Re: Zenon discharge lamps

[ChuckKuecker <ckuecker@mcs.net>]

At 19:01 4/22/97 -0700, you wrote:
>
>  Anyone know if there are any manufacturers that make round 5.75"
>zenon discharge lamps?  I have seen em on the newer Bimmers, Mercedes
>and Porsches.  I figure sooner or later someone will make em, just want
>to know if anyone has any insight to this?
>
>  Andre'

Actually, the lamps are 'metal halide arc lamps', not xenon. Xenon is what
is used on the cop helicopters - VERY expensive, and the bulbs don't last long.

Philips in Europe makes the bulbs for most of the cars. The headlights
(reflectors)
are custom for each car, far as I know. Last time I checked, they were about
$30 per
bulb, without the ballast (probably another $150).

The bulb requires an electronic ballast unit to operate, and runs on high
voltage
(about 30 kV) at the start-up, so it would be a non-trivial job to fit it into
the reflector of your choice.

I can state from personal experience - it IS possible to fit this kind of
bulb into
a different reflector, and run it successfully. A friend of mine built a
headlight for
his bicycle with one he got as an 'engineering sample', and so did I. SUPER
white and
bright, and they only use about 25 watts of power..

If you are electronically inclined and want to try it, I can send a
schematic of the
ballast we built. It runs on 12 V, so it would work in a car nicely.

The only troubles I have seen with these lamps are that sometimes, if you
hit a good
sharp bump, the lamp will 'blow out', and then it takes a while to cool off
before it
will relight. The other problem is it takes about 30 seconds for the lamp to
come
up to full brilliance from a cold start. I think the automotive ballasts
have circuits
that fix these..

Chuck Kuecker

ckuecker@mcs.net

'83 Scirocco
'58 Ghia Convert
'67 Bug
'63 Bug
'91 Vanagon


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