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BULB DISCUSSION BOARDS => Antique Bulb Discussion => Topic started by: ALM on July 21, 2001, 09:04:00 pm

Title: Identification of new acquisition...
Post by: ALM on July 21, 2001, 09:04:00 pm
I don't think that this is old, but I grabbed it because it was the first of its kind I've seen.  I'm not sure if the base is copper, brass, or whatever.  Maybe a projector bulb?

Lemme know what you think.  And thanks!

150W, 120V, 15HR



Title: Identification of new acquisition...
Post by: ALM on July 30, 2001, 01:17:00 pm
Anybody?  Anybody at all?
Title: Identification of new acquisition...
Post by: Tim on July 30, 2001, 02:12:00 pm
ALM,

Little (if any) collector value on this bulb, however someone wishing to replace a bulb in their vintage projector may find it attractive.

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-Tim
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Title: Identification of new acquisition...
Post by: Chris W. Millinship on July 30, 2001, 03:17:00 pm
This collector has a liking for the odd ones, whether new or old, however I agree with Tim that most others wouldn`t really consider it.

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Title: Identification of new acquisition...
Post by: Bob Masters on August 01, 2001, 09:04:00 pm
One interesting note about odd-ball bulbs like that. Some types are extremely short-run, custom focused and certified bulbs. Very rare in the whole scheme of things.
For instance, order a replacement bulb for a set of old cabinet style lab-grade Mettler precision scales. New should set you back about $30++ apiece, and they have to be ordered.
Those will be the rarest-of-the rare in the future.

Just my two cents worth !
-Bob-
Title: Identification of new acquisition...
Post by: Bob Masters on August 01, 2001, 09:11:00 pm
http://daeitswp2.mysylvania.com/scripts/wgate.dll/zb2cpcat/!?~language=EN&~template=FRMSTART&~shop=GL-L0 (http://daeitswp2.mysylvania.com/scripts/wgate.dll/zb2cpcat/!?~language=EN&~template=FRMSTART&~shop=GL-L0)

Matter of-fact try that Sylvania site and use the "search" feature. You may be able to find out what it's for. Good luck Tony !
-Bob-
Title: Identification of new acquisition...
Post by: Scott on August 01, 2001, 09:27:00 pm
My guess is a projector bulb of some kind, tho' not necessarily one for a movie projector-looks like the one out of an overhead projector in a way. The base really doesn't look like brass,but that odd gold color of anodized aluminum. Just guesses.
Title: Identification of new acquisition...
Post by: James on August 01, 2001, 09:56:00 pm
Hi, I see from the monogram on the top of this bulb that it is marked DCH.  This identifies it as a 120V 150W lamp for use cap down ONLY in an 8mm movie projector.  Its internal aluminised mirror focuses the light down onto the film at a point 2.25" in front of the bulb.

This design is interesting because it employs a ballast filament which is at the side of the reflector.  This allows the lamp to be driven from 120V supply but some voltage is dropped across it, and the main filament at the focus of the mirror is a low-voltage type.  The low voltage filaments last longer and are considerably more efficient.

Although your lamp looks 20 years old, DCH is still in production today and they sell for about $20 each.  A few years ago you'd get them for under $10 but they are not made in large volumes these days, so the price is higher.
Title: Identification of new acquisition...
Post by: ALM on August 02, 2001, 08:30:00 am
Thanks guys!  I also believe the base to be aluminum.  It's very "light" metal.

A sharp looking bulb in any event.
Title: Identification of new acquisition...
Post by: Bob Masters on August 02, 2001, 10:38:00 am
How cool !
Sounds like an elipsoidal reflector system kinda like the automotive headlamp projector
lamp systems where the secondary reflector focal point intersects the focal point of an inverted parabolic lens. Very handy for lighting a cigarette while demonstrating the heat that is concentrated at the elipsodal focal point...........Ha Ha Ha.......
and we used to get paid for that............
Title: Identification of new acquisition...
Post by: ALM on August 02, 2001, 02:00:00 pm
quote:
Originally posted by Bob Masters:
Very handy for lighting a cigarette while demonstrating the heat that is concentrated at the elipsodal focal point...


???

Anybody suffer burned lips or face?

Title: Identification of new acquisition...
Post by: Chris W. Millinship on August 02, 2001, 04:25:00 pm
An elipsoidal reflector has 2 focal points. The lamps Bob was referring to would have had the filament in the bulb positioned at one focal point, and the other would converge outside the lamp in front of it. The A1/17 projector lamp (http://electriclights.tripod.com/bulbs/a117.htm) has a similar configuration. Basically, at that external focal point, the light and subsequent radiated heat is so intensely focussed that it is almost as if the filament were at that point too. Stick a bit of paper or cigarette end there and it`ll burst into flames!

I know. I tried. I wasn`t expecting the piece of paper to catch fire, just smoulder a bit. I was wrong to think that.

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