Can anyone tell me what the typical lumen outputs of "normal" mains
40W / 60W / 100W bulbs are or a website ? Also what the typical light output reduction is with age of the bulbs ?Be interesting to know how the CFL outputs compare and how different manufacturers products compare (e.g. Mazda / Osram etc )
Thanks,
Nick
"froggers" wrote | Can anyone tell me what the typical lumen outputs of "normal" mains | 40W / 60W / 100W bulbs are or a website ?
Referring to my "Mechanical World" Electrical Year Book the output of a lamp in lumens will be given by 4 pi Mean Spherical Candle Power. About one-half of one percent of the enegry input to a carbon filament lamp is radiated as light, compared to about one and a half percent in a vacuum-type tungsten filament lamp and about 3 percent in a large gas-filled tungsten lamp. The efficiency rises as the size increases and the efficiency drops as the voltage increases.
For Pendant Position Vertical, tungsten filament standard lamps not opals (Table III)
Watts Avg Lumens per Watt
15 6.70 25 7.20 40 7.13 60 8.73 75 9.54 100 10.43 150 11.52 200 11.97 300 12.78 500 13.86 1000 15.65 1500 16.73Table IV Typical lamp efficiencies
Lamp / Lumens per W / W per MSCP
Carbon fil, ordinary 3.0 4.2 Carbon fil, metallised 6.0 2.1 Nernst 8.5 1.5 Tantalum 8.0 1.5 Tungsten, vacuum 7.5-9.5 1.65-1.3 Tungsten, gasfilled 10-20 1.25-0.65 Open carbon arc DC 15 0.85 Open carbon arc AC 7 1.8 Enclosed carbon arc DC 9.5 1.3 Flame arc open DC 40 0.32 Magnetite arc 25 0.5 Tungsten arc 12.5 1.0 Mercury arc (in quartz) 55 0.23 Neon arc 25 035 Moore, N/CO2 8.5 1.5 ditto 3 4.2 Neon glow discharge 0.85 15
| Also what the typical light output reduction is with age of the bulbs ?
For Table III, output remains within 90% of original output within 1000 hour rated life.
Owain
What year is this? Looks like 1920's from the lamps listed...
Low pressure sodium -- 180 Lumens per Watt for the larger lamps
"Andrew Gabriel" wrote | "Owain" writes: | > Referring to my "Mechanical World" Electrical Year Book the output of a lamp | What year is this? Looks like 1920's from the lamps listed...
1934. The 'definitions and units' section includes a helpful comment that: the standard of comparison used to-day is the International Candle (or Bougie Decimale). A most useful little volume, although some of the circuits remain impractical until Buy & Queue start selling Lundberg Twinob switches :-)Owain
There is a very useful table at
The "normal" bulbs are near the bottom listed as "Incandescent (standard)"
Didn't as yet find manufacturers comparison tables...
Bare in mind, 120V US filament lamps are more efficient than 240V UK filament lamps, which will make the Incandescent and Tungsten Halogen tables wrong for UK comparisons.
Also, in the fluorescent lamps sections, US T8 runs at a different current from rest of the world which will affect the results, and T12 High-Output doesn't exist outside the US AFAIK. US regular T12 and T8 have higher control gear losses on magnetic ballasts than
220-240V countries, although the table ignores control gear losses.
And I was so pleased with myself... :(:(:( back to the drawing board...
Assuming that this comparison is valid for the UK, its interesting to note that fluorescent, metal halide, and high pressure sodium all have similar efficiency which is only half that of nasty yellow low pressure sodium. The council have just replaced all LPS streetlights near us with HPS ones that appear a lot brighter, although the light seems to be focused where its needed much more effectively than the old ones so perhaps they get by using the same power.
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