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John Rumm John Rumm is offline
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Default What does power factor mean for Flourescent lamps?

405 TD Estate wrote:

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


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.

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


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

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


No surprises there then ;-)

--
Cheers,

John.

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