only get to see the messages that are posted to the list. The following system info data is generated fresh for each post: uname -rsvp Linux 6.1.14-100.fc36.x86_64 #1 SMP PREEMPT_DYNAMIC Sun Feb 26 00:31:11 UTC 2023 x86_64 _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/users@xxxxxxxxxxxxxxxxxxxxxxx Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
