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Philips SDW-AR 22W : Power Curves

Philips SDW-AR 22W : Power Curves

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These graphics show the performance of replica I built of a Philips Crown Silver SDW White SON lamp. Due to the excessive radiation reflection from the mirrored bulb onto the arc tube, which causes its temperature to increase, the lamp must be under-run to attain the correct arc tube temperature, sodium vapour pressure, and spectrum. In an attempt to determine the correct lamp power I operated it across the range from 10W to 35W in 5W steps, and the results are plotted in the graphics here. It is clear that from the power vs flux curve, maximum luminous flux is achieved at about 22W. This also corresponds with the intended 2500K colour temperature of the lamp, and since the Δλ separation also attains the correct value at this loading, it would seem that this lamp is best operated at approximately 22W.

It is interesting to note that at higher powers, the colour temperature increases very rapidly - at 35W lamp it produces a slightly greenish cool white spectrum of around 5000K!

D SHP Philips SDWR50.jpg D SHP Philips SDWAR22.jpg D SHP Philips SDWAR22 powercurves.jpg D SHP Westinghouse C70S62PAR side.jpg

Light Information

Light Information

Model Reference:SDW-AR 22W
Lamp Type:Sodium High Pressure
Filament/Radiator Type:Philips SDW-T 35W arc tube
Wattage:22 W
Voltage:102 V
Current:0.28 A
Lumen Output:550 lm
Lumen Efficacy:27.5 lm/W
Color Temperature:2500K
Color Rendering Index:80
Dimensions:104.5mm x 60mm
Factory Location:Belgium
Fabrication Date:Arc tube : 1986. Outer jacket : November 2018
Application/Use:Retail display lighting

File information

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Filename:D SHP Philips SDWAR22 powercurves.jpg
Album name:James / Sodium High Pressure
File Size:305 KB
Date added:Dec 03, 2018
Dimensions:2465 x 1641 pixels
Displayed:77 times
DateTime Original:2018:12:02 23:55:29
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Dec 03, 2018 at 06:40 AM Author: rjluna2
Thank you for sharing the detail on the power analysis, James

Pretty, please no more Chinese failure.

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Dec 03, 2018 at 11:52 AM Author: Max
The power scan is often the best way to characterize the properties of an HID lamp, especially if you try to find its optimum operating point. This is quite a lucky coincidence that your lamp happens to operate best on Philips' 22 W CDM driver (I suppose this is what you ended up using?).

Quote from James

at 35W lamp it produces a slightly greenish cool white spectrum of around 5000K!

Wanna see some pretty extreme optical emission spectra from a SDW lamp? Then check this out (this is not for the faint of heart!)
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