The current drawn by standard low power factor CFLs is not sinusoidal thus normal power factor correction techniques do not work well. Adding inductors and capacitors in the conventional way wont help much.
CFLs draw no current most of the time, just briefly drawing a high current spike, 120 times per second, during 60 Hz sine voltage peaks. Many modern power supplies now use a front end switcher that forces sinusoidal current at the input and thus a very high power factor. This circuitry is now appearing in PC power supplies, many fluorescent lamp ballansts and of course will eventually be in most CFLs. According to others on this site it is already available with some CFLs.
There are two power factors. One for normal inductive loads like motors etc. which draw mostly sinusoidal current, and another for electronic loads which draw non sinusoidal current. CFLs draw very non sinusoidal current. Integrated circuit manufacturers now mass produce ICs that can do a very good job of controlling circuitry to bring power factor to better than 90%, with a minor loss in efficiency and a big reduction in RMS current drawn from the line.
Dimmed to 75% an incandescnet bulb is a very effective heater and an extremely poor illuminator. Incandescent lumens per watt drop dramatically with any voltage reduction. It will use 8x? the power for the same amount of lumen output compared to CFL, and of course provide many years of expensive electric heat without burning out, and of course keep your air conditioner well exercised dumping out the heat during the summer.
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The current drawn by standard low power factor CFLs is not sinusoidal thus normal power factor correction techniques do not work well. Adding inductors and capacitors in the conventional way wont help much. CFLs draw no current most of the time, just briefly drawing a high current spike, 120 times per second, during 60 Hz sine voltage peaks. Many modern power supplies now use a front end switcher that forces sinusoidal current at the input and thus a very high power factor. This circuitry is now appearing in PC power supplies, many fluorescent lamp ballansts and of course will eventually be in most CFLs. According to others on this site it is already available with some CFLs. There are two power factors. One for normal inductive loads like motors etc. which draw mostly sinusoidal current, and another for electronic loads which draw non sinusoidal current. CFLs draw very non sinusoidal current. Integrated circuit manufacturers now mass produce ICs that can do a very good job of controlling circuitry to bring power factor to better than 90%, with a minor loss in efficiency and a big reduction in RMS current drawn from the line.
Dimmed to 75% an incandescnet bulb is a very effective heater and an extremely poor illuminator. Incandescent lumens per watt drop dramatically with any voltage reduction. It will use 8x? the power for the same amount of lumen output compared to CFL, and of course provide many years of expensive electric heat without burning out, and of course keep your air conditioner well exercised dumping out the heat during the summer.