# Cap maximum wall outlet voltage

I live in a rural area.

A problem occured when my UPS could not run my computer simply because of voltage fluctuations. I have tried many stabilizers but its too rapid that it would make a tick and the UPS would switch to battery then on line after some time it would run out of juice and just decide to shut off.

I now have many stabilizers but none worked. the last fix I can think of is the cap/ throttle the outlet voltage to 100-110 depending the minimum its fluctuating from so the stabilizer won't tick and the UPS neither hence running all day long.

TL;DR: How to Cap / throttle the output voltage a wall outlet to stop stablizer from making a tick, hence running the UPS on line. ANY way even bringing an electrician and do what's described in the answer.

• you want a "online UPS" (in europe this is IEC 62040-3.2.16 class 1) – Andy Nov 10 '18 at 9:57
• The terms APC uses are "Double conversion on-line". – Andy Nov 10 '18 at 10:08
• The UPS I have is specifically for pc uses I have only added a router, monitor and pc on it and since I asked the shopkeeper to give the one only for emergency shutdown cases it did its job on the old house the problem occured when there is electricity in this house but fluctuated voltag – PcTrollGamer Nov 11 '18 at 11:06

You could try using a passive line stabilizer. If the problem is line fluctuations and not constant brief interruptions, these should be able to keep the voltage to your UPS stable.

The technical name is “ferroresonant transformers”. These are relatively large and have a limited output power (they use passive components to store energy after all). But these should work well for a small computer load, and have no active circuitry to misinterpret what the line is doing.

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A similar device a “constant voltage transformer” is a transformer with multiple output taps, and active additional electronics to switch among the taps as needed. It is much more efficient and economic but being active might be an issue.

• Salam, I've marked your answer as correct so anyone coming to see would help him well this is all around the best answer as the cost is ~30-35$is my country and thanks, will try to talk to buy this. Secondly the name you gave was for ~200$ but a similar product "Constant Voltage Transformer" is for ~30-35\$. So you can reply whether its right. – PcTrollGamer Nov 11 '18 at 11:25
• @PcTrollGamer I updated the answer. From your description of the problem I am not sure if that would work. A constant voltage transformer has no energy storage, while a ferroresonant transformer can “ride” across a couple skipped cycles as it discharges its storage tank. If your problem is brief overvoltages triggering the ups electronics, then make sure the specifications of the transformer can address those spikes, but if it is interruptions it will not. – Edgar Brown Nov 11 '18 at 14:50

How to Cap / throttle the output voltage

Long story short: You can't. Basically, the power grid's sole job is keeping the voltage on the grid stable.

You could build something like

fluctuating AC outlet -> Step-down AC/DC Converter -> Stable lower-voltage DC -> Inverter -> stable AC

But that's exactly what an online UPS is: add a stabilizing battery to the DC circuit, and you've got one!

So, you'll need a better grid (which you won't get anytime soon, I guess) or you need a better UPS.

• That’s not really what a commercial UPS is. A commercial UPS is rally an IPS. Terminology be damned. – Edgar Brown Nov 10 '18 at 11:17
• @EdgarBrown well, yes. But the point I'm trying to get across to OP is that if his UPS doesn't catch the case of an unstable primary, well, the UPS is insufficient. – Marcus Müller Nov 10 '18 at 11:34
• Well, technically you are right but of course the point of you're answer is so I can the the point my UPS does fine. I don't have problem with my UPS and you're right too I won't be getting a nice grid either so its a lose lose situation for me :(. – PcTrollGamer Nov 11 '18 at 11:09
• no, your UPS doesn't work fine at all. It clearly says so in your question! – Marcus Müller Nov 11 '18 at 11:14