Erratic fluourescent tubes

[RhinoCan]

My mother has a problem with some of her fluorescent tubes in her basement. I was hoping I could get some advice here.

She has a variety of 48 inch fluorescent tubes in her basement to light the unfinished part of the basement, which is mostly used for laundry and storage. Some of these fluorescents regularly stop working. For instance, I found three different tubes that seemed dead when I was there the other day. In two of the cases, I got them working again by rotating them in the socket until they lit up. In the third case, it flickered a bit but wouldn't light up so I replaced that one and the new tube worked fine.

Can anyone suggest why the fluorescents are winking out and why rotating them in their sockets "fixes" the problem, at least for a while? Is the ballast resistor a factor in this problem? Do they need to be replaced periodically as a routine maintenance thing?

I really don't know much about fluorescent lights so I'm hoping someone here can educate me a bit or send me to a more appropriate forum since this seems a bit out of your normal subject matter.

 

[kak111]

I hope these help you.............

How Fluorescent Lamps Work
HowStuffWorks "How Fluorescent Lamps Work"

fluorescent lamp or fluorescent tube
https://en.wikipedia.org/wiki/Fluorescent_lamp

how a fluorescent light works
**broken link removed**

 

[ark5230]

Fluorescent tubes have shelf life. After some time, due to diffusion of gases (the tube light has vacuum and vapour) the composition goes bad and the lights function erratically or fail and thus need replacement. In addition to shelf life, because of the filament inside and metal vapour, it has working life too, after which it needs replacement.
So far as the rotating the tube is concerned, at time on long standing a thin film of oxides develop on metal surface or due to dust and dirt the electrical contacts go bad, or even due to vibration or jerks at times the contacts get dislocated, in such cases rotating the fluorescent tubes a little helps to refresh the contact and thus the fluorescent tubes starts working again. This is a simple description of the details explaining the issue in simple words.

 

[goldsmith]

check your start and choke

 

[RhinoCan]

Fluorescent tubes have shelf life. After some time, due to diffusion of gases (the tube light has vacuum and vapour) the composition goes bad and the lights function erratically or fail and thus need replacement. In addition to shelf life, because of the filament inside and metal vapour, it has working life too, after which it needs replacement.
So far as the rotating the tube is concerned, at time on long standing a thin film of oxides develop on metal surface or due to dust and dirt the electrical contacts go bad, or even due to vibration or jerks at times the contacts get dislocated, in such cases rotating the fluorescent tubes a little helps to refresh the contact and thus the fluorescent tubes starts working again. This is a simple description of the details explaining the issue in simple words.

Thanks very much for your reply to my question.

I know you dumbed it down a bit but that was exactly the right thing to do in my case. I'm not actually dumb but I forget my high school and first year university physics because that was a long time ago ;-)

The bottom line is that rotating the tube gives me a little extra time to acquire new fluorescent tubes but I really need to replace the tubes due to the limited life of the tubes themselves, not because of any electrical problem with the lighting fixture itself. Correct me if I'm wrong....

---------- Post added at 16:53 ---------- Previous post was at 16:38 ----------

You're kidding right? Those are car parts and have nothing to do with fluorescent tubes in a house

On the off chance that you're serious, I went through the articles cited by kak111 but I didn't see anything about a choke being part of a fluorescent tube design and only old-style fluourescent tubes apparently have starters.

---------- Post added at 17:00 ---------- Previous post was at 16:53 ----------

Thank you for the links!

I went through the articles at the first and second links you provided. The third link was dead.

 

[pranam77]

Ok..as i guess, the tubes are fitted in a basement and normally this place will have moisture than others. Here the connectors tend to corrode more fast and this is what i guess is happening with your tubes. Try to solder the ends or get some one to solder it. If its a flickering problem, usually the problem is with the starter but still it has a holder whose contacts will be rusted. You may temporaryly solve these problems by spraying WD40 or any such mositure removal sprays too.
Cheers

 

[Raza]

Hi,
In the basement normally the moisture is on higher level as compared to the normal rooms on the ground or upper floors. And specially when the laundry is there in the basement the moisture level increases to higher level as compared to a place without water work. The moisture causes OXIDATION on the Tube pins and the contacts go bad or POOR. This situation causes the Tubes to show erratic behavior.
As the Fluorescent Tubes need about 300 volts to start the glowing but the Oxidation on the contact cause a leakage current out side the tube hence the tube stops working. The best solution is Scheduled or a Fixed Time duration maintenance of the Tube holders and the tube pins. You can use WD-40 (as said by pranam77) to displace the water vapors and moisture. This will definitely reduce problem to a considerable level.

 

[RhinoCan]

Ok..as i guess, the tubes are fitted in a basement and normally this place will have moisture than others. Here the connectors tend to corrode more fast and this is what i guess is happening with your tubes. Try to solder the ends or get some one to solder it. If its a flickering problem, usually the problem is with the starter but still it has a holder whose contacts will be rusted. You may temporaryly solve these problems by spraying WD40 or any such mositure removal sprays too.
Cheers

I don't understand what you are suggesting. I understand your point about moisture and you have guessed correctly that these tubes are mounted to the joists in an unfinished portion of the basement. But what is it that you want me to solder? I can solder but I'm not sure what I'm supposed to solder. Am I supposed to solder the pins of the tubes into the sockets? Wouldn't that make it very difficult to change the tubes again when the tubes finally stop working altogether? I can have a look at the starter holder too and see if the contacts are rusty, then clean that off as well as I can.

---------- Post added at 17:03 ---------- Previous post was at 17:00 ----------

Hi,
In the basement normally the moisture is on higher level as compared to the normal rooms on the ground or upper floors. And specially when the laundry is there in the basement the moisture level increases to higher level as compared to a place without water work. The moisture causes OXIDATION on the Tube pins and the contacts go bad or POOR. This situation causes the Tubes to show erratic behavior.
As the Fluorescent Tubes need about 300 volts to start the glowing but the Oxidation on the contact cause a leakage current out side the tube hence the tube stops working. The best solution is Scheduled or a Fixed Time duration maintenance of the Tube holders and the tube pins. You can use WD-40 (as said by pranam77) to displace the water vapors and moisture. This will definitely reduce problem to a considerable level.

When doing the Scheduled or Fixed Time mantainance, are you suggesting that this maintenance would consist entirely of using WD-40 on the pins and tube holders? Or are you implying some other form of maintenance like trying to sand off rust or use liquid rust remover?

 

[Audioguru]

The light over my workbench is a Chinese fluorescent fixture with two 48" 40W tubes. They frequently flicker. The ballast is an inductor and transformer that is made in America and is labelled "68 degrees F or higher". My basement is cooler than 68 degrees F but the tubes work fine at temperatures above 68 degrees F.

I bet I paid for that heavy ballast to travel completely around the world but the parts of the light are free.

 

[RhinoCan]

The light over my workbench is a Chinese fluorescent fixture with two 48" 40W tubes. They frequently flicker. The ballast is an inductor and transformer that is made in America and is labelled "68 degrees F or higher". My basement is cooler than 68 degrees F but the tubes work fine at temperatures above 68 degrees F.

I bet I paid for that heavy ballast to travel completely around the world but the parts of the light are free.

I hadn't even thought of temperature as a factor. I must look at the tubes the next time I'm at my mother's house and see what temperatures they are supposed to run in. It's entirely possible that the room is colder than the rated temperatures for the tubes, in which case our next batch of tubes should be designed for slightly cooler temperatures. I don't imagine her basement gets very cold but it might well be less than 68 F....

Thanks for the suggestion.

 

[Audioguru]

I hadn't even thought of temperature as a factor. I must look at the tubes the next time I'm at my mother's house and see what temperatures they are supposed to run in. It's entirely possible that the room is colder than the rated temperatures for the tubes, in which case our next batch of tubes should be designed for slightly cooler temperatures. I don't imagine her basement gets very cold but it might well be less than 68 F....

Thanks for the suggestion.

It was the BALLAST inductor with the minimum temperature rating, not the tubes. The tubes must use a higher starting voltage when they are VERY cold.

 

[pranam77]

Yes..as a final option i suggested you to solder the pins of the tube to the wires which are now connected to the holder which may be troublesome now. When you solder the problems if was with poor contacts, will vanish and the tube should last long than you get it now. Thus soldering next tube may be after 3-4 years+ shouldnt be a problem. Anyways, using WD40 to drive out moisture or using connectors with brass contacts will too works well if you dont prefer soldering.

 

[Raza]

RhinoCan,
Soldering the wires is best easy and longer lasting solution (if you can). you have to use WD-40 (may be half yearly), but that is in case of the default built connectors.

 

[RhinoCan]

It was the BALLAST inductor with the minimum temperature rating, not the tubes. The tubes must use a higher starting voltage when they are VERY cold.

Sorry, I misread your initial remarks on the temperature. If my ballast inductor is rated for higher temperatures than they get in the basement, I will see if there are other ballasts that will work better in cooler temperatures.

 

[ark5230]

Regularly used ballasts are simple inductors where copper / aluminum wire is wound on iron lamination, such ballasts are not expected to be that sensitive to temperature, however, newer ballasts that are electronic could depend on temperature!

 

[Audioguru]

The fluorescent tube needs a higher voltage to turn on when it is cold. A higher voltage from the ballast needs more turns of wire then the ballast costs more. So cheap ballasts do not light a cold fluorescent tube.

My compact fluorescent bulbs use an electronic ballast and outdoors begin to light very dimmly in winter. They are rated for a certain minimum temperature. They have always lighted even on the coldest nights.

A highway was built in my city with fluorescent tubes for the on and off ramps. They didn't work in winter so they were replaced with a different technology.