Premature Failure of Incandescent Lamps

Status
Not open for further replies.
T

terryminer

Member
We have a new office type installation that is experiencing premature incandescent lamp failures. Some background: Recessed 120V reflector trim incandescent cans, 150w R30 flood rated, non-IC and clear of any nearby materials. We've measured voltage at 119-121V, current is 10amps on the 20amp circuit, and grounding seems clear. We had the utility company record with a power meter without abnormality identification. The lamps are burning out with only +/- 200 hours of use. Lamp manufacturer says voltage spikes, and utility says they are clear. No one seems to be able to find incorrect installation or incoming power problems with certainty. I've suggested putting a recording power meter on the system for a month to watch incoming power characteristics. What could it be and where could the problems be originating from? Any Ideas?
 
Re: Premature Failure of Incandescent Lamps

What is the voltage rating of the lamps and are they a nationally recognized lamp? IE not some offshore brand?
 
Re: Premature Failure of Incandescent Lamps

Lamps are US brand and rated for 120V. We've also tried 130V rated lamps without additional success.
 
Re: Premature Failure of Incandescent Lamps

I definitely would stay with the 130 volt rating lamp. I would also do as you suggested, and that is to install a power monitor that would measure the voltage and the amperage at a very fast rate.
We have had to do that many times to find a voltage spike problem and/or a amperage problem. The type of monitor that I am speaking of is one that is very fast acting and would hold it in memory the time, date, and all other pertinent information.
 
Re: Premature Failure of Incandescent Lamps

I was discussing this very question just the other day and was directed to a GE FAQ that says the most likely cause is the fixture.

I had, and have, a hard time thinking that the fixture is the culprit, especially in your case, terryminer as your installation is new and, presumably, contains many luminaires all exhibiting the same malady.

But, there it is, for what its worth.
 
Re: Premature Failure of Incandescent Lamps

Al:

I don't see anything in the GE document that explains why bulbs burn out too fast. It all looks like a sales pitch for their higher cost lamps (and I am skeptical that those would last any longer. 2 years at 4 hours per day is still only 3000 hours, and how would you prove how long you had it on).

I would love to see some independent testing for lamp life. I think manufacturers test and rate their own bulbs.

I also think one company in paticular (this is just an opinion, and I'm not naming the company) has managed to almost monopolize the consumer market by getting their bulbs in most of the chain and grocery stores. Then they realized that shorter bulb life meant higher sales and more profits.

So if you aren't happy with the "Spacely Sprockets" brand, try the "Cogswell Coggs" brand :D
 
Re: Premature Failure of Incandescent Lamps

Does the building vibrate? Say from some AC equipment or whatever. The TI Semiconductor Bldg. in Dallas with its unique construction was infamous for its vibration. Could not use the top floor for certain delicate operations.
 
Re: Premature Failure of Incandescent Lamps

Yep, I worked for TI from 1960-71, then went to MOSTEK from 1971-82.
 
Re: Premature Failure of Incandescent Lamps

I believe rattus makes a good point-- it's worth investigation. The coiled-coil filaments of incandescent lamps are delicate and susceptible to jarring and vibration, especially when the lamps are on. Jarring can force adjacent loops of a coiled filament to come into contact creating shorts that reduce lamp life.

If the office has an occupied floor above, or the fixtures are subjected to vibrations as rattus explained, then it's worth taking a look to see if the mounting environment is a contributing factor in the short lamp life. If so, then a step towards remedying the problem may be to do as electricmanscott suggested-- use lamps rated for 130-volts because these lamps are often rated for rough-service as well.

This is just an opinion... I could be wrong! Check with the lamp manufacturer.

"Give me a set of golf clubs and a beautiful woman... and you can keep the golf clubs!" :cool: (read it somewhere).
 
Re: Premature Failure of Incandescent Lamps

try some rough service bulbs first.

i have noticed in the last few that most bulbs are more sensitive, and extremely sensitive when hot.

my fluke 87 has a good high/low setting that allows recording of each new high or low.

paul
 
Re: Premature Failure of Incandescent Lamps

I'm going take the stupid cave man approach.

I think it's rediculous to have to invest so much valuable mental energy to solve a problem like this.

10 years ago (at least in my recolection) this didn't happen.

Lightbulb manufacturers seem to be excelling in the area of getting their customers to replace their bulbs more and more often. Hey why not daily basis?

I guess it's possible that this is somehow the fault of the building owner or the electrical contractor or the mail man.

Noise spikes indeed.

How many scientists does it take to get a light bulb that works?


Edit: I want to know how much hotter the filiment will get in a couple nanoseconds. On second thought no I don't.

[ December 24, 2004, 12:09 PM: Message edited by: physis ]
 
Re: Premature Failure of Incandescent Lamps

WHEEW WHEE, yur jus a yungin.

Rattus, in my OEM days we had a circuit that used I think a 3900 quad op amp (or something), we didn't force this thing past the envelope and I don't remember the details. But if we put a TI component in it it wouldnt work. Anybody elses was fine. Did you work on that product? :D
 
Re: Premature Failure of Incandescent Lamps

I have a friend that has a double major in physics and metallurgy. While he was completing his PhD in this double major, he explained that the tungsten filament shears on an atomic level. . .

The filament, when hot and emitting light, is already dancing wildly between its supports. Over time, under these extreme conditions, the tungsten will shear, the atoms will slip along a plane, and re-stabilize.

When the slip occurs at a right angle to the length of the wire, the wire, in effect, gets thinner, and at that thinner point is going to get hotter, and in turn be more prone to another shear.

With EPACT's mandated energy saving, it seems to me, manufacturers are pushing the filament into higher temp ranges to gain a higher lumen output. This higher temp sets the filament up to fail faster.
 
Re: Premature Failure of Incandescent Lamps

Are they still using tungsten Al? There's a lot of Ni-Chrome going into element type stuff now-a-days.

I can definately beleive that there might be some all wise, appointed, instead of elected, agency dictator behind the whole thing. After all, wasted money is good for the economy because as long as money changes hands the government profits.
 
Re: Premature Failure of Incandescent Lamps

Sam,

I'd have to check back with Half (my friend). As I recall the conversation, it was about incandescent bulb filaments, not the metal, specifically. . .In my head I think "tungsten".

It's been awhile since I got ahold of him, let me see if I can catch up to him.
 
Re: Premature Failure of Incandescent Lamps

I don't really know the atomic or molecular details but I think the atomic level "sliding" or fracturing is what's driving the replacement of tungsten with Ni-Chrome. Again, I don't know but isn't Ni-Chrome more expensive?
 
Status
Not open for further replies.
Top