Lots of light bulbs going out
Lots of light bulbs going out
(OP)
I seem to have an inordinate number of light bulbs going out at my house. It seems like 5 or 6 have gone out in the last few weeks. I've only been in the house for a few months, so I don't have any history. The bulbs are all in recessed cans and are mostly 65W indoor flood bulbs.
Is this just a weird coincidence or do I have some strange power quality problem?
Any thoughts?
Is this just a weird coincidence or do I have some strange power quality problem?
Any thoughts?






RE: Lots of light bulbs going out
2) The recessed cans are the type that cannot have thermal insulation touching them, but they do. This overheats the bulbs and shortens their life. Eventually your house may burn down and you won't have to worry about the bulbs.
3. You have excessively high voltage, > 125-130 volts.
RE: Lots of light bulbs going out
RE: Lots of light bulbs going out
In the part of the Country where I live the utilities set the voltage at 125 VAC.
Most light bulbs I've seen in stores are rated at 120 VAC.
I went to an electrical supply store and ordered bulbs rated for 130 V, to "handle" our higher (125) voltage.
I have since noted the lightbulbs lasting much longer, since they are getting hammered by overvoltage.
Also, bulb manufactures have a rough-service bulbs with a 130V rated.
RE: Lots of light bulbs going out
RE: Lots of light bulbs going out
RE: Lots of light bulbs going out
The high voltage mentioned by others is by far the most common cause, however.
respectfully
RE: Lots of light bulbs going out
Is suspect by now somewhere on the web there is a site evaluating the different brands.
Replace as many as you can with compact floruscent bulbs, they are cheaper.
RE: Lots of light bulbs going out
My lighting costs sky rocketed about the time I was stoopid enough to use compact fluorescent bulbs. I have never had one last even a year!! So all their claims of "look how this overpriced bulb of ours will save you a fortune over it's 7 year life" are a load-oh-cr@p as far as I'm concerned.
A dimmer switch could possibly help a lot.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Lots of light bulbs going out
RE: Lots of light bulbs going out
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Lots of light bulbs going out
The life of an incandescent bulb is a function of the voltage.
Life of bulb = (Design voltage/Actual voltage)12 X Life at design voltage
That y12 means things change very fast !
Example: 120V bulb used at 125V
Life = (120/125)12 X 1200 hrs
= 735 hrs
Raising the voltage 5 volts above design voltage cuts the bulb life in half!!
Likewise a 120V bulb used at 115V
Life = (120/115)12X 1200 hrs
= 2,000 hrs a big increase.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Lots of light bulbs going out
RE: Lots of light bulbs going out
Compact fluorescents have EVERYTHING to do with brand and cost. The very real benefits and rebates from utilities make for a choice market in which the purveyors of cheap junk can thrive. Unfortunately many of the big-box home improvement stores have buyers with absolutely no real-world experience, so they get sucked in just like everyone else. Notice too that I said cost not sell price, because unfortunately the worst offenders have also figured out that if they raise the price on their junk, it will be percieved as being better quality!
The answer is to read reviews of specific brands from people like Consumer Reports. They make very good assessments of quality and longevity. I bought several brands of cr@p as well, but after doing my own due dillegence I now have CFLs that have been installed for over 7 years.
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: Lots of light bulbs going out
RE: Lots of light bulbs going out
jraef; What brand have you had the best luck with?
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Lots of light bulbs going out
RE: Lots of light bulbs going out
I never buy anything w/o checking with Consumer Reports.
RE: Lots of light bulbs going out
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RE: Lots of light bulbs going out
It's not about renting or owning, it's about the rules of this forum (not mine). By "homeowner" I meant not related to a professional engineering issue, the charter of this forum. I didn't RF this thread, but I think the admins eventually might. That's all I was saying.
Back to you original issue, another approach is to find some little discs called "Bulb Savers" at the hardware store. Cooper Electric Bulb Saver link They are sold to save energy but they also make your bulbs last 100 times longer (no joke). They are a diode that goes into the lamp socket before screwing in the bulb. They make the bulb work on 1/2 wave AC, but other than a reduced lumen output you would never know. Human eyes can't pick up strobing higher than about 16Hz, so at 30Hz (effectively) you don't notice any flicker. The trick around the reduced lumen output is to increase the wattage of the lamp. That defeats the energy savings of course, but 100 times the lamp life is worth the effort, especially if the lamp is in a hard to reach area. These things have fallen out of favor since the advent of CFLs but I still see them around in places.
Kieth,
The funny thing is, I can't tell you! It's been so long now I'll have to go remove one and read the name off of it. I do know that "Lights of America" is some of the cheapest cr@p out there IMHO. Some of those didn't even last 3 months.
I have some here in my office from Techna Bright bought at Costco, but they are only about 2 years old so the jury is still out on them. I installed some other brand based on Consumer Report's recommendation on my front porch fixture when I moved here in Oct. 1997 and I know I bought them all at the same time. Some already died, but they were burning base up which isn't too good for CFLs because the electronic ballast heats up. The porch light is base down, 9 years and counting, with timer operation so it burns every day for 10 hours (roughly). The only drawback is the warm up time. I'll get the name and post it tomorrow.
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: Lots of light bulbs going out
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RE: Lots of light bulbs going out
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RE: Lots of light bulbs going out
RE: Lots of light bulbs going out
Then the temperature is some power of a power.
Then there is some tungsten in a vacuum evaporation curve that is probably a power owing to Area so you end up with a bunch of powers X powers of powers. <just my guess>
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Lots of light bulbs going out
What I meant was the bulb filament is only getting power to it 30 times per second instead of 60. With a sensitive enough light meter connected to a scope I have seen the flicker and it looks like 30Hz. My old analog light meter doesn't see it though, the movement is probably too slow to pick it up.
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: Lots of light bulbs going out
I did try "Lights of America". True garbage of the lowest quality. None lasted more than two months.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Lots of light bulbs going out
I wonder if it is the steady state condition or the inrush that limits life?
60hz sinusoidal current has 60 positive peaks and 60 negative peaks per second. If you get rid of 60 negative peaks per second, you still have 60 positive peaks per second.
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RE: Lots of light bulbs going out
Some premium bulbs had longer lifetimes, but not enough longer to justify the higher price. Some premium bulbs are just high priced.
Mike Halloran
Pembroke Pines, FL, USA
RE: Lots of light bulbs going out
ko (www.ecooling.biz)
RE: Lots of light bulbs going out
By the way the longest burning light bulb in the world is just down the street <sorta> actually closer to jraef than me. It has been burning for 105 years continuously. In a Livermore firehouse. It's so old it is a carbon filament bulb. It's 4 watts. And lights the fire truck bay. It was hand made and is likely built as a 150V bulb or something and it is making great use of the y12.
Math test anybody?
Following the equation above:
And using the assumptions;
1) Actual Voltage = 120V
2) Life at design voltage = 1200 hrs
3) Actual life 110 years
Life of bulb = (Design voltage/Actual voltage)12 X Life at design voltage
What was the design voltage?
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Lots of light bulbs going out
It brings to my mind an approximation.
Let's say resistance varies with temperautre
R = R0*(T/T0)^n where n>0
HeatIn=V^2 / [R0*(T/T0)^n]
HeatOut = T^4 (approximate that Tair is much smaller and that other energy loss mechanisms are insignificant compared to the radiation).
Equilibrium temperature occurs where HeatIn = HeatOut.
T4 = V^2 / [R0*(T/T0)^n]
multiply each side by T^n
T^(4+n) = V^2 / [R0*(1/T0)^n]
Raise each side to the power 1/(4+n)
T = V^2/(4+n) * [R0*(1/T0)^n]^1/(4+n)
Note the stuff on the right is all constant with respect to T and V. Remove it and change = to ~
T ~ V^2/(4+n)
Since n>1, this is less than V^0.5, i.e. T varies as less than the square root of V.
jraef - did you see my comment above?
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RE: Lots of light bulbs going out
The wave shape on luminosity from the scope threw me off course though because it looked like 30Hz. Can't think of why in light of your clarification, maybe measurement error or response delay in the filament. I was letting my observation cloud my reasoning. Dangerous thought process.
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: Lots of light bulbs going out
ko (www.ecooling.biz)
RE: Lots of light bulbs going out
Get a voltmeter and check your voltage leg to ground. Turn on a heavy 120 volt load (like a microwave oven)on the other leg and see if your voltage goes up. If it does, go check your neutral connections.
RE: Lots of light bulbs going out
I was half expecting to have 8 extra CFL's to find a home for but they actually exceeded my expectations. At the time, they were selling for $12/4 with a $5 mail in rebate.
RE: Lots of light bulbs going out
Regular filament bulbs do not exhibit this problem.
I also use the compact flourescent bulbs in my house, but for my reading lights, I use the filament bulbs (130 V).
I've noticed that when the compact flourescent bulbs run continuously, they burn out quickly. If you want 'em to last long, you have to make certain they do not operate 24/7.
RE: Lots of light bulbs going out
RE: Lots of light bulbs going out
SphincterBoy; I'm with you on that! I read at least an hour a night (SciFi) and dimmable tungsten is the only way to go for the color and the lack of flicker.
BronYrAur; We're getting a lot of mileage out of your question!!
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Lots of light bulbs going out
In Europe the best CFL's I've found for longevity are made by Philips. I've used them in the exterior lighting at home with better life than I got from GE and some of the anonymous types out there. I'm not sure how much of the improvement is related to our climate - England is pretty damp, so perhaps the Philips design is better suited to it. I'm also suspicious of low amplitude vibration of the luminaire caused by wind. I'm certain this contributes to the premature demise of the tungsten filament lamps, but I wonder if some CFL cathodes are also susceptible to this failure mode.
Aside: I keep receipts for the mains voltage halogen lamps bceause they're expensive, and if they don't make it past 6 months I take 'em back. I've never been refused a refund!
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I don't suffer from insanity. I enjoy it...
RE: Lots of light bulbs going out
The one in my porch light fixture that has been operating for 7 years or so is a Phillips EL/O 18, 18W Outdoor rated. it's only rated officially for 10,000hrs, but I must have more than that by now.
RE: Lots of light bulbs going out
Scotty; I set up an entire system for returns.. keeping the blister packs, labeling, the bulbs, and the receipts, to return the failures. That got labor intensive.
Let the testing begin!
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Lots of light bulbs going out
RE: Lots of light bulbs going out
I will pick up some GEs too (imagination at work). I like the quiet!
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com