picked up a 250W MH lamp...

[Andrew Gabriel]

Noticed a 250W MH lamp in a local junk shop some time ago.
Can't recall the price, but it was too expensive to buy just
for the curiosity value. Yesterday, it was reduced to £10
which fell into the "lets get it on the off-chance it might
be useful one day" range. Was hoping it would be a nice
warm white colour, but on powering it up, everything turned
bluish. The lamp label is quite faded, but I can just make
out that it's an Aqualite 10,000K lamp, i.e. about as far
from warm white as you can get. ;-) A web search reveals
this is used for aquarium and corals lighting. There's no
manufacturer's name on the luminare or control gear box.

The lamp generates a strong ozone smell, but I think this
is all coming from inside the luminare -- it has a glass
cover which should stop the UV getting out.

This has got me thinking about a project I mentioned a few
weeks back -- converting a torcherie to use a 70W MH lamp.
If that were to generate even a quarter of the ozone smell
this 250W lamp does, it would not be viable in a living room.
Is that likely?

 

[Victor Roberts]

Noticed a 250W MH lamp in a local junk shop some time ago.
Can't recall the price, but it was too expensive to buy just
for the curiosity value. Yesterday, it was reduced to £10
which fell into the "lets get it on the off-chance it might
be useful one day" range. Was hoping it would be a nice
warm white colour, but on powering it up, everything turned
bluish. The lamp label is quite faded, but I can just make
out that it's an Aqualite 10,000K lamp, i.e. about as far
from warm white as you can get. ;-) A web search reveals
this is used for aquarium and corals lighting. There's no
manufacturer's name on the luminare or control gear box.

The lamp generates a strong ozone smell, but I think this
is all coming from inside the luminare -- it has a glass
cover which should stop the UV getting out.

This has got me thinking about a project I mentioned a few
weeks back -- converting a torcherie to use a 70W MH lamp.
If that were to generate even a quarter of the ozone smell
this 250W lamp does, it would not be viable in a living room.
Is that likely?

Normal metal halide lamps should not generate any
significant amount of ozone. I used a 250-watt or 400-watt
metal halide lamp in my lab at the GE R&D Center and there
was no ozone smell at all. Large numbers of metal halide
lamps are used to light interior spaces such as large food
stores and "big box" retail stores and I have also not
detected any ozone smell in those stores either.

Aqualite is a Ushio trademark and you can find SPD curves
for the various versions of the Aqualite at
http://www.ushio.com/Files/Aqualite.pdf. These lamps
generate considerably more UV than metal halide lamps
designed for general lighting. Note that the data sheet says
that people should not be directly exposed to the light from
this lamp without a UV unless a UV absorbing glass is used
as a filter. I would therefore not extrapolate the ozone
production characteristics of these lamps to the 250-watt
lamp you might use in your torchiere - unless, of course,
you plan to use a 10,000K lamp in the torchiere

--
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.

 

[SQLit]

Noticed a 250W MH lamp in a local junk shop some time ago.
Can't recall the price, but it was too expensive to buy just
for the curiosity value. Yesterday, it was reduced to £10
which fell into the "lets get it on the off-chance it might
be useful one day" range. Was hoping it would be a nice
warm white colour, but on powering it up, everything turned
bluish. The lamp label is quite faded, but I can just make
out that it's an Aqualite 10,000K lamp, i.e. about as far
from warm white as you can get. ;-) A web search reveals
this is used for aquarium and corals lighting. There's no
manufacturer's name on the luminare or control gear box.

The lamp generates a strong ozone smell, but I think this
is all coming from inside the luminare -- it has a glass
cover which should stop the UV getting out.

This has got me thinking about a project I mentioned a few
weeks back -- converting a torcherie to use a 70W MH lamp.
If that were to generate even a quarter of the ozone smell
this 250W lamp does, it would not be viable in a living room.
Is that likely?

Check if the outer bulb is cracked anywhere. [*] As far as I know this type
of metal halide should not generate any ozone. Sounds equivalent to the
OSRAM/Radium "Blau" metal halide, used as you say for aquarium lighting.
These radiate predominantly at the Indium lines on the blue.

Lucky guy. I've been hunting one of those down for years, to try to add its
spectrum to my spectra page

[*] I've gotten some halides before, which were really hard to detect for
cracks. On one the crack was exactly at the evacuation bubble, near the
metal base of the lamp.--

If the outer shell is cracked, the lamp is well on the way to being a
grenade. Usually MH lamps are enclosed because of this.

There are color corrected MH lamps available. To a point. They are not
cheap nor available at the local store

 

[Clive Mitchell]

This has got me thinking about a project I mentioned a few weeks back
-- converting a torcherie to use a 70W MH lamp. If that were to
generate even a quarter of the ozone smell this 250W lamp does, it
would not be viable in a living room. Is that likely?

Most modern metal halide lamps are designed to limit the amount of
harmful UV emitted and ozone generated.

 

[Andrew Gabriel]

Check if the outer bulb is cracked anywhere.

No it's not, although I can't see how that would cause ozone
unless there was also some glass missing from it. I had to
tug sufficiently hard on it to get it out of the lampholders
that I suspect it would have shattered if it was cracked or
weakened anywhere.

of metal halide should not generate any ozone. Sounds equivalent to the
OSRAM/Radium "Blau" metal halide, used as you say for aquarium lighting.
These radiate predominantly at the Indium lines on the blue.

Lucky guy. I've been hunting one of those down for years, to try to add its
spectrum to my spectra page

They look to be significantly more expensive than regular
MH lamps too.

 

[TKM]

Noticed a 250W MH lamp in a local junk shop some time ago.
Can't recall the price, but it was too expensive to buy just
for the curiosity value. Yesterday, it was reduced to £10
which fell into the "lets get it on the off-chance it might
be useful one day" range. Was hoping it would be a nice
warm white colour, but on powering it up, everything turned
bluish. The lamp label is quite faded, but I can just make
out that it's an Aqualite 10,000K lamp, i.e. about as far
from warm white as you can get. ;-) A web search reveals
this is used for aquarium and corals lighting. There's no
manufacturer's name on the luminare or control gear box.

The lamp generates a strong ozone smell, but I think this
is all coming from inside the luminare -- it has a glass
cover which should stop the UV getting out.

This has got me thinking about a project I mentioned a few
weeks back -- converting a torcherie to use a 70W MH lamp.
If that were to generate even a quarter of the ozone smell
this 250W lamp does, it would not be viable in a living room.
Is that likely?

Yes, there is something wrong with the lamp or the electrics. General
lighting metal halide lamps don't generate any ozone to speak of and
certainly not enough for normal folks to smell.

This lamp is not intended for general lighting according to the
manufacturer's web site because of the high UV output. At the very least,
it should be mounted inside a metal/glass enclosure to eliminate the UV and
protect against possible arc tube rupture.

My choice for torchieres or any interior general lighting where aesthetics
count is the ceramic metal halide (CMH). Georgeous light and color plus
they are available in several wattages.

Terry McGowan