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Science Forum Index » Engineering - Lighting Forum » Dimmable CFLs? Spectacular Failures?
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| Author |
Message |
| Justin |
 Posted: Mon Mar 31, 2008 6:03 pm |
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Guest
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Here I am in 120v/60hz land looking for dimmable CFLs. I already have
the CFL dlay problem that annoys my family solved.
Now I'm looking for a CFL that is dimmable and available at Home Depot ,
Lowes or some other store that is common in the US.
Also, when CFLs fail - what happens? Can they catch fire? I know of a
neighbor who had one where the base died and basically melted. I had a
similar failure when I used a normal spiral outside and the bugs piled
up insite the spiral and the thing heated up like a toaster oven and
POOF! There's a burned hole out the side. Now I use an outdoor unit
that is fully enclosed. |
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| Don Klipstein |
| Posted: Mon Mar 31, 2008 6:03 pm |
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Guest
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In article <fsrqk4$sk2$1@aioe.org>, Justin wrote:
Quote: Here I am in 120v/60hz land looking for dimmable CFLs. I already have
the CFL dlay problem that annoys my family solved.
Now I'm looking for a CFL that is dimmable and available at Home Depot ,
Lowes or some other store that is common in the US.
In recent months, I have been seeing GE dimmable spirals at Target.
Quote: Also, when CFLs fail - what happens? Can they catch fire? I know of a
neighbor who had one where the base died and basically melted. I had a
similar failure when I used a normal spiral outside and the bugs piled
up insite the spiral and the thing heated up like a toaster oven and
POOF! There's a burned hole out the side. Now I use an outdoor unit
that is fully enclosed.
CFLs with ballasts in them are normally UL listed. Avoid ones that are
not. I would also get ones of a major brand or of a highly promoted brand
by a major retailer to avoid false claims of UL listing. I have heard of
false claims of UL listing, and even once seen a definite case of this (on
a dollar store extension cord).
In my experience, the main offenders in terms of CFLs failing
spectacularly are the dollar store ones. I would avoid those because in
my experience:
1. Most do not even claim UL listing. One was subjected to a recall for
failure to make the plastic ballast housing out of flame retardant
plastic.
2. Some percentage is DOA or otherwise obviously defective.
3. They account for most of my experience of spectacular failures,
including one that had high smoke output and an orange "burning" glow in
its ballast housing (base area).
4. Their color rendering index is generally lower than that of
non-dollar-store CFLs. Warm color dollar store CFLs, in my experience,
have a spectrum like that of "old tech warm white" - which has the lowest
CRI of any common white/whitish fluorescent lamp.
5. Some have an icy cold "daylight" color but come in packages that say
"soft warm white light". Most that do not state their color are also the
icy cold "daylight" color.
6. In my experience, dollar store CFLs have a 100% rate of falling short
of claimed light output - occaisionally by a factor of at least 3.
7. CFLs with electronic ballasts included are supposed to have FCC
approval. In my experience, most dollar store CFLs lack any sign of FCC
approval, while containing electronic ballasts.
=============================================
My only spectacular failure so far of a CFL that is not a dollar store
one was one of the Lights of America brand, around 2001 or so.
=========================================================
I think your odds of quality in general are slightly improved if the
brand is a "Big 3" brand (GE, Philips, Osram/Sylvania). I also think
quality is likely to be better if the CFL has "Energy Star" approval.
- Don Klipstein (don@misty.com) |
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| Guest |
| Posted: Mon Mar 31, 2008 6:53 pm |
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On Mon, 31 Mar 2008 19:03:30 -0400 Justin <Justin@nobecauseihatespam.net> wrote:
| Here I am in 120v/60hz land looking for dimmable CFLs. I already have
| the CFL dlay problem that annoys my family solved.
| Now I'm looking for a CFL that is dimmable and available at Home Depot ,
| Lowes or some other store that is common in the US.
|
| Also, when CFLs fail - what happens? Can they catch fire? I know of a
| neighbor who had one where the base died and basically melted. I had a
| similar failure when I used a normal spiral outside and the bugs piled
| up insite the spiral and the thing heated up like a toaster oven and
| POOF! There's a burned hole out the side. Now I use an outdoor unit
| that is fully enclosed.
That depends one what kind of failure. Incandescent bulbs would normally
just burn out the filament with a breakage in the filament somewhere.
But I have seen some interesting failures of incandescent bulbs.
In one case, I suspect one of 3 in a fixture burned out, and the surge of
the fault current through the arc being extinguished blew out the others.
All three bulbs suffered various severe damage, including burn holes in
the base, destruction of the filament, and cracking of the glass stem in
one of them. They also had a lot of blackening inside the bulbs, but I
don't know if that pre-existed, or not.
My big worries with CFs are the mercury release risk, and the chance that
cheap electronics could cause a short circuit fault on failure.
Speaking of ovens, I also worry someone will put one inside an oven as a
replacement for a burned out oven light. They used to have standard base
sockets inside (maybe they still do ... I haven't checked in a couple of
decades).
As for dimmable lights, I'd focus on trying to green-ize as many of the
lights that don't need dimming, first, and for now put lower wattage in
the ones that do. Also, if doing wiring to fixtures, make as many of
them independently switchable as possible, so you can turn on the minimum
needed. For now I have CFs on outside lights. I don't like the light
for kitchen duty (I have both Fs and Is in the kitchen, but the Is give
a better quality of light, which I need in the kitchen when cooking or
cleaning).
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / spamtrap-2008-03-31-1825@ipal.net |
|------------------------------------/-------------------------------------| |
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| Guest |
| Posted: Mon Mar 31, 2008 9:07 pm |
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Justin <Justin@nobecauseihatespam.net> wrote:
Quote: Also, when CFLs fail - what happens?
All of the ones I have had that died of natural causes, mostly GE and
Philips lamps, just didn't light up one day when switched on. One of
them made a popping noise when switched on, but that's about it. I've
also had a few that were murdered by having the glass broken, but there
I just got a loud pop (the same one you get when you break any evacuated
bulb) and then nothing.
The ones I have taken apart always seem to have a fusable resistor - a
low-value resistor that is designed to also safely act as a fuse - in
series with the center contact of the base. On a couple of lamps that
died of natural causes, this resistor opened up, probably due to a short
in the main switching transistor in the ballast.
For what it's worth, the Philips Marathon/Universal lamps have (had?)
a better design, IMHO, from a safety point of view. There was a tiny
circuit board (about 0.5" or 13 mm on a side) right in the base of the
lamp that had the fusable resistor, and then some small-gauge lead wires
(less than 18 AWG or 0.8 mm^2) to the main circuit board. The GE lamps
have just one circuit board, with small-gauge lead wires from the base
to the main circuit board; a short on the main circuit board would
result in these small-gauge wires trying to carry all available current
from the house breaker (15 to 20 A) for a brief period of time. Both
the Philips and GE lamps were UL listed, so they both met minimum safety
requirements, but I prefer the Philips design.
Matt Roberds |
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| Justin |
| Posted: Mon Mar 31, 2008 9:24 pm |
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Guest
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phil-news-nospam@ipal.net wrote:
Quote: On Mon, 31 Mar 2008 19:03:30 -0400 Justin <Justin@nobecauseihatespam.net> wrote:
| Here I am in 120v/60hz land looking for dimmable CFLs. I already have
| the CFL dlay problem that annoys my family solved.
| Now I'm looking for a CFL that is dimmable and available at Home Depot ,
| Lowes or some other store that is common in the US.
|
| Also, when CFLs fail - what happens? Can they catch fire? I know of a
| neighbor who had one where the base died and basically melted. I had a
| similar failure when I used a normal spiral outside and the bugs piled
| up insite the spiral and the thing heated up like a toaster oven and
| POOF! There's a burned hole out the side. Now I use an outdoor unit
| that is fully enclosed.
That depends one what kind of failure. Incandescent bulbs would normally
just burn out the filament with a breakage in the filament somewhere.
But I have seen some interesting failures of incandescent bulbs.
In one case, I suspect one of 3 in a fixture burned out, and the surge of
the fault current through the arc being extinguished blew out the others.
All three bulbs suffered various severe damage, including burn holes in
the base, destruction of the filament, and cracking of the glass stem in
one of them. They also had a lot of blackening inside the bulbs, but I
don't know if that pre-existed, or not.
My big worries with CFs are the mercury release risk, and the chance that
cheap electronics could cause a short circuit fault on failure.
Speaking of ovens, I also worry someone will put one inside an oven as a
replacement for a burned out oven light. They used to have standard base
sockets inside (maybe they still do ... I haven't checked in a couple of
decades).
As for dimmable lights, I'd focus on trying to green-ize as many of the
lights that don't need dimming, first, and for now put lower wattage in
the ones that do. Also, if doing wiring to fixtures, make as many of
them independently switchable as possible, so you can turn on the minimum
needed. For now I have CFs on outside lights. I don't like the light
for kitchen duty (I have both Fs and Is in the kitchen, but the Is give
a better quality of light, which I need in the kitchen when cooking or
cleaning).
The reason I want to find a dimmable set of CFLs is not energy
efficiency... but PURE laziness. My parents house has a high ceiling
with two recessed dimmable fixtures. They were ahead of their time in
1973, as modern houses are built exactly like this. The problem is, the
lights are 30 feet up, and when one blows my parents call my sorry ass
over for dinner... and pull an "oh yeah there's the light 30 feet up"
you know the story.
So, I want to swap those out with long lasting dimmable CFLs and I never
shop at the Dollar store. For anything. Only once did I go in there in
college to buy some air fresher because I was farting massively. But
that's another story. |
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| Jonathan Scheuch |
| Posted: Tue Apr 01, 2008 4:46 am |
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Guest
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On Mar 31, 10:24 pm, Justin <Jus...@NobecauseIhatespam.net> wrote:
Quote: phil-news-nos...@ipal.net wrote:
On Mon, 31 Mar 2008 19:03:30 -0400 Justin <Jus...@nobecauseihatespam.net> wrote:
| Here I am in 120v/60hz land looking for dimmable CFLs. I already have
| the CFL dlay problem that annoys my family solved.
| Now I'm looking for a CFL that is dimmable and available at Home Depot ,
| Lowes or some other store that is common in the US.
|
| Also, when CFLs fail - what happens? Can they catch fire? I know of a
| neighbor who had one where the base died and basically melted. I had a
| similar failure when I used a normal spiral outside and the bugs piled
| up insite the spiral and the thing heated up like a toaster oven and
| POOF! There's a burned hole out the side. Now I use an outdoor unit
| that is fully enclosed.
That depends one what kind of failure. Incandescent bulbs would normally
just burn out the filament with a breakage in the filament somewhere.
But I have seen some interesting failures of incandescent bulbs.
In one case, I suspect one of 3 in a fixture burned out, and the surge of
the fault current through the arc being extinguished blew out the others..
All three bulbs suffered various severe damage, including burn holes in
the base, destruction of the filament, and cracking of the glass stem in
one of them. They also had a lot of blackening inside the bulbs, but I
don't know if that pre-existed, or not.
My big worries with CFs are the mercury release risk, and the chance that
cheap electronics could cause a short circuit fault on failure.
Speaking of ovens, I also worry someone will put one inside an oven as a
replacement for a burned out oven light. They used to have standard base
sockets inside (maybe they still do ... I haven't checked in a couple of
decades).
As for dimmable lights, I'd focus on trying to green-ize as many of the
lights that don't need dimming, first, and for now put lower wattage in
the ones that do. Also, if doing wiring to fixtures, make as many of
them independently switchable as possible, so you can turn on the minimum
needed. For now I have CFs on outside lights. I don't like the light
for kitchen duty (I have both Fs and Is in the kitchen, but the Is give
a better quality of light, which I need in the kitchen when cooking or
cleaning).
The reason I want to find a dimmable set of CFLs is not energy
efficiency... but PURE laziness. My parents house has a high ceiling
with two recessed dimmable fixtures. They were ahead of their time in
1973, as modern houses are built exactly like this. The problem is, the
lights are 30 feet up, and when one blows my parents call my sorry ass
over for dinner... and pull an "oh yeah there's the light 30 feet up"
you know the story.
So, I want to swap those out with long lasting dimmable CFLs and I never
shop at the Dollar store. For anything. Only once did I go in there in
college to buy some air fresher because I was farting massively. But
that's another story.- Hide quoted text -
- Show quoted text -
You should check the website for your power company to see if they
have an on-line store for buying energy efficient products. I have
purchased quite a few CFLs from the store associated with my power
company, including four dimmable reflectorized CFLs. These are
replacements for R30 lamps. They work great except for two aspects:
1. They don't dim down to totally off, only to about half brightness.
2. They have a noticable warmup period. When you turn the lights on,
and turn the dimmer switch up to max, the lamps are noticably dim.
After few minutes warmup they reach full brightness can then be
adjusted to the desired brightness.
Those negatives being mentioned, I still love saving energy by using
them. |
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| Bob |
| Posted: Tue Apr 01, 2008 7:31 pm |
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Guest
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<mroberds@worldnet.att.net> wrote in message
news:eNgIj.101901$Ft5.35182@newsfe15.lga...
Quote: Justin <Justin@nobecauseihatespam.net> wrote:
Also, when CFLs fail - what happens?
All of the ones I have had that died of natural causes, mostly GE and
Philips lamps, just didn't light up one day when switched on. One of
them made a popping noise when switched on, but that's about it. I've
also had a few that were murdered by having the glass broken, but there
I just got a loud pop (the same one you get when you break any evacuated
bulb) and then nothing.
Speaking of the GE dimmable.... I bought three of them to put in a ceiling
fan. I am not impressed. You need to turn the dimmer almost all the way up
to get them to light. Then, even after a reasonable warm up, when you turn
the brightness down on them with the dimmer, you get to about half
brightness - dimmer about at 1/4 - and they start flashing like disco
lights. The technology is not quite ready for prime time. |
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| Victor Roberts |
| Posted: Tue Apr 01, 2008 9:46 pm |
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Guest
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On Mon, 31 Mar 2008 22:24:44 -0400, Justin
<Justin@NobecauseIhatespam.net> wrote:
[snip]
Quote: The reason I want to find a dimmable set of CFLs is not energy
efficiency... but PURE laziness. My parents house has a high ceiling
with two recessed dimmable fixtures. They were ahead of their time in
1973, as modern houses are built exactly like this. The problem is, the
lights are 30 feet up, and when one blows my parents call my sorry ass
over for dinner... and pull an "oh yeah there's the light 30 feet up"
you know the story.
So, I want to swap those out with long lasting dimmable CFLs and I never
shop at the Dollar store. For anything. Only once did I go in there in
college to buy some air fresher because I was farting massively. But
that's another story.
Unlike incandescent lamps, dimming CFLs does not increase
their life, and may even shorten it.
--
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. |
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| Victor Roberts |
| Posted: Tue Apr 01, 2008 9:49 pm |
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Guest
|
On Tue, 1 Apr 2008 20:31:59 -0400, "Bob"
<bobsjunkmail@bellsouth.net> wrote:
Quote:
mroberds@worldnet.att.net> wrote in message
news:eNgIj.101901$Ft5.35182@newsfe15.lga...
Justin <Justin@nobecauseihatespam.net> wrote:
Also, when CFLs fail - what happens?
All of the ones I have had that died of natural causes, mostly GE and
Philips lamps, just didn't light up one day when switched on. One of
them made a popping noise when switched on, but that's about it. I've
also had a few that were murdered by having the glass broken, but there
I just got a loud pop (the same one you get when you break any evacuated
bulb) and then nothing.
Speaking of the GE dimmable.... I bought three of them to put in a ceiling
fan. I am not impressed. You need to turn the dimmer almost all the way up
to get them to light. Then, even after a reasonable warm up, when you turn
the brightness down on them with the dimmer, you get to about half
brightness - dimmer about at 1/4 - and they start flashing like disco
lights. The technology is not quite ready for prime time.
The problem is the interaction of the phase controlled
dimmer and the lap ballast. Dimmable CFLs with on-board
dimming controls work just fine. I personally think we need
to stop trying to use phase control dimmers with CFLs.
--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission. |
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| Justin |
| Posted: Tue Apr 01, 2008 10:36 pm |
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Guest
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Victor Roberts wrote:
Quote: On Tue, 1 Apr 2008 20:31:59 -0400, "Bob"
bobsjunkmail@bellsouth.net> wrote:
mroberds@worldnet.att.net> wrote in message
news:eNgIj.101901$Ft5.35182@newsfe15.lga...
Justin <Justin@nobecauseihatespam.net> wrote:
Also, when CFLs fail - what happens?
All of the ones I have had that died of natural causes, mostly GE and
Philips lamps, just didn't light up one day when switched on. One of
them made a popping noise when switched on, but that's about it. I've
also had a few that were murdered by having the glass broken, but there
I just got a loud pop (the same one you get when you break any evacuated
bulb) and then nothing.
Speaking of the GE dimmable.... I bought three of them to put in a ceiling
fan. I am not impressed. You need to turn the dimmer almost all the way up
to get them to light. Then, even after a reasonable warm up, when you turn
the brightness down on them with the dimmer, you get to about half
brightness - dimmer about at 1/4 - and they start flashing like disco
lights. The technology is not quite ready for prime time.
The problem is the interaction of the phase controlled
dimmer and the lap ballast. Dimmable CFLs with on-board
dimming controls work just fine. I personally think we need
to stop trying to use phase control dimmers with CFLs.
OK... what is a phase controlled dimmer? Is every switch dimmer a
phase controlled dimmer? |
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| Don Klipstein |
| Posted: Wed Apr 02, 2008 12:06 pm |
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Guest
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In <o9i7v3h1bkkgr5fkq479e0g8eoqd8tfajt@4ax.com>, Victor Roberts wrote
in part:
Quote: Since LED replacement lamps will use an electronic
driver, they will have the same problems with phase control
dimmers that we now see with CFL replacement lamps.
I have noticed that cold cathode CFLs tend to be dimmable. I wonder if
part of the problem with dimming hot cathode electrobnic-ballasted CFLs is
not a problem with electronic ballasts in general, but a problem with
particular circuits often used with hot cathode CFLs and not with cold
cathode ones, or with the cathodes being at the wrong temperature when the
lamps are dimmed.
Since cold cathode CFLs so far in my experience tend to be dimmable, I
have hope that LED lighting devices will show a better trend for
dimmability than hot cathode CFLs have.
- Don Klipstein (don@misty.com) |
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| Guest |
| Posted: Wed Apr 02, 2008 12:29 pm |
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On Tue, 01 Apr 2008 23:36:38 -0400 Justin <Justin@nobecauseihatespam.net> wrote:
| Victor Roberts wrote:
|> On Tue, 1 Apr 2008 20:31:59 -0400, "Bob"
|> <bobsjunkmail@bellsouth.net> wrote:
|>
|>> <mroberds@worldnet.att.net> wrote in message
|>> news:eNgIj.101901$Ft5.35182@newsfe15.lga...
|>>> Justin <Justin@nobecauseihatespam.net> wrote:
|>>>> Also, when CFLs fail - what happens?
|>>> All of the ones I have had that died of natural causes, mostly GE and
|>>> Philips lamps, just didn't light up one day when switched on. One of
|>>> them made a popping noise when switched on, but that's about it. I've
|>>> also had a few that were murdered by having the glass broken, but there
|>>> I just got a loud pop (the same one you get when you break any evacuated
|>>> bulb) and then nothing.
|>> Speaking of the GE dimmable.... I bought three of them to put in a ceiling
|>> fan. I am not impressed. You need to turn the dimmer almost all the way up
|>> to get them to light. Then, even after a reasonable warm up, when you turn
|>> the brightness down on them with the dimmer, you get to about half
|>> brightness - dimmer about at 1/4 - and they start flashing like disco
|>> lights. The technology is not quite ready for prime time.
|>>
|>
|> The problem is the interaction of the phase controlled
|> dimmer and the lap ballast. Dimmable CFLs with on-board
|> dimming controls work just fine. I personally think we need
|> to stop trying to use phase control dimmers with CFLs.
|>
|
|
| OK... what is a phase controlled dimmer? Is every switch dimmer a
| phase controlled dimmer?
I've yet to see a wall switch dimmer that says it is able to dim CFLs,
even if just the special class of CFLs known as dimmable.
My understanding of the dimmers in most common use is they clip the AC
waveform in time to limit the average power over time (of a cycle).
Variable transformers could be used, but they are expensive, bulky, and
perhaps less efficient. Still, I wonder if CFLs would dim better with
these than the other types of dimmers.
Personally, I'm holding out for improvements in LED lighting. LEDs can
be switched on and off at much faster rates to effect dimming, or they
can be selectively turned on and off (to light a room you need many of
them, so just turn some off for less light). But this is not likely to
be of any benefit where the need is to replace an incandescent bulb in
an existing incandescent (Edison base) fixture with something that can
be dimmed by controlling the mains voltage AC supply to it.
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
| first name lower case at ipal.net / spamtrap-2008-04-02-1222@ipal.net |
|------------------------------------/-------------------------------------| |
|
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| Victor Roberts |
| Posted: Wed Apr 02, 2008 12:58 pm |
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Guest
|
On Tue, 01 Apr 2008 23:36:38 -0400, Justin
<Justin@NobecauseIhatespam.net> wrote:
Quote: Victor Roberts wrote:
On Tue, 1 Apr 2008 20:31:59 -0400, "Bob"
bobsjunkmail@bellsouth.net> wrote:
mroberds@worldnet.att.net> wrote in message
news:eNgIj.101901$Ft5.35182@newsfe15.lga...
Justin <Justin@nobecauseihatespam.net> wrote:
Also, when CFLs fail - what happens?
All of the ones I have had that died of natural causes, mostly GE and
Philips lamps, just didn't light up one day when switched on. One of
them made a popping noise when switched on, but that's about it. I've
also had a few that were murdered by having the glass broken, but there
I just got a loud pop (the same one you get when you break any evacuated
bulb) and then nothing.
Speaking of the GE dimmable.... I bought three of them to put in a ceiling
fan. I am not impressed. You need to turn the dimmer almost all the way up
to get them to light. Then, even after a reasonable warm up, when you turn
the brightness down on them with the dimmer, you get to about half
brightness - dimmer about at 1/4 - and they start flashing like disco
lights. The technology is not quite ready for prime time.
The problem is the interaction of the phase controlled
dimmer and the lap ballast. Dimmable CFLs with on-board
dimming controls work just fine. I personally think we need
to stop trying to use phase control dimmers with CFLs.
OK... what is a phase controlled dimmer? Is every switch dimmer a
phase controlled dimmer?
Phase control (or phase cut) dimmers cut off the starting
portion of each half-cycle of the 60 Hz (or 50 Hz) power
cycle. In this manner they reduce the RMS voltage used to
power an incandescent lamp. See the diagram at the top of:
http://www.stage-directions.com/backissues/Junejuly2001/lightonsubject.shtml
By increasing the amount of time when the power line is held
at zero, the RMS power to the lamp is reduced and the lamp
is dimmed.
All household dimmers are phase control dimmers. Theaters
often use variable transformers, which are much larger and
much more expensive, but do not cause the lamp filaments to
buzz. Also, theaters were using these variable transformers
long before the solid state switches used in phase control
dimmers were invented.
--
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. |
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| Victor Roberts |
| Posted: Wed Apr 02, 2008 1:01 pm |
|
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|
Guest
|
On 2 Apr 2008 17:29:34 GMT, phil-news-nospam@ipal.net wrote:
Quote: On Tue, 01 Apr 2008 23:36:38 -0400 Justin <Justin@nobecauseihatespam.net> wrote:
| Victor Roberts wrote:
|> On Tue, 1 Apr 2008 20:31:59 -0400, "Bob"
|> <bobsjunkmail@bellsouth.net> wrote:
|
|>> <mroberds@worldnet.att.net> wrote in message
|>> news:eNgIj.101901$Ft5.35182@newsfe15.lga...
|>>> Justin <Justin@nobecauseihatespam.net> wrote:
|>>>> Also, when CFLs fail - what happens?
|>>> All of the ones I have had that died of natural causes, mostly GE and
|>>> Philips lamps, just didn't light up one day when switched on. One of
|>>> them made a popping noise when switched on, but that's about it. I've
|>>> also had a few that were murdered by having the glass broken, but there
|>>> I just got a loud pop (the same one you get when you break any evacuated
|>>> bulb) and then nothing.
|>> Speaking of the GE dimmable.... I bought three of them to put in a ceiling
|>> fan. I am not impressed. You need to turn the dimmer almost all the way up
|>> to get them to light. Then, even after a reasonable warm up, when you turn
|>> the brightness down on them with the dimmer, you get to about half
|>> brightness - dimmer about at 1/4 - and they start flashing like disco
|>> lights. The technology is not quite ready for prime time.
|
|
|> The problem is the interaction of the phase controlled
|> dimmer and the lap ballast. Dimmable CFLs with on-board
|> dimming controls work just fine. I personally think we need
|> to stop trying to use phase control dimmers with CFLs.
|
|
|
| OK... what is a phase controlled dimmer? Is every switch dimmer a
| phase controlled dimmer?
I've yet to see a wall switch dimmer that says it is able to dim CFLs,
even if just the special class of CFLs known as dimmable.
Wall switch dimmers will not claim compatibility with all
dimmable CFLs, since there are multiple areas of
incompatibility. However, certain manufactures make phase
control dimmers that are "certified" to dim incandescent
lamps AND their OWN brand of dimmable CFLs.
Quote: My understanding of the dimmers in most common use is they clip the AC
waveform in time to limit the average power over time (of a cycle).
Variable transformers could be used, but they are expensive, bulky, and
perhaps less efficient. Still, I wonder if CFLs would dim better with
these than the other types of dimmers.
Some would.
Quote: Personally, I'm holding out for improvements in LED lighting. LEDs can
be switched on and off at much faster rates to effect dimming, or they
can be selectively turned on and off (to light a room you need many of
them, so just turn some off for less light). But this is not likely to
be of any benefit where the need is to replace an incandescent bulb in
an existing incandescent (Edison base) fixture with something that can
be dimmed by controlling the mains voltage AC supply to it.
Correct. Since LED replacement lamps will use an electronic
driver, they will have the same problems with phase control
dimmers that we now see with CFL replacement lamps.
--
Vic Roberts
http://www.RobertsResearchInc.com
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| Victor Roberts |
| Posted: Wed Apr 02, 2008 7:51 pm |
|
|
|
Guest
|
On Wed, 2 Apr 2008 22:06:59 +0000 (UTC), don@manx.misty.com
(Don Klipstein) wrote:
Quote: In <o9i7v3h1bkkgr5fkq479e0g8eoqd8tfajt@4ax.com>, Victor Roberts wrote
in part:
Since LED replacement lamps will use an electronic
driver, they will have the same problems with phase control
dimmers that we now see with CFL replacement lamps.
I have noticed that cold cathode CFLs tend to be dimmable. I wonder if
part of the problem with dimming hot cathode electrobnic-ballasted CFLs is
not a problem with electronic ballasts in general, but a problem with
particular circuits often used with hot cathode CFLs and not with cold
cathode ones, or with the cathodes being at the wrong temperature when the
lamps are dimmed.
Since cold cathode CFLs so far in my experience tend to be dimmable, I
have hope that LED lighting devices will show a better trend for
dimmability than hot cathode CFLs have.
- Don Klipstein (don@misty.com)
The first problem is unrelated to the lamps at all. It is
the fact that most ballasts are low power factor and that
alone drives many dimmers nuts.
Then there is another problem unrelated to the lamp, and
that is the fact that many replacement lamps do not draw
enough current to meet the "keep alive" requirements of the
TRIAC. This is especially true for LED-based replacement
lamps since they are generally rated for lower power than
CFLs.
The rest of the problems seem to be related to the operation
of the inverter and are unrelated to the extra windings used
to heat the electrodes.
That being said, I have no idea why your cold cathode lamps
are OK in dimmers 
--
Vic Roberts
http://www.RobertsResearchInc.com
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