T3D Re: Projection Lamp 3-letter code (TECH-3D digest 542)

[Tom Hubin <thubin@xxxxxxxxx>]

Hello Bob Howard,
 
> RE: Ron laments confusion over specs of vast number of 3 letter
> code projection lamps and says "Why don't they do it like radio
> and TV tubes?" This got my attention as I was the engineer that
> suggested the three letter codes in ASA meetings, so we could
> pick a lamp as easy as a 6J6 radio tube!!!!

The exact substitution method works fine. There is only a problem when
you want to make a substitution or modification that is NOT an exact
substitute. This is the same as radio tubes. You need to get the specs
and interpret them. Unlike tubes, the specs are not in the public
domain. At least, I have not been able to find them free or cheap
anywhere.
 
> It was eventually adopted and were ASA listed (now ANSII codes).
> Before THEN one had to order a lamp by filament, base, bulb
> shape, and diameter as well as wattage and voltage (in 5 volt
> steps).
> e.g  1000 watt, 120v T-12, med. pref. base C-13D filament.

I have been able to get lamp catalogs with some specs from
manufacturers. None of them list filament size or shape. This is an
important parameter in a projector. I usually find a handful of possible
substitutes by matching all of the other parameters. Then start calling
manufacturers and talking to application engineers to get the filament
dimensions. This is time consuming, both for me and my phone bill, and I
often come up with nothing. The other method is to locate the lamps
locally and go measure the filaments.
  
<snip>

>  I have been away many years (1955) from Westinghouse Lamp
> Division (now owned by NORELCO). But I see the problem as not
> having a list of lamps. Makers used to put out lamp catalogs for
> projectors etc. and ANSI should have a list of the 3 letter codes
> and what they mean. I will take a search engine look to see if I can
> find ANSI lamp codes. BobH

I have been told that the ANSI specs for lamps can be bought but not
copied. If they can be had cheaply and legally I would like to have the
specs myself. It would help me to design or modify projectors.

Tom Hubin
thubin@xxxxxxxxx
AO Systems Design