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Why CLF dimmables may not dim.

Posted by bugbite (My Page) on
Fri, May 29, 09 at 16:55

This is from the Neptun Dimmable CFLs Operating Instructions, but is an insight into why dimmables may not dim.
? Unpack and install your new Neptun Dimmable CFLs
? It is recommended that you use the same model and wattage Neptun lamp on any one
? It is also recommended that you do not leave any incandescent or halogen light bulbs on
that dimmer once you have installed the Neptun Lamps, (doing so does NOT create any
type of hazard, rather it simply may interfere with the functionality of the dimmable
? The very first time you turn on your new Neptun Dimmable CFLs it is recommended
that you let the bulbs "burn in" for at least one hour. (Subsequent start-ups should only
require a 1 to 2 minute warm up before proper dimming can be achieved.
? After the initial one hour burn in, you may dim the lamps in to any level you desire down
to 10% and the lamps can be left at the dimmed level of your choice for as long as you
? Dimmers with decreased mechanical ranges may not dim the lamps all the way down to
10% and dimmers with extended mechanical ranges may dim the Neptun CFLs to a point
where they turn off.
? The Bulbs stay bright even as the dimmer is adjusted to the lowest level.
o Some dimmers do not have enough of a mechanical range to dim compact
fluorescent light bulbs. Dimmers available on the market today have not been
designed to work with dimmable CFLs, rather Neptun designed dimmable CFLs
to work with available dimmers. However, some dimmers lack the mechanical
range to dim bulbs that are only 16 watts when they were originally designed to
dim 100W bulbs. When this is the case you may not see any dimming from the
CFL even when you slide your dimmer to the bottom of its range, at which point
you may call Neptun directly for a recommendation on a replacement dimmer.
? When dimmed to the lowest level, some of the bulbs turn off and some stay on and/or
some of the bulbs flicker.
o Unlike incandescent light bulbs, CFLs have up to 30 electrical components
inside each bulb. The numerous diodes, transistors, capacitors and so on, all have
slightly different tolerances which makes it very difficult to make the lowest
level exactly the same in every lamp. However, as the lamps burn in and age, you
will see more uniformity from the bulbs at the low end. Also, letting them warm
up longer provides better uniformity at the lowest dimming levels.

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