Author Topic: Differences in the details of the GEC OSRAM MA/V 250W and MA/V 400W lamps  (Read 2218 times)
Olav
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Olav Kettner
Differences in the details of the GEC OSRAM MA/V 250W and MA/V 400W lamps « on: October 10, 2024, 11:22:53 AM » Author: Olav
Rather by chance, a topic has arisen concerning many small differences in detail on the MA/V 250W and MA/V 400W lamps manufactured by GEC OSRAM:

- one starting resistor or two starting resistors
- one “zigzag” support or two “zigzag” supports
- different voltage specifications

This article could become a good overview if enough owners of these lamps would participate and post new photos of their lamps here.
The request would be: take new pictures in portrait format and include the lamp diagonally from bottom left to top right.
Please include the date code or insert it as a reduced image in the photo of the lamp. A page width of 1280 pixels for the narrow side would be favorable.

I'll just make a start now:



MA/V 250W , Code 92 (August 1957) , 230V-240V , two starting resistors in parallel circuit
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Alex
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feel free to ask questions


Re: Differences in the details of the GEC OSRAM MA/V 250W and MA/V 400W lamps « Reply #1 on: November 14, 2024, 01:12:57 AM » Author: Alex
Hello Olav,
Here are my two lamps:


https://www.lighting-gallery.net/gallery/displayimage.php?album=lastup&cat=12274&pos=10&pid=224759
250W: c.1955-1960 NATO Surplus a single arc tube holding spring and two parallel carbon resistor for one ignition electrode in the top.


https://www.lighting-gallery.net/gallery/displayimage.php?album=3934&pos=0&pid=224760
400W: c. 1955-1960 NATO surplus two arc tube springs one single carbon resistor and ignition electrode at the base.


I further did some research in the web:

400W

http://www.lamptech.co.uk/Spec%20Sheets/D%20MA%20GEC%20MAV400.htm
James' last generation of GEC lamp: 400W same as mine with the change from a brass to a nickel plated brass base

https://www.lighting-gallery.net/gallery/displayimage.php?album=search&cat=0&pos=25&pid=238406
400W: 1962 NATO surplus two arc tube springs one single carbon resistor and ignition electrode at the base.

http://lampenmuseum.de/details.php?image_id=1429
Rigo's 400W MA/V lamp, here the construction is mor similar to my 250W lamp with one single carbon resistor on the lamps top


250W
https://www.lighting-gallery.net/gallery/displayimage.php?album=search&cat=0&pos=22&pid=242199
A MA/V lamp from 1959 with a single ignition resistor in the bottom.

https://www.lighting-gallery.net/gallery/displayimage.php?album=search&cat=0&pos=39&pid=224827
A MA/V lamp from 1959 with a single ignition resistor in the bottom and nickel plated base


trying to find an evolution:
The newer lamps have the resistor at the base. The switch from brass to nickle plated brass was around 1962/1963.

Eventually the 250W got its second holding spring back.

best regards,
Alex

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Glück auf ⚒️

Olav
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Olav Kettner
Re: Differences in the details of the GEC OSRAM MA/V 250W and MA/V 400W lamps « Reply #2 on: November 15, 2024, 02:28:43 AM » Author: Olav
Hello Alex,

thank you very much for your work with the additions and tips. It's interesting to compare the individual variants within this lamp-design.

Best regards

Olav
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