2200VA/3000VA UPS at 220V requires only 15A socket???

Discussion in 'General Electronics Chat' started by Tanster, Nov 26, 2010.

  1. Tanster

    Thread Starter New Member

    Nov 26, 2010
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    I'm trying to figure out why American Power Conversions' specifications for their 2200VA and 3000VA rackmounted UPSes for the 220V market only require 15A feeds whereas their 2200VA and 3000VA rackmounted UPSes for the 110V market require 20A and 30A feeds respectively. Does this make sense? Can anyone explain this to me? Or is it likely a typo in their documentation when it went to the printer? Thanks in advance.
     
    Last edited: Nov 26, 2010
  2. retched

    AAC Fanatic!

    Dec 5, 2009
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    Its because of a fellow named Ohm.

    He has this law. ;)

    Actually, twice as much current is required at half the voltage to do the same work.

    Wattage(work) = Voltage x Amps

    So 2000W (or VA) = 100v x 20 amps

    or

    2000W = 200v x 10 amps
     
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  3. Tanster

    Thread Starter New Member

    Nov 26, 2010
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    Ah! Got it. Duh. Basic physics (and brains) atrophies when not used! :D

    Thanks.

    Which brings me to this next question: What are the advantages and disadvantages in using 110V here in the US over 220V in other parts of the world? From reading some of the threads here, I get the impression that a higher voltage results in less energy lost in the transmission lines (or is that only for extremely high voltages like in the 1,000's of Volts?). Is there a physics-based reason why the USA mostly uses 110V instead of 220V (which is only used for heavy duty appliances like washers and dryers, etc.)? Or does it boil down to similar reasoning why the USA drives on the opposite side of the road from the UK?
     
  4. retched

    AAC Fanatic!

    Dec 5, 2009
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    It makes no sense.

    The distribution line losses are greater at lower voltages. You are correct.

    It is a less efficient system here in the USA.

    I guess the lobbyist for the wire industry had something to do with choosing 120v ;)
     
  5. marshallf3

    Well-Known Member

    Jul 26, 2010
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    You got most of it explained, required input amps x volts - loss in efficiency = watts available at the output. The thing is we don't have outlets and circuit breakers rated for 12.7A or whatever so we just specify the norm that's equal or the next step up.
     
  6. alim

    Senior Member

    Dec 27, 2005
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    I would state a major advantage of the 220v system over the 110v system, and you can converse them. In an installation it is more economical in that the accessories would be less costly. Say, an appliance is rated at 10 amps. at 110 volts that is 1100 watts, at 220v the appliance would be rated at 5 amps, this would result in requiring a lower rated outlet 5 amp vs 10 amp,and a smaller size cable would suffice. If you extrapolate this for an installation large or small you will see the cost savings in switches, outlets, cables, etc. Your main switch/ switch gears would be rated at about 50% of those of a110 v system. It is already stated that there would less losses in the cables.
     
  7. retched

    AAC Fanatic!

    Dec 5, 2009
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    Thats what I meant by the decision was made by the "Wire Lobby". They knew they would sell twice the cable weight if we went 110v
     
  8. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Isn't the home wiring/mains 3 phase in some countries?
     
  9. retched

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    I have never heard of 3 phase for standard residential service.
     
  10. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    In holland you can get a 3 phase connection, if you have an electric furnace / oven.
    Normaly you have a 35 Ampere, 230 Volts single phase power in your home.
    The groups are usualy 16 Ampere each.

    Bertus
     
  11. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    In Czech republic most of places have 3-phase 230V/400V power available.
     
  12. pilko

    Senior Member

    Dec 8, 2008
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    The main advantage of 110V over 220V (or 240V) as it is in the UK is safety.
    Around 7 times as many people die coming into contact with 240V than those coming in contact with 110V.

    pilko
     
  13. Tanster

    Thread Starter New Member

    Nov 26, 2010
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    Uh..."converse" them??? Why would I want to talk to my appliances?
     
  14. Tanster

    Thread Starter New Member

    Nov 26, 2010
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    I'm unclear what you mean: How do "groups" differ from "phases"? I've heard of phases but not groups before.
     
  15. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    You get a main line in house, that is fused with 35 Ampere, but that can only be activated by the power company.
    In house you have a box with a split in several groups.
    Each group powers a part of the house and is fused with 16 A.
    I can reset the 16 Ampere fuses myself.
    You can aslo have separate groups fro the washing machine, dryer, or dishwasher.
    I have 6 groups in my home.
    Three also controlled with a earthleakage controller.

    Bertus
     
  16. Tanster

    Thread Starter New Member

    Nov 26, 2010
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    Ah! I see. And all 3 groups would be in the same phase?
     
  17. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Yes, all groups are connected to the same phase.

    Bertus
     
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