Film-Tech Forum ARCHIVE: Osram Bulb Analysis=High Inrush/High Current Ripple -Poor Power Supply Question

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Topic: Osram Bulb Analysis=High Inrush/High Current Ripple -Poor Power Supply Question

Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

posted 03-13-2005 03:49 AM

quote: Bob Brown
What exactly is meant by the term "reburned"? What is the "reburning" process

..much as I can gather is that the bulb is arced under very high amperage-higher than the bulb's amp settings, to "season" the cathode/anode plugs inside the envelope. This procedure is done with an "Off/On" sequence many times within a time frame.

..but don't quote me, for this is just what I've heard.

-Monte

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 03-13-2005 04:48 PM

There are people getting good life from Osrams but wait till they send that one troublesome lamp in for warranty... they will be awakened when they read Hi Inrush and ripple on their lamp repirt and finally realize why most people that use them eventually switch over to Chriistie.

Monte,
with switchers which operate in the mid 30 khz region high inrush current is not caused by transistor failure. The output of the switcher goes into a small high frequency/high current transformer of which the secondary is rectified and that DC is sent to the lamp. Hence bad or intermittent transistirs cannot cause high inrush current. Your main problem is the X-90 and its poor ventallation system. The only way to handle it is with about 800 to 900 cfm of air movement per console!!

Mark

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Richard May
Phenomenal Film Handler

Posts: 1057
From: Floral Park, NY USA
Registered: Aug 2004

posted 03-13-2005 09:49 PM

If I get one troublesome lamp from Osram out of all the theaters that I service that use them, compared to the number of Christie bulb problems that I have dealt with, I'll take that anytime. [thumbsup]

I don't understand why Osrams work for some and Christies work for some. It makes no sense. But from what I have been hearing here, it seems that it is the case [Confused]

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Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

posted 03-13-2005 10:07 PM

quote:
The only way to handle it is with about 800 to 900 cfm of air movement per console!!

Then, what's funny then is why doesn't STRONG recommend such a exhaust requirement of such magnitude then if such problems like these point towards the exhaust remedy?

Granted, that "muffin" fan concept that blows on the anode connection of the bulb is about as goofy of a design that I've ever seen. Prob why I can't get great hours when running a 2500k bulb in an X-90 console - not enough airflow going across the anode seal. They should take the blower hose concept of the SLC-45 consoles of Christie to cool down the anode connections. Then they would have something!

...another one of those "go-figure" things from Strong, I guess.
(thx Marko, on this..)

-Monte

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 03-13-2005 10:28 PM

quote: Monte L Fullmer
Then, what's funny then is why doesn't STRONG recommend such a exhaust requirement of such magnitude then if such problems like these point towards the exhaust remedy?

Thats something that ALOT of people have been trying to figure out for years!! It just may be that they also sell parts and Xenon lamps too...... or that they just don't quite have it together.... a bit of both I would presume.....

Mark

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Stephen Frazza
Expert Film Handler

Posts: 161
From: Nutley, NJ, USA
Registered: Mar 2004

posted 03-14-2005 02:56 AM

We had trouble again with a almost new bulb in this lamphouse, not wanting to ignite at all.But we had a spare rectifier so I changed it out and all seems to be ok now.

quote: Monte L Fullmer
How old is that X-90 console anywho? on the "X-90" faceplace, there is a manufacturer date when the console was built.

Monte the face plate says 3/91

Some more questions;
the bulb adaptor on the cathode side and the 2 cables to the anode and cathode side of the bulb, do these go bad.
I mean does the resistance in them goes up and it gets harder to push current threw them.
Is there any way to check this?
Or if not when and how often should you switch to new ones?

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Monte L Fullmer
Film God

Posts: 8367
From: Nampa, Idaho, USA
Registered: Nov 2004

posted 03-14-2005 03:08 AM

quote: Stephen Frazza
the bulb adaptor on the cathode side and the 2 cables to the anode and cathode side of the bulb, do these go bad.
I mean does the resistance in them goes up and it gets harder to push current threw them.
Is there any way to check this?
Or if not when and how often should you switch to new ones?

The big secret is to have any connection TIGHT! Electricity, especially DC, loves to find weak spots and heat up things to oblivion.

The anode cables are sealed on the anode ends and thus never any problems with these. It's just the "O" ring blade connection cable to the positive shunt with that brass screw must be TIGHT!

Same thing with the cathode adapter end being brass: must have TIGHT connections to the cathode end of the bulb. Anytime it get's loose, it will actually melt the brass down due to the immense heat from the resistance buildup.

I've only seen spattering of heated cables where the age of the bulb can take so much and the metal seals on the ends of the bulbs get tired and will break down with massive resistance, thus get real dark. If the bulbs gets this way, time for a change, or a defective manufactured bulb.

KEEP your connections TIGHT, Tight, Tight. And you won't have any problems.

-Monte

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