They are so on and off! I bought a ceiling light for my daughter's
bedroom with around 6 halogen (20w) in it. When you switch it on, you
are lucky if 4 of them come on. If you fiddle with the rest they
usually come on eventually, but once switched off, you are back to the
same scenario with at least two not working when you flick the switch.
In the bathroom I have 2 over the wash basin. One is fine, rock solid,
the other comes on if it feels like it.
Can anyone explain why this is to me?
is there an answer?
Sooooooo tedious. I think I'll go back to a single 150 w bulb till
they are impossible to find.

Mikeyboy wrote:

They are so on and off! I bought a ceiling light for my daughter's
bedroom with around 6 halogen (20w) in it. When you switch it on, you
are lucky if 4 of them come on. If you fiddle with the rest they
usually come on eventually, but once switched off, you are back to the
same scenario with at least two not working when you flick the switch.
In the bathroom I have 2 over the wash basin. One is fine, rock solid,
the other comes on if it feels like it.
Can anyone explain why this is to me?
is there an answer?
Sooooooo tedious. I think I'll go back to a single 150 w bulb till
they are impossible to find.

There's a really bad batch of Chinese 20W bulbs doing the rounds
(assuming 12V?).
It's not a problem with the bulb pins or fitting holder contacts
(although some fiddling can get it lit again), it's a fault in the
bulb itself, where the filament is badly spot welded to the connection
wire inside the glass enveleope. Heating and cooling exacerbates the
problem until failure.
Aldi are doing packs of 20W spares at the moment.

Mikeyboy wrote:
They are so on and off! I bought a ceiling light for my daughter's
bedroom with around 6 halogen (20w) in it. When you switch it on, you
are lucky if 4 of them come on. If you fiddle with the rest they
usually come on eventually, but once switched off, you are back to the
same scenario with at least two not working when you flick the switch.
In the bathroom I have 2 over the wash basin. One is fine, rock solid,
the other comes on if it feels like it.
Can anyone explain why this is to me?
is there an answer?
Sooooooo tedious. I think I'll go back to a single 150 w bulb till
they are impossible to find.

OK, six times the likelihood of a problem then. My MIL has them in her
kitchen and she has the same experience. I have never been keen on these
sort of fittings - seem more like "style" than beneficial. Time to replace
with a good CFL.

I'll get my coat.....

OK, six times the likelihood of a problem then. My MIL has them in her
kitchen and she has the same experience. I have never been keen on these
sort of fittings - seem more like "style" than beneficial.


Time to replace with a good CFL.

I'll get my coat.....


There's no such animal ... d;~}

Arfa

There's a really bad batch of Chinese 20W bulbs doing the rounds
(assuming 12V?).
It's not a problem with the bulb pins or fitting holder *contacts
(although some fiddling can get it lit again), it's a fault in the
bulb itself, where the filament is badly spot welded to the connection
wire inside the glass enveleope. Heating and cooling *exacerbates the
problem until *failure.
Aldi are doing packs of 20W spares at the moment.

No it is nothing recent - I've had these lights for about 3 years now,
and daughter has been at uni in this time which is why I maybe haven't
raised it before. Not down to chinese bulbs.

"Arfa Daily" wrote in message
...



OK, six times the likelihood of a problem then. My MIL has them in her
kitchen and she has the same experience. I have never been keen on these
sort of fittings - seem more like "style" than beneficial.


Time to replace with a good CFL.

I'll get my coat.....


There's no such animal ... d;~}

Arfa


Possibly burned contacts in the holder.

Mikeyboy expressed precisely :
They are so on and off! I bought a ceiling light for my daughter's
bedroom with around 6 halogen (20w) in it. When you switch it on, you
are lucky if 4 of them come on. If you fiddle with the rest they
usually come on eventually, but once switched off, you are back to the
same scenario with at least two not working when you flick the switch.
In the bathroom I have 2 over the wash basin. One is fine, rock solid,
the other comes on if it feels like it.
Can anyone explain why this is to me?

I'll assume 12v, as these seem to give most trouble....

At 12v the current is close to 2amps and the contacts of the lamps
socket can overheat and become poor/intermitant. Nudging the lamps in
the holders often overcomes the poor contact for the duration that they
are still turned on, but as they cool the contact goes bad again. In
which case replace the sockets and affected lamps with new.

2nd possibility...

If the filament burns out, you can often tap the lamp and get the
filament to make contact again for the time they remain on, the fix is
new lamps.

3rd possibility...

If the 240 to 12v transformers (SMPSU) see no load at switch on, they
can shut themselves down. This might apply to both of the above
scenarios.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

On 14 Feb, 09:21, Harry Bloomfield
wrote:
Mikeyboy expressed precisely :

They are so on and off! I bought a ceiling light for my daughter's
bedroom with around 6 halogen (20w) in it. When you switch it on, you
are lucky if 4 of them come on. If you fiddle with the rest they
usually come on eventually, but once switched off, you are back to the
same scenario with at least two not working when you flick the switch.
In the bathroom I have 2 over the wash basin. One is fine, rock solid,
the other comes on if it feels like it.
Can anyone explain why this is to me?

I'll assume 12v, as these seem to give most trouble....

Lampholders is always first place to look , they run very hot indeed,
misalignment of lamp pins, arcing on the pins or thermal expansion
can often lead to problems.

12V MR16 is only troublesome with things like misaligned lamps in
their holders, if you spend more than a packet of 10 cigarettes on the
trafos they tend to be very reliable.
GU10 , so often changing lamps that age related problems never have
time to surface ;-)

Adam


At 12v the current is close to 2amps and the contacts of the lamps
socket can overheat and become poor/intermitant. Nudging the lamps in
the holders often overcomes the poor contact for the duration that they
are still turned on, but as they cool the contact goes bad again. In
which case replace the sockets and affected lamps with new.

2nd possibility...

If the filament burns out, you can often tap the lamp and get the
filament to make contact again for the time they remain on, the fix is
new lamps.

3rd possibility...

If the 240 to 12v transformers (SMPSU) see no load at switch on, they
can shut themselves down. This might apply to both of the above
scenarios.

--
Regards,
* * * * Harry (M1BYT) (L)http://www.ukradioamateur.co.uk

On 14 Feb, 06:29, Mikeyboy wrote:
They are so on and off! I bought a ceiling light for my daughter's
bedroom with around 6 halogen (20w) in it. When you switch it on, you
are lucky if 4 of them come on. If you fiddle with the rest they
usually come on eventually, but once switched off, you are back to the
same scenario with at least two not working when you flick the switch.
In the bathroom I have 2 over the wash basin. One is fine, rock solid,
the other comes on if it feels like it.
Can anyone explain why this is to me?
is there an answer?
Sooooooo tedious. I think I'll go back to a single 150 w bulb till
they are impossible to find.

Consider not using Halogen all together. They have a short lifespan
and use too much energy. LED lights can work as a straight replacement
using 1/9 the power. Compact Fluorescent Lights exist the the same
size using 1/5 the power.
References:
http://www.matthewb.id.au/index.php?...ntent&Itemid=8
http://www.matthewb.id.au/media/Ligh...alculator.html

In article
,
matthewb wrote:
Consider not using Halogen all together. They have a short lifespan
and use too much energy. LED lights can work as a straight replacement
using 1/9 the power. Compact Fluorescent Lights exist the the same
size using 1/5 the power.
References:

Referring to your own websites for 'proof' is rather pointless?

BTW, they miss out the most important thing to many - light quality.

--
*The average person falls asleep in seven minutes *

Dave Plowman London SW
To e-mail, change noise into sound.

On 16 Feb, 01:38, matthewb wrote:
On 14 Feb, 06:29, Mikeyboy wrote:

They are so on and off! I bought a ceiling light for my daughter's
bedroom with around 6 halogen (20w) in it. When you switch it on, you
are lucky if 4 of them come on. If you fiddle with the rest they
usually come on eventually, but once switched off, you are back to the
same scenario with at least two not working when you flick the switch.
In the bathroom I have 2 over the wash basin. One is fine, rock solid,
the other comes on if it feels like it.
Can anyone explain why this is to me?
is there an answer?
Sooooooo tedious. I think I'll go back to a single 150 w bulb till
they are impossible to find.

Consider not using Halogen all together. They have a short lifespan
and use too much energy. LED lights can work as a straight replacement
using 1/9 the power. Compact Fluorescent Lights exist the the same
size using 1/5 the power.
References:http://www.matthewb.id.au/index.php?...alculator.html

Added sci.engr.lighting as crosspost

Matthew creditable and nicely presented web site and calculator but
like your above figures , missing a vital piece of information, actual
useable light output.

"LED lights can work as a straight replacement using 1/9 the power."

Unfortunately not even close, LED is currently almost never a
`straight replacement` for halogen lamps, there getting better on an
almost weekly basis but having worked with LED sources for more than
10 years, they still are not a straight drop in replacement for a 50W
12V MR16 or even a GU10 MR16.

LEDs used in the right way , with an understanding of their advantages
and limitations are great and offer possibilities not possible with
any other light source.

What they don`t offer is a universal drop in replacement fo all other
forms of lighting, have to deal with people who have been oversold LED
lighting , at not inconsiderable expense, that dosen`t do what they
were sold on it would do.

"Compact Fluorescent Lights exist the the same size using 1/5 the
power."

Closer but again missing out quantity of light delivered on task,
original poster has problems with MR16, 50mm diameter, reflector
lamps. Compact fuorescent, some of them are actually compact cold
cathode which isnt as efficient as compact fluro, lamps in this style
have awful real world efficiency, the lamp is folded so much to fit in
the space that it obscures a large amount of its own output, they
really aren`t very good.

Lies , damned lies and statistics is still as true as it ever was.

Adam

In ,
Adam Aglionby wrote:

On 16 Feb, 01:38, matthewb wrote:
On 14 Feb, 06:29, Mikeyboy wrote:

They are so on and off! I bought a ceiling light for my daughter's
bedroom with around 6 halogen (20w) in it. When you switch it on, you
are lucky if 4 of them come on. If you fiddle with the rest they
usually come on eventually, but once switched off, you are back to the
same scenario with at least two not working when you flick the switch.
In the bathroom I have 2 over the wash basin. One is fine, rock solid,
the other comes on if it feels like it.
Can anyone explain why this is to me?
is there an answer?
Sooooooo tedious. I think I'll go back to a single 150 w bulb till
they are impossible to find.

Consider not using Halogen all together. They have a short lifespan
and use too much energy. LED lights can work as a straight replacement
using 1/9 the power. Compact Fluorescent Lights exist the the same
size using 1/5 the power.
References:http://www.matthewb.id.au/index.php?...ticle&catid=6:
energy-effic...http://www.matthewb.id.au/media/Ligh...alculator.html

Added sci.engr.lighting as crosspost

Matthew creditable and nicely presented web site and calculator but
like your above figures , missing a vital piece of information, actual
useable light output.

"LED lights can work as a straight replacement using 1/9 the power."

Unfortunately not even close, LED is currently almost never a
`straight replacement` for halogen lamps, there getting better on an
almost weekly basis but having worked with LED sources for more than
10 years, they still are not a straight drop in replacement for a 50W
12V MR16 or even a GU10 MR16.

LEDs used in the right way , with an understanding of their advantages
and limitations are great and offer possibilities not possible with
any other light source.

What they don`t offer is a universal drop in replacement fo all other
forms of lighting, have to deal with people who have been oversold LED
lighting , at not inconsiderable expense, that dosen`t do what they
were sold on it would do.

Also, LEDs 9 times as efficient as halogen lamps sounds like a tall
claim to me. Halogen lamps used for lighting mostly achieve 15-21
lumens/watt. 9 times 15 is 135, and I have yet to hear of an LED on the
market that efficient, except for extreme of high end white ones when they
are seriously underpowered (like 50 mA for ones with 1 mm square ballpark
chips, rated 350-1500 mA). 80-100 lumens/watt sounds to me high side high
end for LED lighting products. Last time I checked out results of
D.O.E.'s "Caliper" program (November 2008 or so), high end was 60's
lumens/watt and few products got past the 40's.

"Compact Fluorescent Lights exist the the same size using 1/5 the power."

Most CFLs achieve close to 60 lumens/watt. Highest I have heard for one
consuming less than 45 watts (including ballast losses) is 70 lumens/watt
for Philips 25 watt "triple arch" SLS model.

Closer but again missing out quantity of light delivered on task,
original poster has problems with MR16, 50mm diameter, reflector
lamps. Compact fuorescent, some of them are actually compact cold
cathode which isnt as efficient as compact fluro, lamps in this style
have awful real world efficiency, the lamp is folded so much to fit in
the space that it obscures a large amount of its own output, they
really aren`t very good.

CFLs in reflectors also have wider beam spread and often lower
percentage of light within the beam than incandescent/halogen reflector
lamps have. The larger light source size makes the light harder to
control unless a similarly larger reflector/optic is used.

Lies, damned lies and statistics is still as true as it ever was.

Adam

I agree and maybe a little and-then-some!

CFLs and most white LEDs are more efficient than incandescents and
halogens, but exaggerated and/or excessively-optimistic claims of degree
of improvement appear to me to be common. Such excessively optimistic
and/or exaggerated claims lead to disappointment, and to skepticism and
distrust of new lightuing technologies, especially if marketed or
manufactured by anyone not having had a solid reputation in lighting for
at least something like a decade or two.

- Don Klipstein )

Dave Plowman (News) wrote:
In article
,
matthewb wrote:
Consider not using Halogen all together. They have a short lifespan
and use too much energy. LED lights can work as a straight replacement
using 1/9 the power. Compact Fluorescent Lights exist the the same
size using 1/5 the power.
References:

Referring to your own websites for 'proof' is rather pointless?

BTW, they miss out the most important thing to many - light quality.

My LV halogens outlast the CFL's here.

On Mon, 16 Feb 2009 07:12:24 -0800 (PST), Adam Aglionby
wrote:

[snip]

Unfortunately not even close, LED is currently almost never a
`straight replacement` for halogen lamps, there getting better on an
almost weekly basis but having worked with LED sources for more than
10 years, they still are not a straight drop in replacement for a 50W
12V MR16 or even a GU10 MR16.

Adam,

One reason why there are no "real" drop-in replacements for
50-watt MR16 lamps is that the MR16 form factor does not
provide enough heat sink area for any current-generation LED
that creates as much light as a 12-volt, 50-watt halogen
lamp.

There are LED-based MR16 lamps that replace 20-watt halogen
MR16's because they have lower power dissipation
requirements. These are indeed more efficient than the
equivalent halogen, but certainly not by nine times! About
twice last time I checked.


--
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.

On 17 Feb, 13:50, Victor Roberts wrote:
On Mon, 16 Feb 2009 07:12:24 -0800 (PST), Adam Aglionby

wrote:

[snip]



Unfortunately not even close, LED is currently almost never a
`straight replacement` for halogen lamps, there getting better on an
almost weekly basis but having worked with LED sources for more than
10 years, they still are not a straight drop in replacement for a 50W
12V MR16 or even a GU10 MR16.

Adam,

One reason why there are no "real" drop-in replacements for
50-watt MR16 lamps is that the MR16 form factor does not
provide enough heat sink area for any current-generation LED
that creates as much light as a 12-volt, 50-watt halogen
lamp.

There are LED-based MR16 lamps that replace 20-watt halogen
MR16's because they have lower power dissipation
requirements. *These are indeed more efficient than the
equivalent halogen, but certainly not by nine times! * About
twice last time I checked.

--
Vic Robertshttp://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.

Same problem with bigger lights, lot of cheap LED PAR 56/64 cans,type
of stage light for uninitiated, use the 56/64 shells because it is a
convenient low cost housing for what is really a completely different
type of light, light output from a 30W LED PAR64 really isnt the same
as 1KW tungsten one ;-)

MR16 is big target for all sorts of retrofit hokum,CFL GU10s being
prime example, LEDs not being immune, but there are some great MR16
format LED lamps just not realistic to market them as `drop in
replacements`.

Going down to MR8 LED actually makes a lot of sense, halogen MR8s look
pretty but aren`t very efficient, format fits single big LED and
heatsink very well though.

People get sold on lighting being completely retrofittable even with
the most inappropriate original schemes, sometimes its kindest to tell
clients that proper refurbishment is what they need, not a pile of
dubious `drop in replacements`

Adam

On Feb 19, 12:32*pm, Adam Aglionby wrote:
On 17 Feb, 13:50, Victor Roberts wrote:





On Mon, 16 Feb 2009 07:12:24 -0800 (PST), Adam Aglionby

wrote:

[snip]

Unfortunately not even close, LED is currently almost never a
`straight replacement` for halogen lamps, there getting better on an
almost weekly basis but having worked with LED sources for more than
10 years, they still are not a straight drop in replacement for a 50W
12V MR16 or even a GU10 MR16.

Adam,

One reason why there are no "real" drop-in replacements for
50-watt MR16 lamps is that the MR16 form factor does not
provide enough heat sink area for any current-generation LED
that creates as much light as a 12-volt, 50-watt halogen
lamp.

There are LED-based MR16 lamps that replace 20-watt halogen
MR16's because they have lower power dissipation
requirements. *These are indeed more efficient than the
equivalent halogen, but certainly not by nine times! * About
twice last time I checked.

--
Vic Robertshttp://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.

Same problem with bigger lights, lot of cheap LED PAR 56/64 cans,type
of stage light for uninitiated, *use the 56/64 shells because it is a
convenient low cost housing for what is really a completely different
type of light, *light output from a 30W LED PAR64 really isnt the same
as 1KW tungsten one ;-)

MR16 is big target for all sorts of retrofit hokum,CFL GU10s being
prime example, LEDs not being immune, but there are some great MR16
format LED lamps just not realistic to market them as `drop in
replacements`.

Going down to MR8 LED actually makes a lot of sense, halogen MR8s look
pretty but aren`t very efficient, format fits single big LED and
heatsink very well though.

People get sold on lighting being completely retrofittable even with
the most inappropriate original schemes, sometimes its kindest to tell
clients that proper refurbishment is what they need, not a pile of
dubious *`drop in replacements`

Adam- Hide quoted text -

- Show quoted text -

Now that you brought up stage lighting:

There is another angle to get folks confused. Stage lights are
intended to be used with filters. Some of the deepest colors run about
5% transmition, and many of the paler shades are only 70%.

I'm now seeing marketing claims based on the filtered output of PARs.
*IF* all you want to use is the narrow range of deep blues,. greens
and reds then LEDs are perfect.

(Side issue ETC a major theatrical lighting company just bought
Selador, an LED fixture maker that specializes in useing 7 colors of
LEDs to widen the pallet. If you're in theater this is major news.)

---
RickR