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I live in a cheap flat filled with expensive, sensitive electronic devices. There is only one electric circuit for everything to plug in. Several times a day, the fridge's compressor wakes up, and this causes a small dip in power. This is causing trouble with PC components I have already posted about, and also I hear a pop from my cheap PC boxes when happens. Everything is already plugged into a surge-protector power strip, but this doesn't help, probably because the power difference is too small to activate the protection.

Now I am planning to get good, expensive active loudspeakers and don't want them quickly ruined due to power problems. Also, I am afraid for that the power dips are shortening the life expectation of PCs, monitors and peripherals. So I want to find a solution now.

As far as I know, there are two options: an UPS or a voltage regulator. I've never used either, and don't have enough electrotechnics knowledge to know how each works. So I don't know which is better for my situation.

  1. For each device: does it react quickly enough to catch a positive or negative spike in power on its input end and still output level power on the other end, or does it need some time after fluctuations start?
  2. I have already tried to do some reading on both and noticed that there are different kinds of UPS and different kinds of voltage regulators. But I have already forgotten even the basics on voltage and power I learned in sixth grade, so I couldn't understand enough to know which kind would be suited for my case. Can you tell me what kind I need (and, if you know that, how are manufacturers labelling it)?
  3. I don't know how to calculate the capacity I'll need. I tried some online calculator for UPS, but it didn't let me choose all things I am going to plug in. By adding all the wattages of the power supplies, I came up with a theoretical peak drain of 1700 watt, although I think that I don't even reach half of it in a typical usage scenario (1700 W would include turning the boxes' volume to 106 dB). Is there some way to arrive at the proper capacity using this number, and how?
  4. Is there some other feature beside capacity and ability to rapidly react to a power fluctuation relevant to my decision?
  5. Which solution is expected to be cheaper and do the job better (core UPS functions like the opportunity to do a graceful shutdown in a complete power outage are irrelevant to my decision)?

Edit: Just noticed that both UPS and voltage regulators come with power sockets made for PCs and monitors:

alt text.

I want to plug in some things which have a Schuko or Europlug: the external HDDs, the laptop's power supply, and the loudspeakers, as well as a Japanese external sound card (probably through a power converter which also has a Europlug). They are made for this kind of socket:

alt text.

How to solve this, are there adapters or something else?

share|improve this question
there are many adaptor plugs, check google for us to eu plug adaptor. very cheap. Make sure whatever device you buy, that its ACDC power brick matches the volts in your country. eg 230v(europe) or 115v(like us). – barlop Nov 14 '10 at 19:22
@barlop This is generally good advice, but not really relevant to my situation. The UPS and voltage regulators sold here in Europe all provide 230v on their sockets. However, their physical shape only allows connecting PCs and monitors (which come with what Ignacio identified as a IEC connector) and not generic electric devices, which have a Schuko (grounded) or Europlug (ungrounded) connector. Neither is related to a 115v US power plug, for which there are indeed adapters. And non-matching ac/dc bricks are only an issue with grey imports, like the Japanese sound card I mentioned. – rumtscho Nov 14 '10 at 19:55
Well, the good news is that there are Schuko adapters available. The bad news is that the minimum order is 1000 units. – Ignacio Vazquez-Abrams Nov 14 '10 at 21:41
Schuko and computer plug have same internal wiring. There are also extension cables for monitor power cables (they have IEC C13 at one end and IEC C14 at the other). When I was in situation similar to yours, I took one extension cable (similar to this one with Schuko male connector at one end and several female connectors at the other end. Then I removed the part of the cable with male Schuko connector and replaced it with monitor extension cable. It's simple. – AndrejaKo Nov 15 '10 at 8:33
up vote 5 down vote accepted

If you get a UPS, you'll want an "online" or "double-conversion" UPS. The run the equipment off the battery and only power the battery charger from the mains. They offer the best brownout protection possible.

I'm not convinced that a voltage regulator is a good solution, since the brownout is caused by an inductive load. The regulator will pull more current during the brief brownout, and combined with the inductive load this could overload the fuse or circuit breaker.

As for the outlet issue, I'm afraid that I'm in the wrong part of the world to give guidance on that. If it helps, the type of outlet on the regulator in the image is usually called an IEC connector.

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I went with a voltage regulator, because the online UPSes cost half as much as the PC itself. But it has been running for now without problems, and the "hickups" disappeared, so I am staying with it. – rumtscho Dec 4 '10 at 21:29

You need an online UPS as Igancio says.

To measure the actual load you can buy a plug-in power meter that goes between your equipment and the wall socket and shows haw many watts the equipment is consuming at any time. Then just add the wattages for all the equipment to get a rough idea of the size UPS you need. Conrad sell the VOLTCRAFT SBC-500 meter. or the Basetech 3000 (part 125333 - 89)

Conrad also sell a 6-way mains extension for euro-connectors (part Part no.: 631205 - 89) I'm sure they must sell an adapter (or a replacement plug you could fit if competent with 230V electrical wiring). You need the opposite of this Or a German equivalent of this - alas my German Google-fu is too weak.

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The plug-in power meter was a great idea. It also helped me notice what I should plug out at night because it is sucking electricity when the PC is off. – rumtscho Dec 4 '10 at 21:28

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