Power Factor and Building Kwh meter

Discussion in 'General Electronics Chat' started by Houdini, Nov 30, 2010.

  1. Houdini

    Thread Starter Member

    Dec 13, 2007
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    I have a few questions about what my facility Utility meter will read. I understand that the meter will only bill me for Real power and not apparent power , is that true.(I do get billed a Power factor penalty if the PF gets too low). But beside the PF Penalty, what would the meter read for the following:

    Euipment runs at 12 amps(on each phase) @480 Volts. The PF is .8. If the machine ran for 1 hour would the Utility meter show an increase of:

    A) (V x I x 1.73 x PF) / 1000 = (480 x 12 x 1.73 x .8) / 1000 = 7.97 Kwh

    or

    B) (V x I x 1.73) / 1000 = (480 x 12 x 1.73) / 1000 = 9.96 Kwh

    eg: Do I use the PF in the equation when trying to determine what the meter will read?

    Thanks
     
  2. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
    1,758
    98
    Ontario Hydro does not charge your home for PF.
     
  3. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    8,754
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    u guys get charged for low PF. :eek:
     
  4. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    No we don't it's not billed to us. Basic electricity is fairly cheap averaging $0.09 per KWH and very reliable. We're also going to or on TOU (time of use) meters that vary the cost depending on time of day. The real expense is "delivery charge" and taxes which can almost double a typical hydro bill.
     
  5. GetDeviceInfo

    Senior Member

    Jun 7, 2009
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    sounds industrial, you probably are being charged apparent, with an additional penalty.
     
  6. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Around here for our commercial building if I don't let my PF drop below 85% then I pay the going KWH, under that they start upping the charge based upon how much lower I am than 85% so your equation needs to take that into account as it isn't X the PF.

    I've got our building running around 98 - 99% winter and 94% summer, if you're only getting 80% you should look into some PFC caps stragically placed near the large motor loads. Saves everyone money, makes your motors run more efficiently and last a lot longer.
     
  7. Houdini

    Thread Starter Member

    Dec 13, 2007
    10
    0
    I just talked to my Energy Supplier and they said they only charge us for Kwh (real power). Then they said the calculation they used was V x I x 1.73 X PF. So the lower the PF the lower the energy cost but you have to be aware that your PF doesn't go below .85 if it does ,they will hit you will a penalty.

    So to make a long story short, I should use PF in my calculation for cost savings but be aware that if the PF drops below .85 I will get an additional charge.

    Also, lower power factor is wasted energy (Which is bad even if you are not paying for it directly) . I agree with marshallf3 on the efficiency of a hight PF.
     
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