Poor electricity

By Jskid ยท 19 replies
Oct 12, 2010
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  1. Hello,

    In the building I have my computer the wiring is poor, for example lights dim when the dishwasher is turned on. Could electrical fluxuation be damaging to a computer? I was looking into surge protector, but a surge is when the voltage goes up, not down (as I assume it does when the lights dim).
  2. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Posts: 3,448   +145

    Yeah that happens, I wouldn't worry about it.
  3. brucethetech

    brucethetech TS Enthusiast Posts: 229

    yes. this can be bad and damage computers. you may need to look into a surge protector that keep the voltage constant to avoid a "brown out" these can be bad for computers over time

    lookup "brown out" and "voltage regulator" for more info. Everybody wont need one of these but if your power is that bad you will surely need to look into this.

    EDIT: I just saw Ithat I said "look into a surge protector that keeps the voltage constant" which makes no sense b/c by definition it would then be NOT considered a surge protector, but if you read past that then you know what I meant. So, I lose 2 point on technicality.
  4. captaincranky

    captaincranky TechSpot Addict Posts: 13,020   +2,549

    A surge protector will do absolutely nothing for LOW voltage. Some modern PSUs are self adjusting, sensing the line voltage and compensating accordingly.

    However, I do believe a UPS would be of benefit here, smoothing out the voltage ripple. I don't know however if there's a discreet trip point with one of these. as I don't need to use one personally. Just a suggestion, you might want to research these things a bit more.

    Some UPS info; http://www.newegg.com/Product/Produ...er=BESTMATCH&Description=ups+backup&x=21&y=32
  5. nismo91

    nismo91 TS Evangelist Posts: 930   +33

    you probably need Automatic Voltage Regulator. Some good UPS like captain mentioned have them integrated. My desktop PC is hooked to a AVR, each time lights dim the AVR would 'click'.
  6. edison5do

    edison5do TS Rookie Posts: 231

    Captain got the point, get a Good UPS that woulb be clicking everytime electricity do that, that way you will have your pc protectet for the UPs and Downs of the lights.
  7. madboyv1

    madboyv1 TechSpot Paladin Posts: 1,471   +375

    To explain a little more, the lights dim when something with a high starting wattage/amperage (refrigerators, compressors, electric washer/dryers, so just about anything with a heavy duty DC motor/pump) starts or turns over, and the mains compensates for it. Depending on the electrical wiring for the household it might not effect your computer, but in most cases it does or it is just better off to be safe than sorry.

    UPS backup unit with AVR is essentially a line conditioner (at the very least, undervoltage and overvoltage protection), surge protector, and emergency backup power all in one, so it's always good to have your computer on one. As for cranky's question about the trigger point, it is different between makes and models, though in the US with 120V lines, it is commonly around +/- 10 or 12 volts before the UPS kicks in to protect from over and under voltage (when on a 230v line I think they follow the same +/- 10 or 12 volt rule of thumb as well). With the APC's Powerchute software (if you have an APC UPS unit), you can actually set at what voltage the UPS will kick in for both cases.

    And that 'click' is the backup unit switching from AC to battery (and vice versa); not sure if it needed to be said but I did anyways. lol
  8. Jskid

    Jskid TS Guru Topic Starter Posts: 346

    Thanks for the info. Can I go with something like this since it's way cheaper than a UPS? http://www.thefind.com/computers/info-automatic-voltage-regulator

    I don't know much about these things, what does line-r mean? Is this one good? http://www.macmall.com/p/1970808?dpno=186880&source=zwb12166

    How come on other websites the UPSs are $100 more expensive? http://ncix.com/products/index.php?minorcatid=1036&subminorcatid=548

    Since I want something to stabalize the power I should get a voltage regulator instead of a UPS?
  9. captaincranky

    captaincranky TechSpot Addict Posts: 13,020   +2,549

    I picked one of these at random and clicked on it. I was led to this Dell page: http://accessories.us.dell.com/sna/...&cs=04&c=us&l=en&dgc=SS&cid=52102&lid=1342490

    Here's their blurb;
    This unit would take care of low voltage, and surge suppression, but obviously doesn't have battery backup. I picked the piece at random, but apparently this is somehow endorsed or sold by Dell, so it's probably decent.

    The tech specs list this units; capacity @ "600 VA" *Volt-Amps). At 120 volts, this is about 500 watts. I'm pretty sure that this spec will vary by unit and by price, so here again, you must determine your requirements, before making a buy.

    The only consideration for you would be to ponder this; whether or not you need battery backup as well, as you should be able to get this function in an UPS. That would take care of all three functions, undervoltage, overvoltage (surge surpression, and battery backup. Buying it piece at at time would either likely cause duplication of function, or higher cost, having 2 or 3 self contained pieces of equipment instead of just one. On the other hand, once the batteries "age out" in a UPS, it will likely be cheaper to throw it away, and spring for a new one

    You should give some thought as to whether you need, or can afford battery backup, before you make your purchase. If you find some UPS's that meet your needs post that link(s) also, so we can have a look.
  10. madboyv1

    madboyv1 TechSpot Paladin Posts: 1,471   +375

    Arguably speaking, it depends largely on your requirements. The reason many of the UPSs you linked to as a search are over $100 is because of their high VA rating (most of them are 1000+), which is more or less designed for high consumer load capacity. Most people can get away with half that or even less if they want simple "emergency shut down time" for the computer ONLY when the power goes out (some UPS manufacturers offer software that can do this automatically for you). Plugging in other stuff to the battery backed plugs (most UPSs have surge only and surge+battery plugs) will increase the strain/load on the unit when under its own power, requiring a higher VA rating if you wish to not reduce your time available on the battery.

    Honestly my last UPS (an APC 650VA) was something like $55 on sale 3-4 years ago, and it's still kicking. With the aforementioned software automatically shuts down my computer after being on battery for 5 minutes, though the battery still lasts 15-20 minutes considering its age and frequent use. A surprise since I am in a brownout/blackout prone area with 60 year old house wiring (probably not even to code lol), and often deal with dirty electricity (ie regular under/overvoltage).

    Best investment on an electronic device for me in that whole time period, and I bought a new computer last year. :lol:

    edit: a slightly better version of captaincranky's link: http://www.newegg.com/Store/SubCategory.aspx?SubCategory=72&name=UPS
  11. Jskid

    Jskid TS Guru Topic Starter Posts: 346

    I seldomly have blackouts, only brown outs. The brown outs occure frequently but mildly. So I'm better off with an AVR than a UPS right? I don't see the point in paying extra for something I'd never use.

    What does VA mean? I'm going to get a new computer so I haven't got the specs for it yet.

    Was there a specific product I should look at or just the page in general?
  12. captaincranky

    captaincranky TechSpot Addict Posts: 13,020   +2,549

    VA is "Volt -Amperes". Any combination of volts times amps totaling the machine's rated output can be handled. "Volt Amperes" equals "watts". So, 600 VA / 120V = 5 Amperes. If you divide by volts, the answer is in amperes. If you divide by amperes, the answer is in volts.
  13. Jskid

    Jskid TS Guru Topic Starter Posts: 346

  14. captaincranky

    captaincranky TechSpot Addict Posts: 13,020   +2,549

    You're showing a link to a "UPS" battery back up / surge supressor unit. I thought that this was what you DIDN'T need! The specs don't say that is has an AVR.
  15. Jskid

    Jskid TS Guru Topic Starter Posts: 346

    Ok I get it now, I thought all UPSs included an AVR :dead:
    I noticed this one said Canadian version. Is there something different about the electricity used in the U.S. vs Canada that makes a difference to the product I buy?
  16. captaincranky

    captaincranky TechSpot Addict Posts: 13,020   +2,549

    I actually didn't think there was a difference. Perhaps it's an issue of certifications. It does list the input as 110 Volts, 60 Hz, which is the same as here in the US

    Read the "Standardization" paragraph on this Wiki page; http://en.wikipedia.org/wiki/Mains_electricity

    An "AVR" is actually an automated form of something commonly called a "Variac transformer", (variable alternating current), whereby different taps are invoked in the presence of differing voltage.

    You're not going to make me type something about transformer theory are you?
  17. Jskid

    Jskid TS Guru Topic Starter Posts: 346

    No I'll stop harassing you. Just one more thing that I'm curious about :suspiciou
    I noticed some AVR say they use a "sine wave". I understand that the voltage fluxuates and it does so in a sign wave pattern. Wouldn't the point of an AVR be to make it a constant voltage and not a sine wave?

    Take this for example http://ncix.com/products/index.php?sku=18837&vpn=TS650B&manufacture=OPTI-UPS
  18. hellokitty[hk]

    hellokitty[hk] Hello, nice to meet you! Posts: 3,448   +145

    No...thats what the powersupply does.
    AC has sine waves, while DC is a horizontal line. The UPS is supposed to provide power in place of your outlet, should something happen, and thus outputs in AC.
    Or am I confused?
  19. captaincranky

    captaincranky TechSpot Addict Posts: 13,020   +2,549

    Apparently you're going to get transformer theory and AC current theory to answer this one question.

    AC (alternating current) begins @ 0 volts increases to its maximum positive potential, decreases to 0 again, then swings to its maximum negative potential, and returns again to 0. So, in one complete "cycle" (Hertz is more widely used today) the voltage is at 0, 3 times, with 1 full excursion positive, & 1 full excursion negative. When a graph is made of this cycle, in house current, the graph has a particular shape, and again in house current, this graphic representation is called a "sine wave".

    Please check this Wiki page; http://en.wikipedia.org/wiki/Sine_wave

    Voltage DIFFERENTIAL is established with a transformer. A transformer will only pass an AC signal, it has no effect on, and will not pass DC (direct current) which only flows in one direction. At it's simplest, a transformer has two coils of wire, a primary and a secondary, which relate to the input (primary), and the output, (secondary).

    In an simple example with house current voltages, suppose we have 100 volts at the wall, but we need 120 volts to run our equipment. If the primary coil of the transformer has 100 turns of wire, then the output would need 120 turns of wire to yield 120 volts output. The mechanical ratio of windings, relates directly to the electrical ratio of the transformer. The 100 turns is a simplified representation, but any physical ratio of windings will always be equal to the electrical ratio produced.

    In our example about house voltages, the ratio is 1 to 1.2. So, if our transformer had 1000 windings in the primary, it would need 1200 windings in the secondary to yield the same voltage differential.

    Please see this Wiki page on transformers; http://en.wikipedia.org/wiki/Electrical_transformer

    Transformer coils can be tapped any where in the windings. If we put a tap in the secondary windings of our original transformer @ 100 turns, then the voltage out, would be equal to the voltage in, since both coils now have the same number of turns in their windings. This is the principle behind the "variac", one of the coils is tapped in many places, and switching to these other taps alters the ratio of the coils, thereby changing the voltage ratio. In an "AVR", this switching is done well, "automatically".
  20. captaincranky

    captaincranky TechSpot Addict Posts: 13,020   +2,549

    Actually, I think he's confused, and you're having a spot if difficulty explaining it. You are correct that a UPS outputs in AC. But we're not dealing with complete loss of power, we're trying to deal with voltage fluctuations toward lower voltages. See my explanation of transformers above, I tried to make it accessible, don't know if that worked out yet.

    So, the power supply does indeed "rectify" AC current, turning the output into direct current.

    But, everything that happens >>before<< the computer side (output) of the PSU, is all AC. That would be from the input side of the PSU, to the wall, (and beyond).

    It's possible that this could be, "much ado about nothing". Many PSUs, (such as the Antec Earthwatts series) are self compensating with respect to input voltages. Accordingly, if we knew what the voltage swings actually were, it would be easy to determine if this excursion fell within the PSUs ability to cope with it.

    I think the only thing that's been missed here, is a brief explanation of a UPS.

    A UPS has batteries in it, which are DC, (as are all batteries), beyond that it's basically a power inverter circuit, which is the same thing as an inverter that you plug into a car cigarette lighter, to get AC house current out of it. An inverter works by converting the low voltage DC from the batteries to AC first, then stepping the voltage up through a transformer. (The transformer wouldn't pass DC, we talked about that earlier). The only added twist so to speak, is the addition of an input voltage sensor circuit, so that it knows when to turn on. (Or start "inverting", if you will).

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