There are special dimmable compact fluorescent bulbs, but they are very
pricey. Do these work with regular wall dimming switches? I've seen
suggestions that there are also special dimmers that work with regular
CFL's. Anyone with experience and/or sources for these special dimmers?
I assume its more cost effective to go with one dimmer and the regular
CFL's.

wrote in message
ups.com...
There are special dimmable compact fluorescent bulbs, but
they are very
pricey. Do these work with regular wall dimming switches?
I've seen
suggestions that there are also special dimmers that work
with regular
CFL's. Anyone with experience and/or sources for these
special dimmers?
I assume its more cost effective to go with one dimmer and
the regular
CFL's.


Typically transformer lighting requires electronic
dimmers...not the type used with incandescent bulbs... the
same most likely true with your dimmable fluorescent bulbs.

there should be instructions in the box that specifies the
dimmer... you home depot guy will probably not know, but most
old timers at the electrical wholesale houses would know .


Phil Scott

There are many versions of CFs out there so look out.

1. The ballast is what controls the lamp and therefore the ballast must
be a dimmable type. The lamps are all the same. (Note that almost all
ballasts are electronic these days. Transformers for low voltage
lighting are still magnetic and are very different critters.)

2. Screw-in CF's have very small and usually cheap ballasts built into
them. There are a FEW that are designed to go on a standard dimmer. I
recall that Phillips made a big deal when they release some. As Phil
said: check the box! (and keep your receipts!)

3. Most commercial fixtures can be ordered with dimmable ballasts, but
they usually take special dimmers. They also work a whole lot better,
and more reliably....

So the short answer is; it depends on what your doing. However, a built
in ballast dimmable or not will always save money in the long run!

There is lots of other info on the web. Try:
http://www.eere.energy.gov/consumer/

Richard Reid, LC
Luminous Views
www.luminousviews.com

On 27 Jan 2006 08:40:51 -0800, "
wrote:

There are special dimmable compact fluorescent bulbs, but they are very
pricey. Do these work with regular wall dimming switches? I've seen
suggestions that there are also special dimmers that work with regular
CFL's. Anyone with experience and/or sources for these special dimmers?
I assume its more cost effective to go with one dimmer and the regular
CFL's.

If by "dimmable compact fluorescent bulb" you mean a compact
fluorescent lamp with an integral ballast and an Edison
screw base, and if you live in North America, then the
answer is yes, these are designed to be used with the same
phase cut dimmers used with incandescent lamps. They may not
have the same dimming range as an incandescent lamp, but
that is how they are intended to work.

As for special dimmers for "regular" CFLs." I am a bit
confused. If the "regular CFLs" have integral ballasts and
an Edison screw base, then they cannot be dimmed unless they
are the type described above which are designed to be
dimmed. However, if the lamps do not have integral ballasts
and have instead a 4-pin base then they need an external
ballast and they can be dimmed by using special electronic
dimming ballasts that provide a wide dimming range but are
also quite expensive.

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.

This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.

Victor Roberts wrote:
On 27 Jan 2006 08:40:51 -0800, "
wrote:

There are special dimmable compact fluorescent bulbs, but they are very
pricey. Do these work with regular wall dimming switches? I've seen
suggestions that there are also special dimmers that work with regular
CFL's. Anyone with experience and/or sources for these special dimmers?
I assume its more cost effective to go with one dimmer and the regular
CFL's.

If by "dimmable compact fluorescent bulb" you mean a compact
fluorescent lamp with an integral ballast and an Edison
screw base, and if you live in North America, then the
answer is yes, these are designed to be used with the same
phase cut dimmers used with incandescent lamps. They may not
have the same dimming range as an incandescent lamp, but
that is how they are intended to work.

As for special dimmers for "regular" CFLs." I am a bit
confused. If the "regular CFLs" have integral ballasts and
an Edison screw base, then they cannot be dimmed unless they
are the type described above which are designed to be
dimmed. However, if the lamps do not have integral ballasts
and have instead a 4-pin base then they need an external
ballast and they can be dimmed by using special electronic
dimming ballasts that provide a wide dimming range but are
also quite expensive.

I pretty much agree. But let me add for the sake of pedantry also that
one can dim standard cfls to a limited extent by reducing v_supply, and
reducing v_supply could be achieved by a phase chopping dimmer, though
_not_ the normal pahse shift ones sold for use with incandescents.
Instead it would need to switch o/c during mains v_peaks to charge the
cfl reservoir to lower v. Which implies something other than a triac
for control. But... IRL one would not use that approach.


For the OP, why do you need to dim cfls? In most cases a switchbank is
as effective and more practical than a dimmer. Though not all of
course.


NT

In article .com,
writes:
I pretty much agree. But let me add for the sake of pedantry also that
one can dim standard cfls to a limited extent by reducing v_supply, and
reducing v_supply could be achieved by a phase chopping dimmer, though
_not_ the normal pahse shift ones sold for use with incandescents.
Instead it would need to switch o/c during mains v_peaks to charge the
cfl reservoir to lower v. Which implies something other than a triac
for control. But... IRL one would not use that approach.

I've tried reducing the voltage at the reservoir capacitor, and
it doesn't work. The electronic control gear still feeds the
lamp with constant current over a wide voltage range and so no
dimming happened. When you go outside this range, very strange
things happen. With one lamp, reducing below the threshold
where the control gear could generate constant current, the
current must have increased dramatically as the lamp suddenly
got much brighter. It would likely destroy itself if run this
way for any length of time.

If you remove the reservoir capacitor, the lamp gets dimmer as
you would expect because it's now flickering at 100 times/second
(although not percetably). If you then connect such a lamp to a
phase control dimmer, it does dim over a reasonable range, but
obviously you can't get it to full brightness.

--
Andrew Gabriel

On 28 Jan 2006 03:36:25 -0800, wrote:

Victor Roberts wrote:
On 27 Jan 2006 08:40:51 -0800, "
wrote:

There are special dimmable compact fluorescent bulbs, but they are very
pricey. Do these work with regular wall dimming switches? I've seen
suggestions that there are also special dimmers that work with regular
CFL's. Anyone with experience and/or sources for these special dimmers?
I assume its more cost effective to go with one dimmer and the regular
CFL's.

If by "dimmable compact fluorescent bulb" you mean a compact
fluorescent lamp with an integral ballast and an Edison
screw base, and if you live in North America, then the
answer is yes, these are designed to be used with the same
phase cut dimmers used with incandescent lamps. They may not
have the same dimming range as an incandescent lamp, but
that is how they are intended to work.

As for special dimmers for "regular" CFLs." I am a bit
confused. If the "regular CFLs" have integral ballasts and
an Edison screw base, then they cannot be dimmed unless they
are the type described above which are designed to be
dimmed. However, if the lamps do not have integral ballasts
and have instead a 4-pin base then they need an external
ballast and they can be dimmed by using special electronic
dimming ballasts that provide a wide dimming range but are
also quite expensive.

I pretty much agree. But let me add for the sake of pedantry also that
one can dim standard cfls to a limited extent by reducing v_supply, and
reducing v_supply could be achieved by a phase chopping dimmer, though
_not_ the normal pahse shift ones sold for use with incandescents.
Instead it would need to switch o/c during mains v_peaks to charge the
cfl reservoir to lower v. Which implies something other than a triac
for control. But... IRL one would not use that approach.

Andrew is correct. Many electronic ballasts include at least
some rudimentary feedback that tries to hold the lamp
current constant when the line voltage varies. These
ballasts will hold the lamp current relatively constant over
the input voltage design range, but their behavior outside
this range depends upon the circuit topology. Some will drop
out completely when the line voltage goes too low while
others may not.

BTW - I have tested some of the relatively new "universal
input voltage" ballasts. The ballasts I tested were listed
as suitable for 120 or 240 volts. These ballasts held the
lamp current constant as the input voltage was varied
continuously from about 90 volts to about 280 volts.
Somewhere below 90 volts they shut down but I don't remember
the exact voltage - but it is in my notes if anyone wants
the exact value.

Considering the large number of different circuits that can
be used for electronic lamp ballasts, it is risky to propose
one solution for operation of these ballasts outside their
design voltage range.

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.

This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.

Victor Roberts wrote:

Considering the large number of different circuits that can
be used for electronic lamp ballasts, it is risky to propose
one solution for operation of these ballasts outside their
design voltage range.

Reducing V was not proposed as a solution, more an obervation that it
could be done. It has too many too large issues to be worth doing. And
I cant see the point in dimming them anyway. Dimming seems to be an
unthinking fashion.

The ballasts I played with here dont seem to have any regulation
mechanism that I can see, just oscillate, drive, and cap to bypass the
arc during heatup. I daresay theres all sorts about.

Another possible but not recommended diming method is to wrap
resistance wire round the lamp and connect to power. Increased temps
have quite a dimming effect


NT