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Reducing current

  1. Jun 19, 2011 #1
    Good day !!!

    Just want to ask help of my inquiry:

    1. Is reducing a non productive current (reactive current) of a particular load in Alternating Current could save energy? meaning less current means less demand on the electric meter so the result of this reduced current is the slow spin of the meter? is this true?
     
  2. jcsd
  3. Jun 19, 2011 #2

    uart

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    Simple answer: No, the "electric meter" records only the real power.

    More details: For industrial customers yes the power factor may be monitored and tariff increased if reactive current is too high (PF too low). Most domestic installations however are only charged for real power. Applying PF correction will save some energy loss in the transmission system of your energy provider if you want to do that for altruistic reasons, but they wont credit you for it.
     
  4. Jun 19, 2011 #3
    http://intellicontroller.com/ [Broken]

    What can you say about website above? they claimed that they can reduced electric consumption.....
     
    Last edited by a moderator: May 5, 2017
  5. Jun 19, 2011 #4
    It's an industrial (shunt) capacitive power factor corrector. If your factory is inductive, this capacitor will correct it at the plant before the utility bills you extra for poor power factor.
     
  6. Jun 19, 2011 #5

    uart

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    To quote from that website :
    Exactly what I said previously. Large consumers and industries are frequently charged (in the way of increased tariff) if their power factor is too low. So yes it can save them money. This is part of their energy supply contract, an example might be something like 15% reduction in the rate (cost/kwh) if the PF is kept over 0.85.

    In most countries normal domestic consumers do not have contracts such as the above. In fact they don't even have their reactive power individually measured.
     
    Last edited by a moderator: May 5, 2017
  7. Jun 23, 2011 #6
    apart from power factor, they claimed it reduced a copper loss. My question is how much percentage usually the loss energy of motors?
     
  8. Jun 23, 2011 #7

    uart

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    It will not change the copper loss of your motor or other equipment. It will reduce the copper losses in the transmission line that bring the power to your house.
     
  9. Jul 5, 2011 #8
  10. Jul 5, 2011 #9
  11. Jul 5, 2011 #10
    It would be really great if you could type out what the contents of the video are. What claims are you asking us to verify?
     
  12. Jul 7, 2011 #11

    davenn

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    Interesting display. Honestly, I have no idea if its a scam or not.
    I didnt go searching for what the unit costs. Would be interesting to know that
    and whether it would be worth the risk trying one out.

    I guess I could always ask them for a onsite demo at my home before deciding to buy.
    If they declined, then I would be VERY suspicious

    Dave
     
  13. Jul 7, 2011 #12

    MATLABdude

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    I'd love to know what principle this Go4Green EnergySmart Power Saving Device Plug thing operates upon.

    It claims to:
    • allow you to plug it in at any point in your electrical network (single phase only)
    • to reduces the electricity bill for your entire house, not just those things that are on the same branch, or at the same outlet
    • reduce real power consumption by 14%
    • "[optimize] the power supply to match the design requirements of household/office appliances decreasing distribution losses which dissipate power in the form of heat. Since this power cannot be returned o the electrical circuit, it is lost power which is paid by you!!!" (This from an eBay listing I found for the unit)

    It looks too small to be an adjustment capacitor (assuming Australia meters reactive power), I have no idea how it can depress the voltage level by 14% (without dissipating it as heat), nor do I know of a way to reduce the resistance of the copper wiring.
     
  14. Jul 7, 2011 #13

    davenn

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    The old saying come to mind..... " if it looks too good to be true, then it probably is "

    D
     
  15. Jul 7, 2011 #14

    uart

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    Yes the OP (energysaver) seems to be convinced, but I'll like to ask him where he believes the extra energy is coming from given that the "green plug" device generates no real power. The pixies at the bottom of the garden? The good power fairies?

    Here's my thought on those videos.

    - No independent verification is the big stand out feature. The guys doing the 'testing" are the guys promoting it.

    - Australia meters only real power consumption in domestic installations.

    - You can generate reactive power fairly compactly using a bidirectional AC/DC converter with a large electrolytic on the DC side. Presumably they're doing something like that.

    - If the device only generates reactive power then the best it can do is to reduce the copper losses between the device and the metering point. (That is, copper losses within the house wiring).

    - The power circuit wiring in Australia would typically be around 5 to 8 milliohms per meter. So a 30 meter return loop would amount to approx 0.18 ohms. Now lets say that that 2000W was at 0.7 PF. The current would have been approx 11.9 amps and at best about 8.35 amps after correction. So we could conceivably get R x delta I^2 of about 13 Watts there. This compares with about 150 Watts difference that they measured.

    Possible causes for the discrepancy are :
    1. Very long or undersized wiring to deliberately distort the results. That is, deliberately using high wiring resistance.
    2. Use of a power meter that is inaccurate when measuring real power in the presence of a reactive power component.

    One final comment on the second of the two videos. The household loads measured over those half hour intervals are NOT constant. A/C's refrigerators pool pumps etc can all cut in and out, so there is no reason to believe that the first and second half hour intervals had exactly the same loads present. Furthermore there is no guarantee, even if the video wasn't edited, that they didn't repeat that test 10 times before they got the results that they wanted. Which really brings me back to my first point of the need for independent testing.
     
    Last edited: Jul 7, 2011
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