Personal computing discussed
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Erazor GTX wrote:Some background information: Right now, I have my computer (including monitors and all peripherals) plugged into a UPS. It's a 750 W Cyberpower unit that I bought new about 2 years ago. I'm not sure if it has automatic voltage regulation, but the software that is installed with the UPS is programmed to go on battery power if voltage gets too low or high.
The UPS should protect you from anything the PSU can't handle. Lack of AVR (if you don't have it) isn't the end of the world, all it means is that you'll be dipping into the battery power whenever there are voltage fluctuations; as long as the voltage fluctuations aren't happening constantly (causing the battery to drain), it shouldn't be much of an issue.
Does the UPS actually switch to battery power when the lights dim during AC unit switching? If it never switches to battery power - then the voltage drop is probably not dangerously low and I wouldn't worry about whole thing.
Ryhadar wrote:Sorry to hi-jack the thread a bit but I've got a similar situation. Would a good surge protector help with this?
Also, I have a good power supply (Seasonic x650), but if the surge protector won't help, will the PSU take any damage from this behavior?
Ryhadar wrote:Sorry to hi-jack the thread a bit but I've got a similar situation. Would a good surge protector help with this?
Also, I have a good power supply (Seasonic x650), but if the surge protector won't help, will the PSU take any damage from this behavior?
Which means the voltage seen at the outlet is about 105V for that same tenth of a second, which is more than enough to create a visible flicker for all devices connected on that branch. I've simplified by ignoring the inductive reactance of the wire, which will not affect a steady-state load very much, but will temporarily add even more resistance when that 60A surge is briefly demanded. So the actual voltage at the outlet might be down below 100V when the A/C unit starts.
Just to make sure that I understand correctly: In my case, I'm still OK because the UPS that I have modulates the incoming voltage and makes it more constant. If it were to drop below 90V, the battery would kick in for that little bit of time, as set by the UPS software. Is this the right way to think about this?
ludi wrote:Not likely, unless your UPS cost somewhere north of $1k.
Ryhadar wrote:*Phew*
Even with every turned on in the room my computer is in I never saw my multimeter read anything below 115V.
I'm glad I learned about this though, but looks like I'm going to go without buying an AVR. Though, it might not be a bad investment for my router, ATA, modem, etc...
Thanks again for the help,
Erazor GTX wrote:So, I guess the question becomes: what do I do, if anything? Do you all recommend that I upgrade to a better UPS?
Dimming should not happen. Assuming you have calculated the load of everything on that circuit, then serious dimming implies a wiring problem.
Erazor GTX wrote:So, I guess the question becomes: what do I do, if anything? Do you all recommend that I upgrade to a better UPS? If so, which one would be a good investment? This is the one I have right now: http://www.ebay.com/itm/GEEK-SQUAD-875VA-GS-875U-UPS-BATTERY-BACK-UP-SYSTEM-USED-/150720341604. It's getting a little bit long in the tooth, but it still works really well.
Edit:
I found this power supply: http://www.cyberpowersystems.com/products/ups-systems/adaptive-sinewave-series/CP1000PFCLCD.html
It's a line-interactive UPS (for frequent undervoltages) that's compatible with Active PFC PSUs. Would this be a good upgrade, or am I better off going with something more high-end?
ludi wrote:Incorrect. Flicker can occur on a properly-sized circuit for any device that generates a large inrush current. Continued flicker during operation, or a sustained dimming, would indicate a serious circuit problem. The OP has indicated that the flicker only occurs when the AC unit starts, and that the circuit voltage with the AC unit running is only a couple volts lower than without that load. Both behaviors are within normal operating conditions.
westom wrote:If voltage drop is only a few volts, then dimming is near zero.
ludi wrote:If the voltage on a branch circuit briefly dips to 105V during a compressor start, ...
ludi wrote:Westom, you are arguing against a phantom.