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When they are RUN at the rated voltage and power. If you dim them the
tungsten is deposited on the quartz and short of heating the quarts to
white hot (above poster's remarks) the tungsten is going to STAY on the
quartz, not recoating on the filament.
http://www.topbulb.com/blog/dimming-alters-halogen-cycle/
** That is merely one person's opinion, not backed up with evidence.
Wiki says differently :
https://en.wikipedia.org/wiki/Halogen_lamp#Effect_of_voltage_on_performance
Stage lighting uses dimming all the time with halogen lamps and there is
no blackening or short life experienced - the lamps run much longer as
expected.
The claim that the "halogen cycle" puts metal back on the filament is true
but it does not deposit it back where it came from so has little effect on
lamp life.
Most halogen lamps are low voltage or high powered - so in both cases the
filaments are thicker than typical non halogen examples.
Wrong ....
That may be your belief. IRL halogen stage lighting works just fine.
It wouldn't be any surprise .
Ian Fuckwit Field wrote:
------------------------------
That may be your belief. IRL halogen stage lighting works just fine.
It wouldn't be any surprise .
** Any fact whatever would be HUGE surprise to a fuckwit like you.
if stage lighting is over run for short periods
** Errr - dimmers only dim lamps down, not up.
It is often assumed that incandescent and halogen light bulbs are completely different technologies. In fact, halogen is just a hybrid incandescent.
Both types of light bulbs use a tungsten filament. Both âburn outâ when the filament breaks. Both use line and low voltage the same way.
Also, both incandescent and halogen bulbs can be dimmed. But hereâs the interesting twist: the more a halogen bulb is dimmed, the more it becomes an incandescent light bulb again.
How Incandescent and Halogen Differ
The standard incandescent bulb is filled with a mixture of argon gas and a small amount of nitrogen gas. Inside this gas mix, the tungsten filament, heated to âincandescenceâ, slowly evaporates. Thinner portions of the filament get hotter and they evaporate more quickly. The evaporated tungsten deposits on the inside wall of the glass. Eventually, the filament evaporates so much tungsten that it breaks or âburns outâ.
A halogen bulb mimics the technology of incandescent except for two features. First, the filament and gas are contained in a quartz capsule resistant to high temperature. Second, a halogen gas such as bromine or iodine is added to the gas mix. With this gas mixture and higher filament temperatures, a chemical change occurs to the tungsten filament evaporation process. Instead of depositing the evaporated tungsten on the bulb glass, it is deposited instead back onto the filament itself. This process of filament regeneration is known as the halogen cycle. It can double the life of an incandescent bulb.
In short the primary difference between halogen and incandescent is the existence of the halogen cycle operating in a quartz capsule.
Dimming Halogen Lights and Bulb Life
That brings us back to dimming.
Dimming works the same way for both incandescent and halogen. Lower the filament temperature by modifying the voltage and get progressively less light output. The halogen cycle works only at high filament temperatures. If the halogen bulb is dimmed enough (down to only 20% less light), the filament temperature drops and the halogen cycle stops. At that point, it is operating in âincandescent modeâ with evaporated tungsten being deposited on the capsule wall rather than back on the filament.
Tip: While dimming often lengthens the life of incandescent bulbs, it may shorten the life of halogen bulbs and cause darkening of the quartz capsule.
Thanks to: David Burtner
http://www.topbulb.com/blog/dimming-alters-halogen-cycle/
Key Points:
a) Halogen lamps are hybrid incandescent lamps. We knew that.
b) The "Halogen Cycle" redeposits tungsten on the filament as compared to a standard incandescent lamp that gradually evaporates the tungsten.
c) The halogen cycle stops at around 20% LESS LIGHT. That would be at/around 80% of full light. Whereupon the lamp behaves as a standard incandescent lamp.
d) With all this in mind, a halogen lamp may be dimmed with the same technology, means and methods as a standard incandescent lamp. Primary effects are on life-span. The failure modes are unchanged, eventually the filament fails.
It ain't nohow rocket science.
Anyone with even a passing experience with lighting already knows all this -as well as even the lowliest sweeper at any given electrical supply house.
Peter Wieck
Melrose Park, PA
Since dimming is usually done at assorted levels, the above effect has sod all effect on lamp life in the real world in most cases.
It is often assumed that incandescent and halogen light bulbs are completely different technologies. In fact, halogen is just a hybrid incandescent.
Both types of light bulbs use a tungsten filament. Both âburn outâ when the filament breaks. Both use line and low voltage the same way.
Also, both incandescent and halogen bulbs can be dimmed. But hereâs the interesting twist: the more a halogen bulb is dimmed, the more it becomes an incandescent light bulb again.
How Incandescent and Halogen Differ
The standard incandescent bulb is filled with a mixture of argon gas and a small amount of nitrogen gas. Inside this gas mix, the tungsten filament, heated to âincandescenceâ, slowly evaporates. Thinner portions of the filament get hotter and they evaporate more quickly. The evaporated tungsten deposits on the inside wall of the glass. Eventually, the filament evaporates so much tungsten that it breaks or âburns outâ.
A halogen bulb mimics the technology of incandescent except for two features. First, the filament and gas are contained in a quartz capsule resistant to high temperature. Second, a halogen gas such as bromine or iodine is added to the gas mix. With this gas mixture and higher filament temperatures, a chemical change occurs to the tungsten filament evaporation process. Instead of depositing the evaporated tungsten on the bulb glass, it is deposited instead back onto the filament itself. This process of filament regeneration is known as the halogen cycle. It can double the life of an incandescent bulb.
In short the primary difference between halogen and incandescent is the existence of the halogen cycle operating in a quartz capsule.
Dimming Halogen Lights and Bulb Life
That brings us back to dimming.
Dimming works the same way for both incandescent and halogen. Lower the filament temperature by modifying the voltage and get progressively less light output. The halogen cycle works only at high filament temperatures. If the halogen bulb is dimmed enough (down to only 20% less light), the filament temperature drops and the halogen cycle stops. At that point, it is operating in âincandescent modeâ with evaporated tungsten being deposited on the capsule wall rather than back on the filament.
Tip: While dimming often lengthens the life of incandescent bulbs, it may shorten the life of halogen bulbs and cause darkening of the quartz capsule.
Thanks to: David Burtner
http://www.topbulb.com/blog/dimming-alters-halogen-cycle/
Key Points:
a) Halogen lamps are hybrid incandescent lamps. We knew that.
b) The "Halogen Cycle" redeposits tungsten on the filament as compared to a standard incandescent lamp that gradually evaporates the tungsten.
c) The halogen cycle stops at around 20% LESS LIGHT. That would be at/around 80% of full light. Whereupon the lamp behaves as a standard incandescent lamp.
d) With all this in mind, a halogen lamp may be dimmed with the same technology, means and methods as a standard incandescent lamp. Primary effects are on life-span. The failure modes are unchanged, eventually the filament fails.
It ain't nohow rocket science.
Anyone with even a passing experience with lighting already knows all this -as well as even the lowliest sweeper at any given electrical supply house.
Peter Wieck
Melrose Park, PA
On Wednesday, June 28, 2017 at 4:58:08 PM UTC-4, tabby wrote:
Since dimming is usually done at assorted levels, the above effect has sod all effect on lamp life in the real world in most cases.
Suffice it that if a halogen lamp operates at <80% of nominal voltage, the
That may be your belief. IRL halogen stage lighting works just fine.
It wouldn't be any surprise .
** Any fact whatever would be HUGE surprise to a fuckwit like you.
if stage lighting is over run for short periods
** Errr - dimmers only dim lamps down, not up.
They don't get any dimmer than you - some stage lighting used variacs that
went up to 110%.
Thanks to: David Burtner
http://www.topbulb.com/blog/dimming-alters-halogen-cycle/
It ain't nohow rocket science.
Anyone with even a passing experience with lighting already knows all this -as well as even the lowliest sweeper at any given electrical supply house.
John Robertson wrote:
----------------------
When they are RUN at the rated voltage and power. If you dim them the
tungsten is deposited on the quartz and short of heating the quarts to
white hot (above poster's remarks) the tungsten is going to STAY on the
quartz, not recoating on the filament.
http://www.topbulb.com/blog/dimming-alters-halogen-cycle/
** That is merely one person's opinion, not backed up with evidence.
Wiki says differently :
https://en.wikipedia.org/wiki/Halogen_lamp#Effect_of_voltage_on_performance
Stage lighting uses dimming all the time with halogen lamps and there is no blackening or short life experienced - the lamps run much longer as expected.
The claim that the "halogen cycle" puts metal back on the filament is true but it does not deposit it back where it came from so has little effect on lamp life.
Most halogen lamps are low voltage or high powered - so in both cases the filaments are thicker than typical non halogen examples.
Having a thick filament makes a halogen lamp last longer.
..... Phil
One more thing: if you look at a halogen lamp crosseyed the filament will
fail from the shock of your stare.. The filaments are not supported as
they are in a standard incandescent lamp so they must not be subject to
shock or vibration.
Ian Field wrote:
That may be your belief. IRL halogen stage lighting works just fine.
snip
They don't get any dimmer than you - some stage lighting used variacs that
went up to 110%.
** Long in the past when there were no halogen lamps involved.
Well, I must confess I've never studied halogen bulbs on dimmers but
reading Lutron's site does not give any concerns from them about
halogens on dimmers in household use:
http://www.lutron.com/en-US/Education-Training/Pages/LCE/DimmingBasics.aspx
I would like to assume that you are correct, Phil. One problem though -
your reference source says:
"With a reduced voltage the evaporation is lower and there may be too
much halogen, which can lead to abnormal failure."
and also:
"There are many situations where halogen lamps are dimmed successfully.
However, lamp life may not be extended as much as predicted. The life
span on dimming depends on lamp construction, the halogen additive used
and whether dimming is normally expected for this type."
So, perhaps theatre halogen bulbs are designed to be dimmed?
http://stagelightingprimer.com/slfs-light_sources.html
Perhaps not, they don't mind of the bulb lasts a shorter time, but want
the brightness in a compact source.
Also, are house halogen bulbs designed to be dimmed?
Philips bulbs seem to be (perhaps...):
http://www.philips.ca/c-m-li/halogen-light-bulbs
"Halogen lamps are designed to operate at very high temperatures to
ensure optimal performance. Dimming at above 60% of the rated volts can
be done. It is recommended to revert to full brightness for one minute
prior to switching the lamps off."
In other words do not run them above 60% of rated line voltage for
extended times without heating/running them at 100% for one minute prior
to turning off. I am SURE everyone will do that!
A double blind test would be nice to put this to bed.
John :-#)#
John-Delusional wrote:
One more thing: if you look at a halogen lamp crosseyed the filament will
fail from the shock of your stare.. The filaments are not supported as
they are in a standard incandescent lamp so they must not be subject to
shock or vibration.
** See pics of 150W halogen tube lamps:
http://www.destinationlighting.com/images/products_zoom/549/13549~zoom.jpg
http://www.homedepot.com/catalog/productImages/1000/b7/b7e4d552-8a07-4441-a54c-0c250efeef67_1000.jpg
https://images.musicstore.de/images/1600/omnilux-halogen-lamp-bulb-g-6-35-150-watts-24-volts_1_LIG0000456-000.jpg
How about a 1000W one:
http://ecx.images-amazon.com/images/I/6174-2HVwIL._SL1500_.jpg
.... Phil
So, perhaps theatre halogen bulbs are designed to be dimmed?
"Halogen lamps are designed to operate at very high temperatures to
ensure optimal performance. Dimming at above 60% of the rated volts can
be done. It is recommended to revert to full brightness for one minute
prior to switching the lamps off."
In other words do not run them above 60% of rated line voltage for
extended times without heating/running them at 100% for one minute prior
to turning off. I am SURE everyone will do that!
You fuckwit, lying POS.
no, just short on knowledge.
tabby wrote:
You fuckwit, lying POS.
no, just short on knowledge.
** Ian Field is a prize fuckwit, a congenital liar and a POS.
He makes facts up and uses false logic constantly.
He is clearly an autistic dim wit.
Just like thousands of other internet trolls.
John-Delusional wrote:
---------------------------
One more thing: if you look at a halogen lamp crosseyed the filament will
fail from the shock of your stare.. The filaments are not supported as
they are in a standard incandescent lamp so they must not be subject to
shock or vibration.
** See pics of 150W halogen tube lamps:
http://www.destinationlighting.com/images/products_zoom/549/13549~zoom.jpg
http://www.homedepot.com/catalog/productImages/1000/b7/b7e4d552-8a07-4441-a54c-0c250efeef67_1000.jpg
https://images.musicstore.de/images/1600/omnilux-halogen-lamp-bulb-g-6-35-150-watts-24-volts_1_LIG0000456-000.jpg
How about a 1000W one:
http://ecx.images-amazon.com/images/I/6174-2HVwIL._SL1500_.jpg
.... Phil