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A reading of "64.5" on a 40w CFL? Find out why! The reading of 64.5 here is measured in voltamps, which you get by multiplying the voltage and current. This CFL has a power factor of only 52%, so the voltamps is almost double the actual wattage (it recorded around 35w, despite the 40w rating). The power consumed is still 35w, but the total voltamps include all the current wasted by the low power factor. Since the good old incandescent bulb has a power factor of one (or 100%), both the watts and voltamps are identical in value. All CFLs have this power factor problem, in fact all inductive loads have this problem. A capacitor helps balance this out, but CFLs dont have them because there isnt room for one. Keywords: Miscellaneous

A reading of "64.5" on a 40w CFL? Find out why!

The reading of 64.5 here is measured in voltamps, which you get by multiplying the voltage and current. This CFL has a power factor of only 52%, so the voltamps is almost double the actual wattage (it recorded around 35w, despite the 40w rating). The power consumed is still 35w, but the total voltamps include all the current wasted by the low power factor. Since the good old incandescent bulb has a power factor of one (or 100%), both the watts and voltamps are identical in value. All CFLs have this power factor problem, in fact all inductive loads have this problem. A capacitor helps balance this out, but CFLs dont have them because there isnt room for one.

m8_17_imlbdb_26_08.jpg m8_17_imlbdb_15_44.jpg P1010015.JPG Stuff_003.JPG IMG_0002.JPG
File information
Filename:P1010015.JPG
Album name:Silverliner14B / The rest
Keywords:Miscellaneous
Filesize:129 KiB
Date added:Oct 05, 2011
Dimensions:2048 x 1536 pixels
Displayed:128 times
Color Space:sRGB
Contrast:0
DateTime Original:0000:00:00 00:00:00
Exposure Bias:0 EV
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Exposure Program:Program Creative
Exposure Time:1/800 sec
FNumber:f/4.5
Flash:No Flash
Focal length:5.9 mm
ISO:64
Light Source:Unknown: 0
Make:Olympus Optical Co.,ltd
Max Aperture:f/2.8
Model:C730UZ
URL:http://www.galleryoflights.org/mb/gallery/displayimage.php?pid=8688
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Comment 1 to 8 of 8
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Form109   [Oct 05, 2011 at 06:30 AM]
does this present some sort of problem?
joe_347V   [Oct 05, 2011 at 07:23 AM]
I wonder if the new "smart meters" can detect poor PF which will allow the PoCo to charge residential customers more if they have a poor PF.
streetlight98   [Oct 05, 2011 at 10:59 AM]
See? CFLs suck no matter what. Razz Rolling Eyes
rjluna2   [Oct 05, 2011 at 11:30 AM]
You might want to explain this to the myopically Bureaucrat who don't know about a squat about energy saving bulbs Razz
Form109   [Jan 31, 2012 at 06:45 AM]
nobody ever awnsered...does this present a problem of any sorts?
TiCoune66   [Aug 29, 2012 at 02:00 AM]
It just draws more amps. It can be a problem if you run lots of them since quite a bit of power is wasted.

I wonder if the poor power factor is caused not by an inductive component, but by a CAPACITIVE component. There are in fact few inductors inside a CFL ballast (and they're small, plus they run at pretty high frequencies). However there's always a large capacitor after the bridge rectifier that directly converts the 120V AC into 170V DC.

There would be something interesting to try to confirm my theory. Run a certain inductive load (like a NPF fluorescent ballast), then add a few CFLs in parrallel to see if current DROPS of RAISES.

If raises --> CFL is also inductive

If drops --> CFL is in fact CAPACITIVE!
joe_347V   [Aug 29, 2012 at 03:27 AM]
Interesting idea Vince, Using your idea I tested some CFLs and it does seem to support the idea that the poor PF in a CFL is caused by a capacitive component.

GE 16W Magnetic Preheat CFL
(Inductive Load)
Cat No. FLB 17

I: 0.24A
P: 15W
VA: 28.8
PF: 0.52

Philips 13w Marathon Mini Twister
(Capacitive Load)
Cat No. EL/mdt 13W

I: 0.13A
P: 12W
VA: 15.6
PF: 0.76

Panasonic 14W CFL
(Capacitive Load...appears to have some kind of PFC)
Cat No. EFU14E28

I: 0.12A
P: 13W
VA: 14.4
PF: 0.90

NOMA 13W Twister
(Capacitive Load)
Cat No. FLE13HT3/2/NOMA

I: 0.11A
P: 10W
VA: 13.2
PF: 0.75

GE 16W Magnetic Preheat CFL + Philips 13w Marathon Mini Twister

I: 0.33a
P: 36W
VA: 39.6
PF: 0.90

GE 16W Magnetic Preheat CFL + Panasonic 14W CFL

I: 0.31A
P: 30W
VA: 37.2
PF: 0.806

GE 16W Magnetic Preheat CFL + NOMA 13W Twister

I: 0.30A
P: 29W
VA: 36VA
PF: 0.805

It seems that pairing a typical electronic CFL with a magnetic NPF one will raise the overall PF of the two lamps but some lamps will work better than others at correcting the PF. Also it appears that PF of electronic CFLs varies between makers...the Panasonic one had a impressive 0.9 PF by itself.
A_lights   [Aug 29, 2012 at 04:24 AM]
litetronics makes HPF Cfls

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