That's true. The lamps in question are GLC and FLK. They still "read" pretty white at 80%, and probably better color match the BTN lamps we have in the on-stage fresnels, anyway. This is not an ideal, or preferred solution. In our case it was the only feasible solution. We could have upgraded our ETC Sensor Pack to one with the Advanced Control Module, but that's not currently in the budget, and we still have an older Teatronics Genesis pack to contend with.
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Lights burning alot
- Thread starterthebikingtechie
- Start date
We have two dimmer packs, one a 24-channel ETC Sensor portable pack and one a 12-channel Teatronics Genesis pack.
I understand how SCRs work. You are correct, SCR dimmers work by switching on at some point during each half-cycle of the AC waveform. The SCR conducts for the remainder of the half-cycle, until the zero-crossing. The output voltage follows the input voltage, once triggered.
The voltage limiting feature of the ETC Sensor Advanced Control Module (that may not be the exact name) works by reading the effective RMS voltage at the dimmer output, and retarding the SCR trigger signal a bit later in the half-cycle if the output RMS voltage exceeds a preset threshold.
You can only really measure the output voltage of an SCR dimmer (except at 0 and 100) using a True RMS voltmeter. Standard AC voltmeters will be confused by the non-sinusoidal waveform, and provide inaccurate readings.
Incandescant lamps are sensitive to the RMS voltage value, not the peak voltage value. So, while the peak voltage on the output at 80% will indeed follow the input voltage, and the lamp will see a peak voltage greater than 115 volts, it doesn't matter. Removing "energy" by clipping each half-cycle to 80% brings the RMS voltage down to 115, and that's all that is required.
BTW, we determined the 80% number by measuring the True RMS voltage at the dimmer output and dimming down from 100 until the meter read 115 volts. Actually it was 80.6 or some such, but I've rounded it to 80% for ease of use.
Good thread I have stayed out of so far and good without me so far but seemingly locked into only a few of the potential problems or causes. A RMS meter will preform correctly as long as you have at least a 75w loading to your dimmer. It will go crazy if tested if not under load, but be more accurate once given that induced loading.
The lamp life concept was touched upon but not sufficiently. Lamp life in theory or concept is at the point where 50% of the lamps in 100 burn out after 10% of the premature ones are thrown out of the test sample. In other words, lamps blowing if all were installed at the same time means that all lamps are ready to blow at this point and some are on bonus time or dimmer/channel level extended time. Possible that them lamps are an example of all lamps in need to replace all time to replace all, rather than some form of the fixtures closer to the dimmer blow first type of example which would be uncommon but simply stated possible.
If it's random as to where and what fixture blows first, between distance from dimmer and what side of the stage it would be, than I would assume it to be an in general lamp issue. If more associated with one side of the stage or the ones closer to the dimmers than the others, one can meter and detect a voltage drop problem. If associated with a few select fixtures, than it's another problem by way of trim setting and or circuiting. If on the other hand random across the plot what blows now - really soon, it's time. Ensure your trim setting, your voltage and the house voltage and it's various spikes and drops, but still it's a wiring service thing as discussed as with voltage drop potentially which is less likely for me.
In the above you mention both GLC and FLK lamps. I assume a mixed inventory. Are the GLC lamps blowing at the same rate as the more fragile to focus and bump while hot, FLK lamps? One would assume a change over in from the FLK to the GLC in your inventory, does one assume than that the problem is with the newer GLC lamps blowing as quick as the FLK or that it's a at times a lamp will last forever than fail, and at times a lamp will fail soon? Are these the same colors or what in study of the problem is common to all by way of say all my persay, amber/white light blowing before the say cool versions of these lamps?
Very important, if say amber is normally on 80% and say cool blue or something balancing this is at 60%, it's less an issue of lamp life and more of cuing as obvious. If in use longer, or more, it would tend to fail first.
There is the use type stuff. Next beyond examining the lamp base is examining the fixture and lamp base of the lamp. A lamp will fail sooner if the fixture lamp base is trashed =- this no matter how much care one takes to the globe of the lamp. Your fixture lamp base trashed, it not only trashed the lamp but this base now trashes all future lamps installed within it. This at a premature rate or destroying.
What do the pins of your lamps look like once bad and removed? Do you inspect the lamp base to the fixture so as to ensure heat and contact surfaces are going to be clean or do you simply assume that installing a fresh lamp into a bad lamp base will correct the problem instead of add up to a brand new lamp that's going to be short on lamp life... again. Bad lamp base or something else bad = heat, your new lamp has less life.
Perhaps other stuff to look towards. Above is the mention of look at the bad lamps. This is key.
The lamp life concept was touched upon but not sufficiently. Lamp life in theory or concept is at the point where 50% of the lamps in 100 burn out after 10% of the premature ones are thrown out of the test sample. In other words, lamps blowing if all were installed at the same time means that all lamps are ready to blow at this point and some are on bonus time or dimmer/channel level extended time. Possible that them lamps are an example of all lamps in need to replace all time to replace all, rather than some form of the fixtures closer to the dimmer blow first type of example which would be uncommon but simply stated possible.
If it's random as to where and what fixture blows first, between distance from dimmer and what side of the stage it would be, than I would assume it to be an in general lamp issue. If more associated with one side of the stage or the ones closer to the dimmers than the others, one can meter and detect a voltage drop problem. If associated with a few select fixtures, than it's another problem by way of trim setting and or circuiting. If on the other hand random across the plot what blows now - really soon, it's time. Ensure your trim setting, your voltage and the house voltage and it's various spikes and drops, but still it's a wiring service thing as discussed as with voltage drop potentially which is less likely for me.
In the above you mention both GLC and FLK lamps. I assume a mixed inventory. Are the GLC lamps blowing at the same rate as the more fragile to focus and bump while hot, FLK lamps? One would assume a change over in from the FLK to the GLC in your inventory, does one assume than that the problem is with the newer GLC lamps blowing as quick as the FLK or that it's a at times a lamp will last forever than fail, and at times a lamp will fail soon? Are these the same colors or what in study of the problem is common to all by way of say all my persay, amber/white light blowing before the say cool versions of these lamps?
Very important, if say amber is normally on 80% and say cool blue or something balancing this is at 60%, it's less an issue of lamp life and more of cuing as obvious. If in use longer, or more, it would tend to fail first.
There is the use type stuff. Next beyond examining the lamp base is examining the fixture and lamp base of the lamp. A lamp will fail sooner if the fixture lamp base is trashed =- this no matter how much care one takes to the globe of the lamp. Your fixture lamp base trashed, it not only trashed the lamp but this base now trashes all future lamps installed within it. This at a premature rate or destroying.
What do the pins of your lamps look like once bad and removed? Do you inspect the lamp base to the fixture so as to ensure heat and contact surfaces are going to be clean or do you simply assume that installing a fresh lamp into a bad lamp base will correct the problem instead of add up to a brand new lamp that's going to be short on lamp life... again. Bad lamp base or something else bad = heat, your new lamp has less life.
Perhaps other stuff to look towards. Above is the mention of look at the bad lamps. This is key.
We have fewer instruments with FLKs; these being the Altman 360Q fixtures that we haven't yet converted to the new style reflector kit. I would have to say it was about equal on a percentage basis, but the majority were GLC. Both are very sensitive to shock and vibration when lit, especially at or near full intensity. We did investigate possible sources of mechanical vibration as the culprit, but didn't find anything conclusive.In the above you mention both GLC and FLK lamps. I assume a mixed inventory. Are the GLC lamps blowing at the same rate as the more fragile to focus and bump while hot, FLK lamps?
We took to dating the lamps when we replaced them (on the base). Most of the failed lamps had relatively few hours on them. We didn't have enough premature failures to do a really good stastical profile -- maybe a dozen total -- before we took corrective action by limiting ALL 115 V lamps to 80%.One would assume a change over in from the FLK to the GLC in your inventory, does one assume than that the problem is with the newer GLC lamps blowing as quick as the FLK or that it's a at times a lamp will last forever than fail, and at times a lamp will fail soon?
The premature failures caused by overvoltage have a "signature". The lamp envelope (quartz) is clean, and there are small and shiny balls of melted tungsten on the inside of the envelope. I spent a good bit of time talkaing to tech reps at ETC, Altman and Ushio about this problem. Everyone agreed that overvoltage is a real problem for 115 volt lamps. I was told that for every volt above 115 the rated life of the lamp is cut in half. I think this is probably an exaggeration, but it serves to illustrate the issue.
Not sure I follow you. The common feature seemed to be the nominal rated voltage of the lamps (115 vs, 120). We didn't see much difference, for example, between GLA and GLC lamps. The GLC lamps are the "long life" versions and have a slightly lower color temperature. The BTNs at 120 volts never give us problems.Are these the same colors or what in study of the problem is common to all by way of say all my persay, amber/white light blowing before the say cool versions of these lamps?
There used to be the Thorn HX-603 which was a 120v HX-600/FLK type lamp rated for 120v. Long gone but very much comperable and converted to the 115v long life GLA lamp by GE code I currently follow. Did you try GLA lamps for your inventory? Only so much doping of the filament one can do before in some basic sense, a long life 115v lamp is more like a 120v high output lamp than that of something that's going to live forever. The note of yoru Fresnels not acting this way is valid. An old theater of mind did EHG lamps for their shin busters constantly kicked by dancers. Perhaps that would be a solution if all else still fails with vibration. Have various listings of a FLK or HX-603 that was 120v but such a lamp no longer exists. Perhaps Thorn by way of Nelson Lamps distributing them is still doing the 120v HX-603 and it would be your solution. Don't know, the 115v GLA lamp has been suitible for my usage in being resistant sufficiently.
What I mean in the latter section of reply is more about your plot in useage of the lamps. Given even say two colors of gel in use, not all fixtures will have the same amount of corrected lamp hours of usage. Say fixtures that commonly have blue gels in them might as a concept be expected to have less a lamp life than lamps that commonly have say a straw gel in front of them. Consider the blue in even low output is helping light a day scene but the straw is for the most part gone in a night scene. Just a sort of say "straw theory" but given the extent of your study, something to consider in looking at.
Very impressive the study into this you have done so far... sounds like in also studying problems with lamps at times - for me at the moment it's wee slight cracks in the pinches of Mac 700 lamps.
Don't need the new reflector kit to convert the lamp as per above answer but it confirms the mixed inventory and conversion in the process worndering. The old reflector/base will work as long as it lasts more efficiently with the newer grade of lamp in place of the FLK. The GLC will probably even be cooler on it to some small percentage. None the less, if your old fixtures do a FLK, they will take the better GLC without a problem. Stop buying the FLK if reflector kits is all that's holding you up. Give a try to the Osram HPR 575/115v lamp also for a play test. Very good alternative to the GLC as an alternative to give a play test to in seeing what you think of it. Very much different beam of light as a theory and one that would or could be useful to have a look at.
Interesting and I will note the note you have of the GLC having similar to FLK shock problems. I'm aware of FLK lamps being more shock problematic than say a EHG, but thought that the GLA/GLC line of lamp had shock resistance as one of their featured improvements. Further study into this might be very useful if you have time. Try different brands also in all lamps having different technologies to the same ANSI lamp at times coming to play.
Dating of lamps - now there is an organized person. These days I spend more time tracking lamps than wiring gear. Just broke 10,000 lamps tracked on the computer today as a sort of event like rolling over one's car. Dated incandescent lamps helps lots for inventory, study and replacement reasons - in general if for reason of replacement if it died before the rated hours, you have a clame and a date on the lamp helps say when that "begin" date was. This in addition to helping with lot numbers of the various lamps in your inventory. Nice... what do you date them with graphite pencil?
Yep, over voltage is a real problem when one needs to use high output lamps over that of long life lamps. Here is what I live with:
v = Volts - A measurement of the electromotive force in an electrical circuit or device expressed in volts. Voltage can be thought of as being analogous to the pressure in a waterline. The effect of voltage on a lamp will cause a significant change in lamp performance. For any particular lamp, light output varies by a factor of 3.6 times and life varies inversely by a factor of 12 times any percentage variation in supply. For every 1% change in supply voltage light output will rise by 3.6% and lamp life will be reduced by 12%. This applies to both DC and AC current. Most standard line voltage lamps are offered at 130v. Since most line voltage power is applied at 120volts, the result is a slight under voltaging of the filament. The effect of this is substantially enhanced lifehours, protection from voltage spikes and energy cost savings. - GE Spectrum Catalog ???
Voltage and Light Output: The effect of voltage on the light output of a lamp is ±1% voltage over the rated amount stamped on the lamp, gives 3.1/2% more light or Lumens output but decreases the life by 13% and vise a versa.
Do not operate quartz Projection lamps at over 110% of their design voltage as rupture might occur. GE Projection, Ibid p.13
A 5% change in the voltage applied to the lamp results in
-Halving or doubling the lamp life
-a 15% change in luminous flux
-an 8% change in power
-a 3% change in current
-a 2% change in color temperature (0.4% change per1% voltage.)
Osram Technology and Application Tungsten halogen Low Voltage Lamps Photo Optics, p.21
More study and read the above Osram free PDF that is linked to in most all their halogen ANSI lamps. Good book on studying further into one's lamps. AT this point, it's probably the next step in figuring out this problem.
What I mean in the latter section of reply is more about your plot in useage of the lamps. Given even say two colors of gel in use, not all fixtures will have the same amount of corrected lamp hours of usage. Say fixtures that commonly have blue gels in them might as a concept be expected to have less a lamp life than lamps that commonly have say a straw gel in front of them. Consider the blue in even low output is helping light a day scene but the straw is for the most part gone in a night scene. Just a sort of say "straw theory" but given the extent of your study, something to consider in looking at.
Very impressive the study into this you have done so far... sounds like in also studying problems with lamps at times - for me at the moment it's wee slight cracks in the pinches of Mac 700 lamps.
Don't need the new reflector kit to convert the lamp as per above answer but it confirms the mixed inventory and conversion in the process worndering. The old reflector/base will work as long as it lasts more efficiently with the newer grade of lamp in place of the FLK. The GLC will probably even be cooler on it to some small percentage. None the less, if your old fixtures do a FLK, they will take the better GLC without a problem. Stop buying the FLK if reflector kits is all that's holding you up. Give a try to the Osram HPR 575/115v lamp also for a play test. Very good alternative to the GLC as an alternative to give a play test to in seeing what you think of it. Very much different beam of light as a theory and one that would or could be useful to have a look at.
Interesting and I will note the note you have of the GLC having similar to FLK shock problems. I'm aware of FLK lamps being more shock problematic than say a EHG, but thought that the GLA/GLC line of lamp had shock resistance as one of their featured improvements. Further study into this might be very useful if you have time. Try different brands also in all lamps having different technologies to the same ANSI lamp at times coming to play.
Dating of lamps - now there is an organized person. These days I spend more time tracking lamps than wiring gear. Just broke 10,000 lamps tracked on the computer today as a sort of event like rolling over one's car. Dated incandescent lamps helps lots for inventory, study and replacement reasons - in general if for reason of replacement if it died before the rated hours, you have a clame and a date on the lamp helps say when that "begin" date was. This in addition to helping with lot numbers of the various lamps in your inventory. Nice... what do you date them with graphite pencil?
Yep, over voltage is a real problem when one needs to use high output lamps over that of long life lamps. Here is what I live with:
v = Volts - A measurement of the electromotive force in an electrical circuit or device expressed in volts. Voltage can be thought of as being analogous to the pressure in a waterline. The effect of voltage on a lamp will cause a significant change in lamp performance. For any particular lamp, light output varies by a factor of 3.6 times and life varies inversely by a factor of 12 times any percentage variation in supply. For every 1% change in supply voltage light output will rise by 3.6% and lamp life will be reduced by 12%. This applies to both DC and AC current. Most standard line voltage lamps are offered at 130v. Since most line voltage power is applied at 120volts, the result is a slight under voltaging of the filament. The effect of this is substantially enhanced lifehours, protection from voltage spikes and energy cost savings. - GE Spectrum Catalog ???
Voltage and Light Output: The effect of voltage on the light output of a lamp is ±1% voltage over the rated amount stamped on the lamp, gives 3.1/2% more light or Lumens output but decreases the life by 13% and vise a versa.
Do not operate quartz Projection lamps at over 110% of their design voltage as rupture might occur. GE Projection, Ibid p.13
A 5% change in the voltage applied to the lamp results in
-Halving or doubling the lamp life
-a 15% change in luminous flux
-an 8% change in power
-a 3% change in current
-a 2% change in color temperature (0.4% change per1% voltage.)
Osram Technology and Application Tungsten halogen Low Voltage Lamps Photo Optics, p.21
More study and read the above Osram free PDF that is linked to in most all their halogen ANSI lamps. Good book on studying further into one's lamps. AT this point, it's probably the next step in figuring out this problem.
Ah, now I understand. We only have GLC/GLA lamps in the FOH (Box Boom) positions, which in the repertory plot are gel'ed with light warms (LUX 02, 05) and medium blues (LUX 65, 68). These tend to be used at full or near full most time for most of the shows in our venue. We have Altman 65Q Fresnels with BTNs and Altman 360Q 6x9s with FLKs on the electrics battens.What I mean in the latter section of reply is more about your plot in useage of the lamps. Given even say two colors of gel in use, not all fixtures will have the same amount of corrected lamp hours of usage. Say fixtures that commonly have blue gels in them might as a concept be expected to have less a lamp life than lamps that commonly have say a straw gel in front of them. Consider the blue in even low output is helping light a day scene but the straw is for the most part gone in a night scene. Just a sort of say "straw theory" but given the extent of your study, something to consider in looking at.
We could certainly give that a try. Altman definitely recommends using FLK with the old reflectors and GLA/GLC with the new reflectors. I think the difference is in the filament geometry. Part of the success of the S4 is the optics, but part is the lamp design. The higher, whiter output of the HPL style lamps is one part. The compactness of the filament is another. The FLK, like the EHG and FEL before it, has a relatively long, coiled-coil filament. The GLA/GLC and HPL series lamps come closer to approximating a "point-source". The physics of an ellipsiod are that light rays emanating from a point coincident with one foci will re-converge in a point at the other foci. The center of the lamp fillament goes at one foci. That's why the LCL measurement is important. To the extent that lamp filaments have actual dimensions and are _not_ a point source, the optics represent a compromise. I think that's why the new reflectors are considered a match for the HPL style filaments of the GLA/GLC.Don't need the new reflector kit to convert the lamp as per above answer but it confirms the mixed inventory and conversion in the process worndering. The old reflector/base will work as long as it lasts more efficiently with the newer grade of lamp in place of the FLK. The GLC will probably even be cooler on it to some small percentage. None the less, if your old fixtures do a FLK, they will take the better GLC without a problem. Stop buying the FLK if reflector kits is all that's holding you up.
Yep, I've once or twice pulled the classic bone-head maneuver of manhandling an instrument during focus that is "stuck" only to have the GLA/GLC immediately pop for my efforts. Duh-Oh!Interesting and I will note the note you have of the GLC having similar to FLK shock problems.
Well, to be honest, now that the problem seems to have been solved, we don't do this anymore. Probably should though...Dating of lamps - now there is an organized person.
Pencil on the white cermaic bases, Sharpie on the aluminum bases....what do you date them with graphite pencil?
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