Fluorescents keep burning out

[Rockyd]

In mechanics shop with a high ceiling, and high ambient temperature, can't keep fluorescents from burning out (8 foot fluorescents). The lights are mounted direct to the sheetrock and need to be as tall as possible for clearance of large trucks. The garage doors are open continuously here so the temperature range is from about 30 on a low in winter, to about 130+ in the summer (110 here in the desert southwest yesterday)

Owner says the ballasts and bulbs have been changed to many times to count. Only easy solution to assist keeping the ballasts cooler would be to mount the fixtures on a 7/8" piece of strut. I don't thing it will matter that much.

Only serious load draw on the system is 3 phase large air compressor that is always seen in the incadescent lights when the compressor kicks on.

The shop has a bolt on 225 A panel ancient Square D panel, and all the gear is tight. The power from the utility is 3 phase Delta, with a wild leg. Various times of the day have turned up various voltage readings. On the wild leg, I've read as high as 215 volts in the evening, and as as low as 207 volts mid-day. The two other legs have read anywhere from 114 to 125 volts.

The owner would be willing to buy new lights if he new they would work. I'm looking for a reasonbly priced fixture, and lamp set up that will work for him in a flourescent fixture style, or recommendations to solve the problem at hand now. Thanks in advance for all recommendations to solutions, or replacements, that will work.

 

[LarryFine]

On the wild leg, I've read as high as 215 volts in the evening, and as as low as 207 volts mid-day. The two other legs have read anywhere from 114 to 125 volts.

Sounds within expectations to me.

The owner would be willing to buy new lights if he new they would work. I'm looking for a reasonbly priced fixture, and lamp set up that will work for him in a flourescent fixture style, or recommendations to solve the problem at hand now.

New T-5 fluorescent fixtures with multi-voltage electronic ballasts.

Also, look into attic-space ventilation to reduce the ceiling temperature from above.

 

[dab]

i wonder if arc welding can be the culprit.

 

[Rockyd]

Thanks Larry,

One of the great things about this forum, is that there's lot's of sharp people stop by, and offer good direction!

I'm doing a little research on T-5's, and looks like a good idea. Place called the Lighting Research Center has pages of research that's proving to be interesting reading on product -

What are good applications for T5 lamps?

T5 lamps differ from T8 and T12 lamps in length and socket size. T5 lamps also require different ballasts than T8 or T12 lamps do. These differences between T5 and T8 lamps make it inappropriate to replace T8 or T12 lamps with T5 lamps. For retrofit applications, the entire luminaire should be replaced with a T5 system. T5 luminaires are usually used in new construction projects. Because T5 lamps have smaller diameters, shorter lengths, and higher luminances than T8 and T12 lamps, they are more suitable for indirect lighting, direct/indirect lighting, direct lighting for high-bay applications, and wall-washing applications.

Fans working in the overhead may save money against the air conditioning bill too.

Dab,

Hadn't thought about arc welding. They don't weld much in their shop, and when they do, it's strictly MIG (probably pretty ugly wave form), however, there are two welding shops next door that are MIG and Stick welding outfits. Share same group of transformers on the pole.

 

[Pierre C Belarge]

What about a different type of lighting, such as an HID type fixture?

 

[robbietan]

do the lights flicker all the time or do they flicker only when they are welding?

having those multi voltage lamp ballasts should protect the fixtures from these 'bad waveforms'

 

[Rockyd]

Pierre C Belarge,


In regard to HID, I'm held hostage indoors to staying close to the ceiling. I've installed a couple of MH yard lights out front for security, and they've done pretty well. Inside, I have large box with roll up doors, and a few mandoors, they fix lots of big cube vans (UPS, FED-EX, Fire vehicles, etc, that crowd the ceiling, so stuck with a fluorescent, of some kind.

robbietan,

Lamps make it about a month before they start with the flicker, and then some seem to almost go full life cycle in the back of the shop (course they are the ones where the work isn't) and where the environment is most consistent. Am planning on talking to owner about considering the T-5's, maybe a couple right inside the doors, where there is worst case scenario for environment consideration to effects on fixture/luminaire, and see if there is vast improvement, to expedite a change to where everyone is happy. to insure stability in the office the have all the computers hooked up through 15 minute (mini)UPS units. I thought it would be pretty pricey, and not best solution to consider for fixxing about 10 to 12 fixtures.

If these T-5's are anywhere what the write up is, be nice to sell satisfaction for all, with some new lights, that actually do what they claim.

 

[jamesguy10]

Just last month, I wired a mechanic shop such as this with 20 foot ceilings. I brought in my electric lift and put up a bunch of t5 fixtures. They run cool, and provide more than enough light. They were mostly 6 lamp fixtures, and a couple 4 lamps. I put them on relays, and controlled those with momentary contact switches. since the lamps have more than one ballast in them, using the relays i was able to switch the ballasts separately to create different levels of light. It worked out really nice, no problems yet.

 

[Mr. Bill]

I think that the T5's are a better solution since you don't want HID's. The T5's like temperatures about 18 degrees F hotter than T12's and T8's. I'm still a little concerned about 130 degrees at the ceiling. Mount the new fixtures on unistrut or something that will provide an air space above the fixtures and try to get an open fixture with vents on the top. The more you can get air to move around the lamps the cooler the they will be. And try to avoid 3, 4, and 6-lamp fixtures since those get hot even in a conditioned space.

If the coldest temp is around 30 degrees you shouldn't have any start up problems. It may take a few minutes for the lamps to get to full light output.

 

[Builder]

Are they wired to the high or wild leg?

 

[Rockyd]

Thanks all for the suggestions! I will have an afternoon beer after work with the owner, and see about getting him to consider a couple of these T5's on junior (7/8") strut. I'm convinced that it is a workable solution, and hope a couple will sell him on the fact too.

Best throw a fan (attic) in there to to save money against the additional run time on the A/C unit time cycle also.