In the lamp catalog of METROPOLITAN-VICKERS from 1952, there is a lamp MA/H 2500W in the table of mv-lamps.


Source: METROVICK lamp catalogue 1952, page 20

I do not assume that this is a printing error. It could have been a lamp for photochemical or repographic purposes.
Has anyone ever seen this lamp with 2500W or even heard or read about it ?

Indeed it is real.  There is a photo of an earlier one on my page at http://www.lamptech.co.uk/Documents/M8C%20MA%20Lamp%20Developments.htm
The final production lamps had G38 bi-post bases as used for the 2/5/10kW incandescents.  I have only ever seen one before, at the old GE/Thorn collection of the Leicester factory where I used to work.  That was in the days before digital photography, so I did not ever make a photo of it.

Hello Olav,

Like James said, this lamp indeed existed. The lamps that was later made and which is also written about in your catalogue has the G36 Large Bi-post base or otherwise called G38. This is a common base with optical and projector lamps. For example the CP14, CP41, CP83 or CP85 studio incandescent and halogen lamps or the Osram HMI in 1.2, 1.8, 2.5, 4 or 6kW metal halide lamps use that base.

I find it most interesting that these lamps are single ended with single base and not double ended like the BTH variety on James website or the (even thue much longer) GE H9 lamp. I somehow have the feeling that this 2.5kW MA lamp was made for a special fitting by Metrovick were a single ended lamp was preferred.

I actually think I even have once seen a picture of these Metrovick lamps in the collection of a collector who is not a member of this website anymore.


I also noticed something. The page Olav scanned mentions the MA/U lamp in both soft and hardglas. Was there another reason apart from cost savings?



best regards,

Alex

Interesting details Alex.  The one I remember from GE/Thorn was double-ended with G38 cap at both ends.  One pin was for the main electrode, the other for the ignition electrode.

Thanks for all the answers and comments.

Would it be reasonable to assume that the MA/U 250W and MA/U 400W lamps with soft glass and hard glass outerbulbs were used for closed and open fixtures respectively ?
I am thinking of water splashes caused by rain. Hard glass, on the other hand, is supposed to be somewhat more resistant (i.e. it doesn't crack immediately) or am I on the wrong track?