The above Ad will no longer appear after you Sign Up for Free!

Mac 2K lamp observation question

Discussion in 'Lighting and Electrics' started by ship, Jul 30, 2008.

  1. ship

    ship Senior Team Emeritus Premium Member

    Messages:
    6,173
    Likes Received:
    447
    Location:
    Illinois
    A bit more involved in concepts than Question of the day thus presented here.

    A) new fixture, why do they seem to be able to run a lamp 3x past their expected lamp life to the ground at times without a problem in lamps removed from them don’t really seem much worse than lamps run at 50% past their lamp life if even that?

    B) is there any correction between lamp life and fixture/ballast age?

    C) why if given a globe is fairly clear, will a lamp that seemed low in output in one fixture, be often fine in another fixture if under say 500 hours, yet it mostly not live up to beyond like 750 hours even if in a new fixture as second install? This for the most part?

    Finally had a chance to inspect some lamps over the last couple of weeks. Specifically some lamps coming off a tour that’s been out for about 15 or more months now. They dependant on fixture location are either on their second or third round of lamp changes for that tour at this point.

    Beyond fixture brand with some brands of first lamp in brand new fixture having a preclusion for that lamp base going bad than taking out the lamp after say 600 hours, - possibly in not at this point having studied the problem in depth yet, being a case of those that got the serial numbers off the lamp or installed it originally didn’t properly seat the lamp in it later destroying the lamp base or other problems in discounting brand of lamp socket that was in this case different. And in study beyond a noted lack of lamp life of one brand over another which is fairly well researched and shown to be the case, but in this case only one brand the longer life brand was in use which comes to issue now.

    What I’m noting is unique so far to this long tour that might be similar to what one might expect in a non-touring/short show situation . Seems amongst the new and used fixtures sent on the tour, and given lamps were changed by truss section and when blown in numbers, or really dark only and not by way of expected lamp life ratings for replacing all at once, I’m noting something interesting. Those brand new lamps in new Martin Mac 2K fixtures (not persay exclusive to the brand more that they are new - see above) lasted sufficiently in output up to and for the most part between 2,000 and 2,350 hours in lamp life before they needed to be replaced in the bulk of them.

    This for a 750hour rated lamp. The rest of the lamps in being replaced normally lasted overall in the 1,000 to 1,300 hour range with a spike around the +1,200 hour range dependably. This granted the tour has not been changing lamps persay when recommended, more when they needed to or the show started getting more dim or washed out than remembered. This or the tour had time to be changing in bulk a section at a time.

    Main observation on over a hundred lamps now that were the first lamp installed in a brand new fixture was that they lasted between 2,000 and 2,350 hours in lamp life. With older fixtures, they were normally replaced out of need at around 1,250 hours. A few lamps overall to all which didn’t live up to expected lamp life overall no doubt, but the bulk of them lasted in both situations that long in providing sufficient light for the tour that a lamp change was not required.

    First lamp in a fixture that lasted that long as confirmed by way of computer lamp tracking - each time we get in a new lighting fixture I in signing in the lamp serial number and assign it to that fixture along with in the notes section assign that original fixture’s manufacturer barcode number to the lamp also. Helps a lot at times when the serial number gets lost or freelancers sign the fixture as it’s barcode instead of serial number. Not so much when they assign the fixture to fixture location on a lamp plot, but at least covering most of my bases in figuring out what fixture a lamp was assigned to. As long as the person removing the fixture signs like five questions on each new lamp as to what they are doing with someone’s day rate in pay for installing that new lamp, I have all the info I need to make a warranty claim to the lamp or at least analyze it amongst the other like 15K worth of lamp serial numbers tracked. Do a search into something like pinch/globe coning... crack and I can pull up how many lamps at least in the past year I have observed with this condition where there was a failure forming by way of wee crack detected under a magnifying glass, and at what hours that took place on as a trend or lamp mortality sub-figure in what destroys a lamp.

    None the less, the above lamps living past 3x their expected lamp life while in new fixtures has been confirmed. Crew chief on show has been working with moving lights longer than I, has about a 99% accuracy rating in doing lamps and the volume of lamps having this amount of lamp hours in both cases has been confirmed by observing electrode bubbles.

    One can with experience in looking at lamps, by way of amount of lamps inspected to some extent be able to tell within like 100 hours how many lamp hours that lamp has been in use overall without any fixture lamp counter telling me this. Often test myself and am rarely other than fairly well accurate given around over a thousand lamps inspected per year. Look at a new moving light lamps electrodes and compare them to one of various hours. Unless there was a microcrack failure that let the gas out, often the electrodes will by way of silver bubble build up on them easily at least for a Mac 2K type lamp tell you how many hours that lamp has been in use. For a 1,000 hour lamp thru say 1,300 hour lamp (this range is harder to tell a bit), you get like a bit less than 1/8" in dia x 3/16" long buildup. These lamps used over 2,000 hours had a buildup of like just under 1/4" dia. By 1/4" long on the electrode.

    That’s electrode alone, buildups/crusties, clouds, snow, frost, haze, vapor clouds, fill pinch crusties, polar crusties, pinch/globe coning, inner pinch electrode bubbles, inner pinch cracks forming, outer pinch cracks forming, lamp base heat damage. Etc. Amongst stuff like elephantisus/divitrification and on or off axis lamp twists are all things I describe each end result of lamp for in describing like a +$100.00 each lamp thus deserving a bit more observation than how clouded its outer globe is in either sending it back or not. Physically these days put each lamp in front of a lighted 7x magnifying glass and inspect it for a number of concepts in it so as to determine if operator error in not filling out a tag thus not a lamp I can send back, a lamp I can send back, a lamp to try again in verifying it’s bad or should be fine on a different ballast, a lamp that is bad or marginally so etc. All about saving like $30K or double that a year in lamps by way of tracking and inspection.

    Back to the new fixtures and lamps that lasted. Fascinating in that I have found that if a lamp lasts up to 1,200 hours and still looks good by way of fairly clear globe and not too much coning or fill pinch etching as it were (coolest spots in the lamp), often these lamps in a new fixture do tend to be able to last as long as 3x the lamp life if in a new fixture, otherwise if left alone and original for that lamp to a fixture, they often will last up to 1,200 and more hours. No not optimum and often there will be output and or color temperature changes, but they do function on tour persay if left alone that long very dependably.

    Still, of note is lamp life changes to a lamp I see. Between say 1 and 300 hours, that’s where most etching, coning and attacks on the coolest areas of a lamp take place, and often a say inner pinch crack in the lamination happening at this point while it’s still there won’t expand at least on a 1.2Kw lamp often. Often or mostly that’s also where a failure of a pinch by way of micro crack that lets gas out but maintains lamp integrity be it lamp base pinch or fill pinch will take place in lamp hours. Pinch failures are often catestropic and often the case of either a bad fixture lamp socket in overheating a lamp or a micro crack that develops by way of long term etching on the glass in areas of weaker and cooler areas such as where the globe gets pinched into a shaft or gas gets filled into the fixture than sealed off. Most often thru the shaft pinch a failure be it the little cone like areas of the globe that have a sharp edge to them in pinch or at the place that the electrode comes out of the pinch in being attacked by crusties and heat - often bad ballasts, voltage and or manufacturing problems.

    Still, once a lamp gets up to like 500 hours, it is either going to last an unknown amount of time or getting tired by way of snow like crusties forming on its globe or vapor like clouds especially forming around the outer axis of the lamps globe. The more vapor clouds, the more it seems like frost. The more the frost with some deposits or deposits mostly white alone, the more it seems like snow. Always white or silver, never yellow, green, brown, grey or black. See that or a lamp tint of them and you mostly have a gas escaping from the lamp somewhere situation. With them follow the rings in combination with colors of comtrails or rings plus silver clouds leading to a hole and you often the source of the failure.

    This at least for a Mac 2K like lamp, on a xenon lamp or even other types it could be a heat problem amongst other problems.

    Still I found a large sample of lamps that in their first fixtures that upon removal at 2,300 hours had of outer globe crusty appearance often were more clear or similar to that of lamps having 700 to say 1,300 hours of lamp life but not the first lamp in the fixture. This mostly of lamps in this range that were either snowball in totally covered over in crusties - less frequent or more just lamps with some snow, a bit of frost that was optically getting in the way, but a lamp for the most part was doing fine at least for a long term show. Somewhere between say 1,300 hours and 2,300 hours, if the lamp lasted that long and was in the original fixture, there was not any further damage to the lamp between those extent it seemed.

    Gross observation of course but observed that amongst a few hundred lamps so far observed, that those lamps installed as the first lamp for a at least Mac 2K or similar fixture where the lamp base did not give out due to possible operator error, that such lamps seemed to last over 3x their lamp life often and in those thousand hours in lamp life between 1,300 and 2,300 hours, there often amongst a volume - no doubt a lot of failures but not sufficient to throw out the observation, that lamps often not only last that long but seem to get no real further light blocking crusties and damage to the lamp than that. Certainly the buildup on the electrodes means a loss of luminous output in chemicals in the globe circulating, but as for the globe itself, they don’t seem to get worse for the most part as observation.

    Nor do they explode. Of the most recent few hundred lamps inspected, a few were exploded type. A few of them had something land on the globe that caused failure, most were due to fixture lamp socket failures, and a few were due to etching and or pinch failures, but most lived on. Very rare any lamp would take out a reflector or fail in any way more dangerous than the lamp taking out itself often in the outer pinch itself especially it the lead in wire/monofoil weld. This as opposed to other conditions. Sometimes that failure let the gas escape out of the globe but almost never was there real damage to the integrity of the globe. A few cracked globes but not often and this overall amongst lamps in all sorts of ages of fixtures.

    Voltage/ballast signatures. In the past I have noted that a lamp rejected from it’s first hour up thru like its 500th hour will for more short term shows once back in the shop or with picky designer would get rejected for being low in output, off color brown/green etc, screaming in making a noise, flickering or failing to strike. Yet in a second fixture they were installed in - especially if newer fixture, that lamp would often if nothing rally wrong with it in inspecting it, would work just fine in the second fixture, yet they most often wouldn’t live in being acceptable past like 500 to 750 hours in total accumulated lamp life. Almost never much past.

    Yet in same lamp type, there are these that lived up to 1,300 and even 2,300 hours in lamp life.

    What is it about a newer fixture and or its balast that allows for a lamp to last longer in life and or in switching lamps between fixtures of theoretically the same age, that lamp to work yet often not live past the rated expected lamp life of the lamp? Yet there is those lamps that at 2,300 hours in having survived past 1,300 hours look on the outside at least the same as a lamp that only worked that long in crusties often? Even had a few instances when out of spares that this show installed some 750hour and 1,000 hour lamps taken out of one fixture during a swap, re-install them into another fixture with a blown lamp and them be fine. This by way of inspecting some of the lamps especially in new fixtures that looked about like lamps that in crusties and buildups on the globe like lamps half their lamp life and did work fine in a second fixture at least for a few hundred more hours.

    A) new fixture, why do they seem to be able to run a lamp 3x past their expected lamp life to the ground at times without a problem in lamps removed from them don’t really seem much worse than lamps run at 50% past their lamp life if even that?

    B) is there any correction between lamp life and fixture/ballast age?

    C) why if given a globe is fairly clear, will a lamp that seemed low in output in one fixture, be often fine in another fixture if under say 500 hours, yet it mostly not live up to beyond like 750 hours even if in a new fixture as second install? This for the most part?

    Above questions for debate, agree and disagree as answers also. This granted I have photos of a lot of lamps and thousands of lamps I tracked and inspected so the observations I make should be fairly well substantiated as a norm with basis in finding at least for what I have observed.
     
  2. JD

    JD Well-Known Member

    Messages:
    4,028
    Likes Received:
    1,252
    Location:
    North Wales PA
    My own feelings are that the ballast age is the culprit independent of it being magnetic or electronic. (I have noticed the same thing in HPS and MH architectural lighting.)

    Theories - Electronic:
    The new ballast is designed & aligned to produce the correct current curve for the lamp, but as components age they change in value and this may upset the feedback loop making the ballast harder on the lamp. Some ballasts actually use potentiometers that may become noisy with age. Others use "select by test" resistors.

    Theories - Magnetic:
    Power factor caps (like all electrolytic) tend to drop in value with age or develop leakage. Also, in some cases, older cores may develop winding shorts. In a normal transformer, the core would fry in very short order, but a ballast core has a loose magnetic coupling and can actually operated with some forms of shorts. Remember, the pulse igniters used on these cores produce very high voltages which may breach the enamel insulation inside. I have had at least two cores where the current draw was higher than other cores of the same type when in operation. (~10%) This has to effect lamp life.

    Also, if the ignition circuit is weaker in one fixture, the lamp will appear to have a shorter life as it will be less likely to strike when old. I don't know of any studies on this, but I would suspect that as the parts age they may put out less voltage. (They contain a cap, a coil, and a high power diac)
     
  3. ship

    ship Senior Team Emeritus Premium Member

    Messages:
    6,173
    Likes Received:
    447
    Location:
    Illinois
    thanks, interesting concepts, perhaps in the end older ballasts should be changed as with older lamp bases for better fixture efficiency more often according to lamp hours this might show. Just a concept in lamp/fixture efficiency and thanks in helping me further a working concept.

    Still get amazed that the 2,300 hour lamps rated at 750 hours often look no worse than a 1,200 hour lamp and at times a 1,000 hour lamp look like output wise in the clouding of the globe, almost new at times. Not always of course but definately more based on fixture age the lamp was installed in than for other reasons I can see.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice