What does power factor mean for Flourescent lamps?

I tested an old 20W osram fluurescent bulb with built in ballast and it read 14W 0.75 power factor

A new compact 11W fluurescent bulb read 12-14W 1.00 power factor.

The old 20W bulb was noticeably brighter than the new compact.

Reply to
405 TD Estate
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Many older CFLs will present a somewhat inductive load (as will most linear strip lights). So the peak current will be phase shifted with respect to the peak of the mains voltage.

How were you making your measurements? Some equipment will not be able to make accurate measurements with non unity power factors.

These days the CFLs are usually power factor corrected to be closer to unity and look like a mostly resistive load.

No surprises there then ;-)

Reply to
John Rumm

Nothing to do with relative brightness; another poster has given more details.

Nothing to do with the velocity of the flour, or whether it's self raising, either! :-)

Reply to
Bob Eager

It means the power drawn (14W) is 0.75 times what you would think if you simply measured the RMS current and multiplied by the RMS voltage. So you need to size the wires and fuses as though it was an 18.67W lamp, although you will only be charged for the 14W it really uses.

As already stated, this is nothing to do with power factor.

Reply to
Andrew Gabriel

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