Hi again all,
All of this talk made me curious about power factor and CFL bulbs, so I did a little searching. I have linked one of many articles that attempt to explain how power factor effects the actual (price paid) power:
PDF article on CFL Power Factor .
I am converting my lighting to CFL with the idea of saving energy. Realizing that a 23 Watt CFL with low (typical) power factor might actually cost about 40 Watts of power is a bit of an eye opener. Fluorescent lighting is still very efficient (lumens/watt) but all of the hype gets dulled a little with some more accurate information. I have read, but cannot verify, that meters in the US actually measure Volt Amps. If that is true, then the extra costs comes out of my pocket.
That makes me even happier to discover these 'purespectrum' high PF bulbs.
Ken
One added thought:
Many lawmakers are trying/going to force most all of us to replace existing incandescent bulbs with CFLs. That would be less painful if the same lawmakers would put a requirement on CFL manufacturers to meet some minimum efficiency/noise requirement. I would also be in favor of forcing them to list the 'actual' power of these devices.
k
Hi Ken,
This is exactly what got me excited about your 'purespectum' bulbs when you posted. While I have extensive experience with Power Quality in an aircraft environment, I have very little experience with traditional electric grid distribution. While the concept is the same, the end goal is entirely different.
As you noted, there has been a huge push to convert to lower power appliances and lighting. While this has lightened the power load on the electrical grid, but it is coming at a cost. The proliferation of electronic loads cause power to be consumed entirely differently than what the power systems were designed for. The reduced power factor and increased distortion creates other loading problems for transformers and utilities. It can also (as we well know) create havoc for powerline communications.
Previously, Power Factor was not a consideration for residences (factories are charged based on their PF consumption) . Most of the loads in homes consumed power in phase and didn't add significant harmonics. That is changing. Europe has already adopted standards for PF and THD of electronic devices. We are a bit behind the curve.
CFL's have traditionally had extremely poor Power Factors and high THD. Even so, they are not nearly as disruptive as higher power electronic devices like plasma TV's and switching power supplies on computers/UPS's/Audio. For that reason they have been flying below the radar. In general, CFLs appear to be a good thing for the power grid. While the may have horrible PF and THD, the relative reduction in power consumption does help our power distribution system. The effects on residences can (again) be entirely different from a power quality viewpoint.
I was impressed by the product that you posted because:
1) To my knowledge, there is no legislation requiring high power factor/low THD CFLs. The trend appears to be in the opposite direction. Smaller bases (nicer fit) with higher THD.
2) Your observation that this bulb functioned down to 1% with a 2-wire dimmer - this manufacturer is trying hard to make a dimmable CFL that is compatible with existing "standard" dimmers.
3) The bulb is a higher lumen version (75W equivalent) and appears to be reasonable in cost - even though it appears to be very new.
In short, this manufacturer is stepping up and providing a CFL that operates like a standard incandescent (high PF, low distortion, full dimming range, 2-wire compatible). I've been waiting for year for this. I can only hope that other manufacturers will follow suit.
I happened to come across a site that rated CFL's and LED's some time ago. Very interesting reading. Most of the reports stard in the 2000 time frame where THD was in the range of 130%. To my surprise, CFL THD has gotten worse in recent years. Not the direction we'd like to be headed for our powerline systems.
The following is a series of reports on screwbase CFL's that is freely available:
http://www.lrc.rpi.edu/programs/NLPIP/PDF/VIEW/SR_SB_CFL.pdf
The site itself is located here:
http://www.lrc.rpi.edu/programs/NLPIP/index.asp you'll need to register to download test reports (Email).
Edit - I am one slow poster:
WayneW - I agree that all of the residential services that I know of are charged based on "true" (in phase) power.
Ken - The 40W quoted in the article that you cited is the Volt-amp equivalent. While you shouldn't be charged for it, the power company has to supply it. This can result in a capacity issue for your power supplier.
As a side note, some of the reports that are cited above show THD values in excess of 200% for CFL's (things have gotten worse over the years). There also does not appear to be a pattern by manufacturer (i.e. manufactures provide both high and low PF bulbs within their range of products).