Power Factor and Building Kwh meter

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

Dec 13, 2007
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0
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
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98
Ontario Hydro does not charge your home for PF.

3. R!f@@ AAC Fanatic!

Apr 2, 2009
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u guys get charged for low PF.

4. blueroomelectronics AAC Fanatic!

Jul 22, 2007
1,758
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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
1,571
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sounds industrial, you probably are being charged apparent, with an additional penalty.

6. marshallf3 Well-Known Member

Jul 26, 2010
2,358
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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.