Discussion:
Fluorescent tubes mounted vertically
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TimR
2012-02-19 03:22:17 UTC
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I found this note on the Osram site:

In cases in which the lamps or luminaires are arranged vertically or
at an angle, the lamps must be fitted so that the end with the type
designation (stamp) is located at the bottom (coldest necessary
position for optimum luminous flux at the bottom). With FC the
circular T 5 and vertical arrangement, the lamp cap is to be located
at the bottom.


Why would this be so? In general, will any fluorescent fixture work
mounted vertically? The application I'm thinking of is to mount one
on the wall behind a tall plant.
Andrew Gabriel
2012-02-19 09:35:16 UTC
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Post by TimR
In cases in which the lamps or luminaires are arranged vertically or
at an angle, the lamps must be fitted so that the end with the type
designation (stamp) is located at the bottom (coldest necessary
position for optimum luminous flux at the bottom). With FC the
circular T 5 and vertical arrangement, the lamp cap is to be located
at the bottom.
Why would this be so?
To prevent the cold spot (which is at the end with the tube markings)
from being heated by convection. The cold spot is some extra space
behind the filament which is at one end only, and the temperature of
the coldest part of the tube is key for setting the mercury vapor
pressure in the whole tube.

AFAIK, this applies only to T5 tubes.
Post by TimR
In general, will any fluorescent fixture work
mounted vertically?
Yes.
Post by TimR
The application I'm thinking of is to mount one
on the wall behind a tall plant.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
Jeff Waymouth
2012-02-19 13:54:59 UTC
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T5 technology employs a "cold spot" design which helps to maintain
proper mercury vapor pressure while operating. This is done by mounting
one electrode deeper within the lamp than the opposite one.
In OSRAM and OSRAM SYLVANIA products, the lamp etch (lable, designation)
is used to indicate the end with the deeper insertion.

While this end is down, convection currents within the lamp keep that
end at its proper temperature where it would overheat if it were
installed etch end up.


Jeff Waymouth
Post by TimR
In cases in which the lamps or luminaires are arranged vertically or
at an angle, the lamps must be fitted so that the end with the type
designation (stamp) is located at the bottom (coldest necessary
position for optimum luminous flux at the bottom). With FC the
circular T 5 and vertical arrangement, the lamp cap is to be located
at the bottom.
Why would this be so? In general, will any fluorescent fixture work
mounted vertically? The application I'm thinking of is to mount one
on the wall behind a tall plant.
John Gorce
2012-02-19 17:38:41 UTC
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Post by Jeff Waymouth
T5 technology employs a "cold spot" design which helps to maintain
proper mercury vapor pressure while operating. This is done by
mounting one electrode deeper within the lamp than the opposite one.
In OSRAM and OSRAM SYLVANIA products, the lamp etch (lable,
designation) is used to indicate the end with the deeper insertion.
While this end is down, convection currents within the lamp keep that
end at its proper temperature where it would overheat if it were
installed etch end up.
Jeff,

do you or anyone else know what a golden strip attached along the length of the
tube would be for?

The lamp is PHILIPS: TL AK 40W/03
V: 47
A: 0.880
Cap: G13
d: 38mm
L: 61 cm

The golden strip starts at one end cap, and ends at the opposite cap and runs
along the length of the entire tube. It looks like its attached/etched on the
glass.

Something to do with burning position maybe?

I've been wondering about this for some 20+ years now. I don't have the lamp
anymore, so thought maybe someone here knows what it's for.

The lamp's electrical characteristics seem to be identical to a regular linear
40W fluoro, but I don't know anything about the burning position because when I
got it one of the electrodes was cut, so I had to jump-start it by shorting it
directly.

Many thanks,
Post by Jeff Waymouth
Jeff Waymouth
Post by TimR
In cases in which the lamps or luminaires are arranged vertically or
at an angle, the lamps must be fitted so that the end with the type
designation (stamp) is located at the bottom (coldest necessary
position for optimum luminous flux at the bottom). With FC the
circular T 5 and vertical arrangement, the lamp cap is to be located
at the bottom.
Why would this be so? In general, will any fluorescent fixture work
mounted vertically? The application I'm thinking of is to mount one
on the wall behind a tall plant.
--
I.
TimR
2012-02-19 23:14:49 UTC
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Thanks, I didn't know about cold spots.
Tomsic
2012-02-20 15:49:26 UTC
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Regarding, the "golden strip" running the length of the lamp -- I'm not
familiar with the Phllips lamp itself, but such strips have been used as
starting aids for lamps on rapid-start circuits in the past. The strip
makes it easier for the lamp to ionize with the available ballast starting
voltage.

Starting strips also allow a fluorescent lamp to be used with certain
ballasts in luminaires made of non-conductive materials since normally with
such ballasts the starting-strip function is provided by the metal of the
luminaire.

Terry McGowan
Post by John Gorce
Post by Jeff Waymouth
T5 technology employs a "cold spot" design which helps to maintain
proper mercury vapor pressure while operating. This is done by
mounting one electrode deeper within the lamp than the opposite one.
In OSRAM and OSRAM SYLVANIA products, the lamp etch (lable,
designation) is used to indicate the end with the deeper insertion.
While this end is down, convection currents within the lamp keep that
end at its proper temperature where it would overheat if it were
installed etch end up.
Jeff,
do you or anyone else know what a golden strip attached along the length
of the tube would be for?
The lamp is PHILIPS: TL AK 40W/03
V: 47
A: 0.880
Cap: G13
d: 38mm
L: 61 cm
The golden strip starts at one end cap, and ends at the opposite cap and
runs along the length of the entire tube. It looks like its
attached/etched on the glass.
Something to do with burning position maybe?
I've been wondering about this for some 20+ years now. I don't have the
lamp anymore, so thought maybe someone here knows what it's for.
The lamp's electrical characteristics seem to be identical to a regular
linear 40W fluoro, but I don't know anything about the burning position
because when I got it one of the electrodes was cut, so I had to
jump-start it by shorting it directly.
Many thanks,
Post by Jeff Waymouth
Jeff Waymouth
Post by TimR
In cases in which the lamps or luminaires are arranged vertically or
at an angle, the lamps must be fitted so that the end with the type
designation (stamp) is located at the bottom (coldest necessary
position for optimum luminous flux at the bottom). With FC the
circular T 5 and vertical arrangement, the lamp cap is to be located
at the bottom.
Why would this be so? In general, will any fluorescent fixture work
mounted vertically? The application I'm thinking of is to mount one
on the wall behind a tall plant.
--
I.
I.N. Galidakis
2012-02-20 16:36:06 UTC
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Thanks Terry.
--
I.
Post by Tomsic
Regarding, the "golden strip" running the length of the lamp -- I'm
not familiar with the Phllips lamp itself, but such strips have been
used as starting aids for lamps on rapid-start circuits in the past.
The strip makes it easier for the lamp to ionize with the available
ballast starting voltage.
Starting strips also allow a fluorescent lamp to be used with certain
ballasts in luminaires made of non-conductive materials since
normally with such ballasts the starting-strip function is provided
by the metal of the luminaire.
Terry McGowan
Post by John Gorce
Post by Jeff Waymouth
T5 technology employs a "cold spot" design which helps to maintain
proper mercury vapor pressure while operating. This is done by
mounting one electrode deeper within the lamp than the opposite one.
In OSRAM and OSRAM SYLVANIA products, the lamp etch (lable,
designation) is used to indicate the end with the deeper insertion.
While this end is down, convection currents within the lamp keep
that end at its proper temperature where it would overheat if it
were installed etch end up.
Jeff,
do you or anyone else know what a golden strip attached along the
length of the tube would be for?
The lamp is PHILIPS: TL AK 40W/03
V: 47
A: 0.880
Cap: G13
d: 38mm
L: 61 cm
The golden strip starts at one end cap, and ends at the opposite cap
and runs along the length of the entire tube. It looks like its
attached/etched on the glass.
Something to do with burning position maybe?
I've been wondering about this for some 20+ years now. I don't have
the lamp anymore, so thought maybe someone here knows what it's for.
The lamp's electrical characteristics seem to be identical to a
regular linear 40W fluoro, but I don't know anything about the
burning position because when I got it one of the electrodes was
cut, so I had to jump-start it by shorting it directly.
Many thanks,
Post by Jeff Waymouth
Jeff Waymouth
Post by TimR
In cases in which the lamps or luminaires are arranged vertically
or at an angle, the lamps must be fitted so that the end with the
type designation (stamp) is located at the bottom (coldest
necessary position for optimum luminous flux at the bottom). With
FC the circular T 5 and vertical arrangement, the lamp cap is to
be located at the bottom.
Why would this be so? In general, will any fluorescent fixture
work mounted vertically? The application I'm thinking of is to
mount one on the wall behind a tall plant.
--
I.
--
--
I.
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