After swapping one of my UPSs for a more powerful model, I have a UPS temporarily surplus to requirements. It has been sitting peacefully in the middle of the room, but if I pick it up, the desire to plug it in to itself and turn it on is tempered only by the desire not to be holding a 45$ ball of flaming plastic.
I’m sure someone knows, or has tried this and can report their observations (though I hasten to add that I don’t encourage new research on this front). Will it cycle on and off rapidly? Refuse to turn on? Start smoking and spray burning electrolyte all over? The manual is disappointingly silent on the subject.
Incidentally, the Belkin 550VA UPS I replaced it with has some cool features - if you tap the power button with the power on, it will perform a self-test. Even cooler, (and I’ve been suggesting this to APC for years), if you do the same thing when it’s on battery power it will STFU and let you shut down programs, fix your electrical setup, etc. w/o beeping incessantly at you.
I actually did this. I guess my will power was less than yours. I don’t remember the model, but it switched on and off a few times then shut down. If I unplugged it from itself it would turn back on.
I was hoping for something more impressive. My next experiment was to use two of them, and hook them up in a loop to see if they would still shut down.
I made a loop out of 9 volt batteries and it got pretty damn hot. My guess is that the UPSs would do the same but hopefully would have a safety feature to shut down before they catch fire.
That’s a completely different situation, since there, the batteries are connected in series. You basically have 18 volts driving your circuit, against only the internal resistance of the batteries, which is pretty darn low (at least, with ideal batteries: Most likely in the real experiment, the batteries aren’t actually putting out a full 9 volts each). The result from Ohm’s law is a heck of a lot of current, and with power = voltage times current, a lot of power dissipated (i.e., heat).
A closer analogy would be two batteries hooked up in parallel, rather than in series: Connect the batteries with male-to-male and female-to-female. This is still not too great for the batteries, but only because they’re not going to be quite identical. And if you additionally put an inverter, transformer, and rectifier in the loop (as with UPSs), you probably wouldn’t have any problem at all (well, no problem beyond the fact that it doesn’t do anything).
My grandfather told me he accidentally plugged his UPS into itself once. He went about playing on his computer, when it finally shut off. It basically acted like it would if it wasn’t plugged in at all. His house stands, so it obviously didn’t turn into a fireball.
Seeing as how everyone was kind enough to post in reply, I decided to perform an experiment. Equipment collected:
-The ‘surplus’ UPS, a Belkin 375VA UPS
2x Belkin 6 port power strips with lighted power switches.
Procedure: The power bars were turned to the ‘On’ position and plugged in to the UPS. One was plugged in to a ‘Surge Protection Only’ outlet, the other in to a ‘Battery Back-up + Surge Protection’ outlet. The UPS will then be plugged in to either of the power bars (or neither) and turned on, and the result observed. The power indicator lights on the power bars will show whether power exists or not.
Hypothesis: Nothing will happen when the UPS is plugged in to the ‘Surge Protection Only’ outlet. Something will happen when it’s in the Powered one.
Result: As expected, when the UPS is turned on, the power bar in the ‘Powered’ outlet lights up, and the other does not. When plugged in to the ‘Surge Protection’ bar, this situation continues, also as expected. When plugged in to the ‘Powered’ bar, the UPS emits a non-stop beep unlike any previously observed, and (very interestingly), the light on the bar goes out. Neither turning the power bar to ‘off’ or unplugging the UPS halts the beeping - the UPS must be turned off before being restored to normal operation.
Conclusion: This UPS contains circuitry to detect loops, and in such cases disables all power output and reports the error condition externally as a non-stop beep. Turning the UPS off and on again resets it to normal operation.
From the anecdotal reports posted previously, it would appear that this behaviour is not universal. The other UPSs in my possession being otherwise gainfully employed, experimenting on other models will have to wait. The universe appears un-rent, but may require furthur equipment to confirm.
Thanks for everyone posting!
I can confirm this. A few months back I was bored at work so I plugged my computer’s UPS into itself. After a few seconds it disappeared in a blinding flash of light. In its place was what I can only describe as a jagged, black tear in the fabric of reality.
I managed to hide the “anomaly” behind some old boxes and a potted plant, and so far, nobody seems to have discovered it (although every once in awhile I hear a comment about the strange draft in the vicinity of my cubicle).
If anybody can tell me how to patch it up, I’d greatly appreciate it. I’d hate to get written up for messing with office equipment. Plus it seems to be growing larger.
