Once Bitten: the saga of computer power supply protection [part 2]

This is the second post in a series of three.  Read the previous post on surge suppressors.

POWER CONDITIONING & VOLTAGE REGULATION

In theory, your wall outlet is supposed to deliver a steady, predictable source of current to the devices plugged into it, free of fluctuations.  In practice, this is not always the case, for a dozen different reasons:  the time of day, the demands on the grid, the way the wiring and appliances are set-up inside your house.  Plug your air conditioner and a lamp into the same socket and watch the lamp dim when the air-conditioner kicks in;  you’ll get the idea pretty quickly.  Any attempt to deal with straightening these sorts of fluctuations out is loosely referred to as power conditioning (or sometimes line conditioning;  in my case, and probably yours, the attempt  is going to start at the wall socket, not at the pole outside.)

Surge suppression, discussed in my earlier post, is one kind of power conditioning.  (Technical authors like to use the extended name of “transient voltage surge suppression”;  the distinction must be important to them for some reason.)  Other kinds include:

• Filtering, to get rid of noise (little random variations in the power that are inherent in all electricity), and RFI/EMI (“radio frequency interference” and “electromagnetic interference” respectively, both of which are names for the effect of outside or nearby energies on the line).
• Voltage regulation, to correct under-voltages (sags and brownouts) and over-voltages (spikes and surges)
• Isolation, which is removing the physical connections between the different parts of your power system so as to create a barrier against problems.  (This seems to be more in the engineering province, relevant only to site-level installations and the insides of transformers, but the principle is simple enough-  a surge that fries your wireless hub isn’t going to fry the laptop using it, for example.)
• Harmonic cancellation, which is technical, and of which my understanding is currently incomplete.  Essentially it seems that unaddressed harmonics in the electrical wave have the potential to give you some of the other problems already mentioned:  over-voltage, etc.

A power conditioning system then, will engage in some combination of these strategies, in order to make the current headed to your device more like the predictable output it’s supposed to be.  And this leads in turn to the obvious question:  do you, the electronics owner, NEED such a system?

Weeeeeeeeeellll…  that’s where it gets tricky.  Apparently it depends on who you talk to…

Audiophiles and home theatre owners spend a lot of time growling about power conditioning, with some justification:  weirdness and interference in the power supply can translate into funny noises and distortions in the picture.  I’m not an audiophile or a home theatre owner, so I can’t discuss that in anything except vague, general terms.  I know I got weird ghosting on my TV, when I had TV, and that on my house phone line you can generally hear a number of other conversations going on in the background (in a variety of languages, no less,) and that it’s fairly annoying.  So if a power conditioning system is going to solve those kinds of issues for you, Godspeed.

For a computer owner, on the other hand, the relevant question is, “What effects are these sorts of variations going to have on my equipment?”  The answer is, “Bad ones,”-   but the response question, “How bad?” is where the discussion begins to get maddeningly nuanced.  A quick Web search will turn up many sites issuing dire proclamations about how all these inconsistencies in your electrical supply are going to adversely affect the performance of your electronics and damage them, shortening their functional lifespan.  Not coincidentally, these are also usually sites of companies that sell power conditioning equipment…

Let’s consider voltage regulation as an example.  Generally, everyone seems to agree that voltage outside of the parameters your equipment is expecting is Bad.  At one point, powered electronic devices were using linear power supplies, requiring a very specific incoming voltage, so aberrant voltage had the potential to be Very Bad.  Nowadays, however, linear power supplies have been partially or totally replaced by switched-mode power supplies, which are able to handle a much wider range of incoming voltage without batting an eye.  That makes over and under-voltage less of a problem-   BUT switched-mode power supplies apparently generate more harmonics.  Also, a switched mode power supply responds to an under-voltage situation by drawing more power to compensate, increasing the amperage, which in turn throws off more heat (heat being the Universal Enemy of All Electronics.)  An external power conditioning system that includes voltage regulation prevents the computer’s power supply from having to do this-  BUT any such system is probably going to generate its own heat (and noise, and also probably draw power itself for its own functions).  But that heat is environmental heat and not inside the electronics you’re trying to protect…  and on and on it goes.

Similarly, one can find anecdotal evidence to support either the need or the lack of need for power conditioning as one desires.  Erratic power supply is likelier in the area of institutions with heavy draw, such as hospitals and factories.  From my attic apartment, I can look out one window at the hospital, and out the other at factories–  and my system ran for more than four years of daily use without any external power conditioning before it toasted, losing in that time only a video card (and that after three years).  On the other hand, the idea that a lack of power conditioning was contributing to the demise of the system would help explain why the older mother board was fried by the surge, but the comparatively newer video card and monitors were not.  My friend Schnallity down the road has never had a power failure during the time he’s been living there, nor any brown-outs that he’s aware of–  but he’s had enough cards and drives fry for no good reason that it’s obvious something is adversely affecting his systems.  So has my friend Sudre, who lives a time-zone away from me, owns multiple computers and is an electrician;  his power systems (installed after the kills) provide under-voltage correction, but not over-voltage correction.  (I have an e-mail in to him asking why he’s OK with this being the case;  as of this writing, his reply is still pending.)

In the end, this topic is the one about which it has been difficult for me to draw any solid conclusions.  If the electricity where you live has shown a demonstrable tendency to flake out, or if you’ve had prior experience losing equipment–  and if you have the spare cash to spend–  then the extra protection and peace of mind might very well be worth it.  If not…  who’s to say?  You pays your money and takes your chances.

“Sag, schmag!” I hear you saying.  “None of this will help me when the power just turns off!  What am I supposed to do then?”  Well happily, that’s a lot easier to straighten out.  Step on over to topic 3:  uninterruptible power supplies.

—

If you have read this article, and you believe that I am seriously off-base or factually in error about any of the above information, please leave a comment and tell me!  I will happily revise it, and learn from my mistakes.