what's wrong with this picture

[ship]

Gee, some highly paid professional lighting technions are better seved as professional gas station attendants. Can you tell what the problem is here in why this +$100.00 lamp in a +25.00 lampholder failed before either's expected life?

 

[Kelite]

Wow- that's quite a picture Ship!

(A little arcing problem perhaps?)

 

[tjrobb]

IIRC, HMI (etc.) lamps are supposed to be inserted filler pip up, to help heating. Beyond that, it looks like the lamp was never properly secured to the base, and again it looks like a bad arc fault of some type.

 

[fredthe]

Should this be phrased "OK, who is the nut that forgot the nut?"

-Fred

 

[ship]

Should this be phrased "OK, who is the nut that forgot the nut?"

-Fred

These types don't use a nut, this is a lamp from a Mac 2K fixture. Prope insertion, it's a Bender & Wurth lampholder, how typically do you mount one, think sping clip? Where is the screw thread in relation to the spring clip?

Hadn't noticed where the fill pinch is located.

 

[last125eagle]

I see it I see it!!! I know I know!!! * little kid in a class room*


They did not look at the manual. page 7 -9 of it to be precise.

http://www.martin.com/service/downloadfile.asp?name=UM_MAC2000ProfileII_EN_M.pdf&cat=65

 

[fredthe]

...Where is the screw thread in relation to the spring clip?

Makes sense now... I hand't seen that type of holder yet.

I'm not sure I'd trust them to put gas in my car properly...

-Fred

 

[DuckJordan]

it looks as though someone didn't wear gloves when placing this lamp in its socket nor did they clean off the bulb. that is what i would think unless they tried to force too many volts into the bulb

 

[Anvilx]

it looks as though someone didn't wear gloves when placing this lamp in its socket nor did they clean off the bulb. that is what i would think unless they tried to force too many volts into the bulb

Not quite sure how some one might force to many volts into the bulb or envelope. But through the lamp, perhaps.

 

[STEVETERRY]

Gee, some highly paid professional lighting technions are better seved as professional gas station attendants. Can you tell what the problem is here in why this +$100.00 lamp in a +25.00 lampholder failed before either's expected life?

This looks to me like:

1. The lamp was incorrectly installed with respect to the retention spring--the threaded portion of the lamp contact is on the wrong side of the spring, and therefore not physically seated to the bottom of the socket contact.

2. The fact that the lamp was sitting too high in the socket meant that it was too close to other metal structures in the fixture, presumably the reflector. Clearance distance for the high voltage ignition pulse was violated.

3. When the high voltage ignition pulse was applied to the lamp, it arced between the lamp contact and the adjacent metal structure. This created a sustained arc at the full ballast current that ate the metal structure, turned it to plasma, and deposited it onto the lamp contact, which is why one can observe metal buildup on the contact.


How did I do?

ST

 

[ship]

This looks to me like:

1. The lamp was incorrectly installed with respect to the retention spring--the threaded portion of the lamp contact is on the wrong side of the spring, and therefore not physically seated to the bottom of the socket contact.

2. The fact that the lamp was sitting too high in the socket meant that it was too close to other metal structures in the fixture, presumably the reflector. Clearance distance for the high voltage ignition pulse was violated.

3. When the high voltage ignition pulse was applied to the lamp, it arced between the lamp contact and the adjacent metal structure. This created a sustained arc at the full ballast current that ate the metal structure, turned it to plasma, and deposited it onto the lamp contact, which is why one can observe metal buildup on the contact.


How did I do?

ST

Hmm, better than I did I think. I assumed due to the bad contact we didn't get good sustained strike at some point and thus the immediate melt down of the base due to stress in noting the bent screw thread. Normally though I get an outer pinch failure from such a lack of good contact with the base due to heat generated. Base gets hot, on a B&W base we get arching, on an Osram base we get a tattoo, than with sustained use, the weld between lead in wire and monofoil goes super nova.

Given sections 2 and 3 of the above and the limited overall heat damage to the nickel plating, lack overall of arching and scaring to the lamp base where it contacts the socket and lack of damage to the above monofoil weld, I think it very plausable. Perhaps given the lamp hours yet lack of buildup on the electrodes for the age of the lamp, it took some time to overcome this high resistance arching to the reflector or what ever it arched to but finally did. Fixture also probably was very dim in use over those 474 hours it lasted and towards the end was dousing though it's interesting that the arc gap was still 7mm and the electrodes were not blackened. Could be more about that when and how it happened but for the most part correct I think.

Could also be that who ever installed the lamp initially didn't reset the lamp counter which means the lamp perhaps didn't even last say an hour. The bubbles and wear on the lamp supports this concept. Could be totally correct in what happened as opposed to that resistance over time and it finally happening option above. This would also be supported by the lack of heat damage to the base and weld to the monofoil. Thinking square on and the lamp counter was not reset to boot. (Makes it worse yet. Yep Gas Station attendant - as above, as long as they don't pump your gas and you can swipe your credit card at the pump.)

Electrodes lacks bubbles, screw thread bent, lamp installed on reverse side of lampholder spring clip, electrodes out of alignment, light vapor clouds, cement blackened on bad side. Main reason for going bad was the improper install though how and why the base melted and tin can crushed in doing so was curious and unusual.

Really good and thanks.

 

[STEVETERRY]

Hmm, better than I did I think. I assumed due to the bad contact we didn't get good sustained strike and thus the immediate melt down of the base, normally we get an outer pinch failure from such a lack of good contact with the base due to heat generated. Base gets hot, weld between lead in wire and monofoil goes super nova.

Given section 3 of the and the limited overall heat damage, arching and scaring to the lamp base and lack of damage to the above weld I think it very plausable.

Lasted 474 hours, bad electrode lacks bubbles, screw thread bent, lamp installed on reverse side of lampholder spring clip, electrodes out of alignment, light vapor clouds, cement blackened on bad side. Main reason for going bad was the improper install though how and why the base melted and tin can crushed in doing so was curious and unusual.

Really good and thanks.

Was there damage to any other metal grounded parts in the fixture? That slag had to come from somewhere if it flowed through an arc! If there is no other damage, I'm sad to say that my theory falls apart.

As lamps age, they may take longer to ignite. The fact that it went 474 hours might mean that it got to the point where the ignition pulse had an easier path to ground than through the lamp itself.

If there is no other arc damage in the fixture, perhaps it was a simple case of socket-to-lamp overheating.

ST

 

[ship]

Spare lamp that was installed into the new base left the building back in September, the lamp was changed this month somewhere in the US while out on tour. Never got back the origional lamp for the fixture that left with the tour in that fixture so I cannot say much.

Nor do I have access to the fixture or what replacement parts were sent out for it. Moving Lights/electronics repair department and my lamp tracking programs don't talk with each other. We get along and help each other but totally different departments and fiefdoms as it were with seperate computer programs for tracking stuff.

In other words, no idea of what happened to the fixture, I buy the bases and lamps and supervise them but after that, totally different part of the company all else.

In the past year I just started tracking bases with lamps as best I could and when I get that box for a change marked or the base back with the lamp, other than that impossible at this point yet to link up what's repaired with the lamps. Totally different worlds within one company but good question I also asked given the stated lamp hours.

On the other hand look at the electrodes. They lack a sufficient buildup of bubbles on the tips of the electrodes to support 400+ hours - this even with a voltage problem.. With a voltage problem there will still have been some buildup even if blackened, or micro crack (not evidenced) the bubble buildup will have been stolen away in still leaving behind a blackening of the electrodes. I can normally tell within a hundred hours or so the lamp's age if under 800 hours, these electrodes have not been in use long if at all. The bad side lacks bubbles, the other side has about as many silver bubbles on it as a new lamp.

Lack of bubbles on the same side of this melting probably means the arc as long as it was sustained ran thru the reflector or some part of the frame to ground as you said and not thru the higher resistance lampholder for as long as it lasted. Even the bent screw thread doesn't look like it had much heat damage. Just kind of bent. Thinking your origional concept is correct the more I think about it as to what happened here.