Hey I need your help.
Recently I bought a Riello NPW 2000 that output a “pseudo-sinusoidal” wave when running on battery the fact is that I read on the web that modern could do like it.
Mostly right as I found that my server (poweredge t430) is not running good with it. When unplugging the power to test the UPS something it make the PC just power off and reboot, or it make the ups in safety mode (continuous beep).
Tried disabling the PFC in IDRAC settings, as far I haven’t noticed power off issues but only safety mode issues with the UPS…
If anyone has an idea… Thank you
Max_P@lemmy.max-p.me 2 days ago
To kind of visually see it, I found this thread of some guy that took oscilloscope captures of the output of their UPS and they’re all pseudo-sines: …anandtech.com/…/so-i-bought-an-oscilloscope.2413…
As you can see, the power isn’t very smooth at all. It’s good enough for a lot of use cases and lower end power supplies, because they just shove that into a bridge rectifier and capacitors. Higher end power supplies have tighter margins, and are also more likely to have more safety features to protect the PC so they can get into protection mode and shut off. Because bad power can mean dips in power to the system which can cause calculation errors which is very undesirable especially in on a server. It probably also messes with power factor correction circuits, which is something cheap PSUs often cheap out on but a good high quality one would have and may shut down because of it.
As you can see in those images too, it spends a significant amount of time at 0V (no power, that’s at the middle of the screen) whereas the sine waves spends an infinitely short time at 0, it goes positive and then negative immediately. All the time spent at 0, you rely on big capacitors in the PSU to hold enough charge to make it to the next burst of power. With the sine wave they’d hold just long enough (we’re going down to 12V and 5V from 120/240V input, so the amount of time normally spent at or below ±12V is actually fairly short).
It’s technically the same average power, so most devices don’t really care. It really depends on the design of the particular unit, some can deal with some really bad power inputs and manage just fine and some will get damaged over long term use.
Pure sine UPSes are better because they’re basically the same as what comes out of the wall outlet. Line interactive ones are even better because they’re ready to take over the moment power goes out and exactly at the same spot in the sine wave so the jitter isn’t quite as bad during the transition. Double conversion is the top tier because they always run off the battery, so there’s no interruption for the connected computer at all. Losing power just means the battery isn’t being charged/kept topped off from the wall anymore so it starts discharging.
magikmw@lemm.ee 2 days ago
This comment tought me more about PSUs and UPSs than my entire experience in IT in a very concise way. Good one.
Bakkoda@sh.itjust.works 2 days ago
I would just not use anything but double conversation. Buy a refurb with new batteries and a solid warranty and don’t worry about it again.
foremanguy92_@lemmy.ml 2 days ago
I think the problem is the PSU of the server (and I think this normal, not a fault of it), will check further