Amount of light from linear floodlamp bulb

[JS]

I am referring to those linear tungsten halogen light bulbs often
used by domestic floodlights for outdoor use. These bulbs are 117mm
long.

http://www.theelectronicsshop.co.uk/Spares/k9 lamp.htm

This link shows an output of 4,600 lumens for an input power of 150
Watts.

 

[Victor Roberts]

I am referring to those linear tungsten halogen light bulbs often
used by domestic floodlights for outdoor use. These bulbs are 117mm
long.

http://www.theelectronicsshop.co.uk/Spares/k9 lamp.htm

This link shows an output of 4,600 lumens for an input power of 150
Watts.

-----

Do other 117mm bulbs (300 W, 500, etc) have a lumen output
proportional to their power consumption which is equivalent to one
another? IYSWIM.

Not necessarily. The efficacy of a lamp, measured in lm/W,
is a function a number of design parameters, perhaps most
importantly the filament temperature which determines the
trade-off between light output and life. It seem to be an
easy matter to check the lamp specs.

--
Vic Roberts
http://www.RobertsResearchInc.com
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[CWatters]

I am referring to those linear tungsten halogen light bulbs often
used by domestic floodlights for outdoor use. These bulbs are 117mm
long.

http://www.theelectronicsshop.co.uk/Spares/k9 lamp.htm

This link shows an output of 4,600 lumens for an input power of 150
Watts.

-----

Do other 117mm bulbs (300 W, 500, etc) have a lumen output
proportional to their power consumption which is equivalent to one
another? IYSWIM.

Light output should be reasonably proportional to power input for a given
technology. Will probably vary from make to make.

Just for info halogen lamps aren't particularly efficient. In the UK an
energy efficient lamp as defined as producing more than 40 lumens per watt.
I think only flourescent lamps can meet that but some prototype LEDs are are
also in the ballpark (but not yet commercially available I think?)

 

[dennis@home]

Just for info halogen lamps aren't particularly efficient. In the UK an
energy efficient lamp as defined as producing more than 40 lumens per
watt.
I think only flourescent lamps can meet that but some prototype LEDs are
are
also in the ballpark (but not yet commercially available I think?)

IIRC high pressure metal halide lamps are much more efficient than
fluorescents

 

[Andy Resnick]

I am referring to those linear tungsten halogen light bulbs often
used by domestic floodlights for outdoor use. These bulbs are 117mm
long.

http://www.theelectronicsshop.co.uk/Spares/k9 lamp.htm

This link shows an output of 4,600 lumens for an input power of 150
Watts.

-----

Do other 117mm bulbs (300 W, 500, etc) have a lumen output
proportional to their power consumption which is equivalent to one
another? IYSWIM.

Tungsten halogen bulbs typically have an efficiency of about 25 lm/W

http://vsg.cape.com/~pbaum/halogen.htm

Your guys claim about 30 lm/W... close enough.

So within reason, the light output is proportional to the wattage, all
things equal (bulb design, reflector geometry, etc. etc)

 

[Andrew Gabriel]

IIRC high pressure metal halide lamps are much more efficient than
fluorescents

Actually, linear fluorescents are slightly better than metal halide
lamps, although there isn't much in it. Other high intensity discharge
lamps will do better, although their colour rendering is not as good.

 

[Victor Roberts]

IIRC high pressure metal halide lamps are much more efficient than
fluorescents

I disagree. Linear T8 and T5 fluorescent lamps operate with
an initial efficacy of 100 lm/W or better on electronic
ballasts and have mean efficacy values that are just about
95% of the initial (100 hour) efficacy values.

Pulse start MH lamps have about the same initial efficacy,
but their mean efficacy values are only about 70% of the
initial value, and that's for a 15,000 lamp vs 20,000 hours
for the linear fluorescent lamps. Conventional metal halide
have lower initial efficacy values until move up to the very
large sizes. For example, one GE 250-watt metal halide has
an initial efficacy of only 83 lm/W and a mean efficacy of
54 lm/W. On the other hand a 1650-watt GE metal halide lamp
has a respectable initial efficacy of 107 lm/W, but the
rated life of this lamp is only 3000 hours and the mean
efficacy value is 88 lm/W.

CMH lamps still don't beat fluorescent in raw efficacy. A
400-watt Philips MasterColor CMH lamp has an initial
efficacy of about 87.5 lm/W and a mean efficacy of 74.4 lm/W
while having a rated life of 15,000 hours. A 70-watt Philips
MasterColor CMH lamp has an initial efficacy of
94 lm/W, and a mean efficacy of 71 lm/W. So, the performance
does vary with the type and size of the CMH lamp, but I
can't find any that have higher efficacy than good 4-foot
fluorescent lamps.

Now, before I get beat over the head I must state that I
know there are factors to consider other than raw efficacy.
Each lamp type has advantages and disadvantages in specific
applications. I am only responding to your comment that high
pressure metal halide lamps are mush more efficient than
fluorescent lamps..

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
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It may not be used in any publication or posted on any Web
site without written permission.

 

[JS]

Tungsten halogen bulbs typically have an efficiency of about 25
lm/W

http://vsg.cape.com/~pbaum/halogen.htm

Does this efficiency figure vary between bulbs which are linear
and bulbs which are not?

 

[Andy Resnick]

Does this efficiency figure vary between bulbs which are linear
and bulbs which are not?

I imagine it varies from bulb to bulb, if you are measuring accurately
enough. But I don't think that's what you mean. I don't know enough to
say, but I would not be surprised if your statemnet is true.

 

[TKM]

I imagine it varies from bulb to bulb, if you are measuring accurately
enough. But I don't think that's what you mean. I don't know enough to
say, but I would not be surprised if your statemnet is true.

Yes, the efficacy does vary somewhat between the different types; but it's a
matter of a few percent at most. The efficacy of a halogen lamps is
basically determined by the filament temperature. Filament construction,
loading, end losses due to filament supports, gas mixture and other design
parameters will affect efficacy, but in a minor way - at least for the
general lighting lamps that I've used.

Terry McGowan