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Philips 70w MHN-T

Philips 70w MHN-T

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Two protected quartz metal halide lamps with PG12-2 caps. The early lamps (along with the SDW-T) featured a while plastic base but this was changed to metal on the later lamps because the plastic tended to discolour when in use.

An interesting lamp as it uses thulium, dysprosium and holmium iodides in the discharge mixture. Thulium is quite an aggressive halide and this would sometimes lead to arc tube explosions so two thick quartz shields were employed to allow safe operation.

The prefocused PG12-2 cap was selected to ensure excellent optical control when the small arc gap was positioned at the focal point of a reflector.

A photograph of the arcstream can be found here:
http://www.lighting-gallery.net/gallery/displayimage.php?pos=-99852

DPP00000746.JPG DPP00000711.JPG DPP_3619.JPG IMG_0583.JPG

Light Information

Light Information

Manufacturer:Philips
Model Reference:MHN-T
Lamp
Lamp Type:MBI-T
Base:PG12-2
Shape/Finish:T32
Electrical
Wattage:70w
Voltage:90v
Current:1a
Optical
Lumen Output:5500lm
Color Temperature:4200k
Color Rendering Index:85%
Physical/Production
Dimensions:149 x 91mm
Factory Location:Belgium
Fabrication Date:1F and 9L (June 1991 and December 1999)

File information

File information

Download: Download this File
Filename:DPP_3619.JPG
Album name:FrontSideBus / HID: Metal halide
Keywords:Lamps
File Size:2061 KB
Date added:Oct 23, 2014
Dimensions:1920 x 1280 pixels
Displayed:162 times
Date Time:2014:10:23 18:40:28
DateTime Original:2014:10:23 18:40:28
Exposure Bias:1 EV
Exposure Time:13/10 sec
FNumber:f 16
Flash:No Flash
Focal length:55 mm
ISO:100
Make:Canon
Model:Canon EOS 70D
Software:Digital Photo Profes
White Balance:1
URL:https://www.lighting-gallery.net/gallery/displayimage.php?pos=-99816
Favorites:Add to Favorites
Comments
Danny
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Oct 23, 2014 at 02:50 PM Author: Danny
Cool ive got one of these that ive never lit. I should light it at somepoint really!
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Oct 23, 2014 at 03:25 PM Author: Globe Collector
Nice find Mark. The white base one is quite a rare find. I'm still looking for a white base SDW-T and this is the first time I have ever seen a white base MHN-T.

When I was in Viet Nam I'm sure I saw one without the internal blast shield in a market there, but now I am unsure if a shieldless version ever existed and it was just a distorted memory.

The artwork on the boxes looks almost the same so these two must have been made at around the time the base change occurred. Can you see the date codes on each lamp? I'd love to know what they are!

Do these also have TWO concentric blast screen tubes?

Manufactured articles should be made to be used, not made to be sold!

Fee, Fye, Fow, Fum, A dead man's eye and a parrot's BUM!

FrontSideBus
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Oct 23, 2014 at 03:30 PM Author: FrontSideBus
Yeah the date codes are in the info fields.

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http://www.lighting-gallery.net/gallery/index.php?cat=11271

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Oct 23, 2014 at 03:34 PM Author: Globe Collector
Duh! 1F would be July 1991 and 9L (I assume is the white base one) is December 1989, so the base change must have occurred in 1990!

Manufactured articles should be made to be used, not made to be sold!

Fee, Fye, Fow, Fum, A dead man's eye and a parrot's BUM!

FrontSideBus
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Oct 23, 2014 at 03:38 PM Author: FrontSideBus
The White base one is 1F which I took to be June '91?
Yes they have two blast shields that can be seen when the image is viewed full screen.
Lots of engineering went into these for sure!

UK out of the EU!
http://www.lighting-gallery.net/gallery/index.php?cat=11271

Al_M
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GEC Z9464 90w SOX/LPS


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Oct 23, 2014 at 04:02 PM Author: Al_M
I used to sell these at the lamp shop in New Zealand. The poor sparkies eyes would water when he got the invoice for them...

Traffic signals & street lighting engineer. Please bring SOX/LPS back Downunder!!

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Oct 23, 2014 at 04:03 PM Author: Globe Collector
Sorry, you are correct, "F" is June not July. That is interesting that the white base one appears to be the younger of the two. This implies there was some considerable overlap and must have been both base types in the hopper of the capping machine or the lamps were made and stored, uncapped for quite some time prior to capping.

What a nonce, the "1F" is as clear as day in the photo on the white cap lamp!

Manufactured articles should be made to be used, not made to be sold!

Fee, Fye, Fow, Fum, A dead man's eye and a parrot's BUM!

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Oct 23, 2014 at 04:09 PM Author: Globe Collector
Hey Alister! Imagine buying a dual cage tantalum lamp in 1909, bet they had an "eye popping" price then too because of all the work needed to make them.

One of the factors in the high price, apart from the complex assembly, would be the Thulium Iodide. This is one of the "heavier" rare earth/lanthanon metals, and the heavier they get, the rarer they seem to get. Yitterbium and Lutetuim are up the heavy end too and are as rare and as expensive as hell when compared to Lanthanium or Cerium down the "ligt" end.

Manufactured articles should be made to be used, not made to be sold!

Fee, Fye, Fow, Fum, A dead man's eye and a parrot's BUM!

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Oct 23, 2014 at 09:43 PM Author: FrontSideBus
I'm sure that 9L would be December 1999. 1989 would be L9?
The metal base lamp also has the newer style Philips etch on the hard glass outer instead of on the cap.

UK out of the EU!
http://www.lighting-gallery.net/gallery/index.php?cat=11271

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Oct 24, 2014 at 12:25 AM Author: Danny
Yep FSBs info is correct 1F is june 1991 and 9L is november 1999 philips date codes are easy!!
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Oct 24, 2014 at 01:30 AM Author: Globe Collector
I think I was misled by the packet artwork as these two dates are nearly a decade apart, I would have thought that artwork would have changed during that time, and 9L is 1999 I was incorrect.
Bit of a pity really because the time window between them is so large it does not really pinpoint the phase out of the white base to any great precision. My metal capped MHN-T has date code 7K, but that is still quite a while after 1F.

Manufactured articles should be made to be used, not made to be sold!

Fee, Fye, Fow, Fum, A dead man's eye and a parrot's BUM!

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Oct 24, 2014 at 02:04 AM Author: monkeyface
These are very nice lamps. The shroud glows in a nice blue colour after the extinguishing.
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Oct 24, 2014 at 02:54 AM Author: Globe Collector
I thank you very much for that lamp Michael, it is still one of my favourates!

I still hunger for a Tekfen mercury though.....

Manufactured articles should be made to be used, not made to be sold!

Fee, Fye, Fow, Fum, A dead man's eye and a parrot's BUM!

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Oct 24, 2014 at 11:20 AM Author: FrontSideBus
Photo of the arcstream uploaded.

UK out of the EU!
http://www.lighting-gallery.net/gallery/index.php?cat=11271

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Oct 24, 2014 at 03:22 PM Author: lantern_vision
Those are awesome.

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