What are the odds?

[Rod in Forfar]

My son located a large pile of used, good quality fluorescent lights taken from a drugstore undergoing renovations. Desiring an ample supply of lighting for his new garage, he bought the contents of the large pallet, estimated at between forty and fifty eight-foot lights, each with four thin, energy efficient bulbs.

To our astonishment the poor Tacoma could barely carry the load. The reflectors stacked together densely and Charlie and I discovered we could lift only small piles of them. And there were a lot. Similarly, there were a great many bulbs to load onto the top of the pile in my sagging pickup. Everything rode well on the road home after the vendor added air to my tires, though.

In anticipation of the weekend rush I picked a few lights out of the back of the truck, cleaned and assembled them. The first two lit up like champions. Out of the first bundle of bulbs I had two rejects: one was burned, I guess (no way to tell), and one had a prong bent at one end, so I disposed of it.

Bet and I hung the two completed prototypes from the ceiling of my new workshop, as an experiment. Yeah, right. I like the even light.

Flushed with success, I assembled another for Charlie to put up in his garage. All went well until I added power. Nothing. Now what?

I dutifully took the thing apart and checked each connection. No dice. Ballast? I pulled one out of a junked light from the pile and spent twenty minutes wiring it in. Still nothing.

Time for the burnt fingers method. In I went with the multi-meter with the current on. Power to one end was fine. Voltage was a little variable at the other end. Re-jigged things until the flow was steady. Still no lights.

What does a ballast do, anyway? On my way to the house to ask Google, I thought, 展hat are the odds of having two bad ballasts from a collection of working lights? About four times the odds of having four bad bulbs from a similar collection. Come on, now. Four bad bulbs in a row? No way.

I pulled an unwashed bulb from the centre of a bundle and put it in. It lit up. Three more, same story.

Do you apologize to a ballast you have wronged?

So what are the odds of hitting four bad bulbs in a row out of 160 which were working when they took them apart?

Could their failure have anything to do with my amusing discovery that they make a high- pitched hamonic sound when polished with a wet towel? It didn't hurt the others, though.

 

[Opti-Mist]

I can't add any other intelligence to your thread, but I can tell you that I would not have heard the high pitched sound so it would not have entered into my problem solving. I'd still be trying to find something else. As for the odds, any time "rough" handling is involved I'd say the odds are good in finding a few in a row.

 

[vwnotrunning]

I have learned when going through a pile of treasure like this to get one lamp working and utilize it to test other bulbs to ensure you have a group of working bulbs. Then set up fixtures to test utilizing the know good bulbs. Do not hang the fixtures until you have verified the ballast is working. Even then a bad / loose socket will make inconsistent results.

 

[CharlieS]

Actually its quite possible you had two bad lamps out of four. Generally speaking with flourescent lights, if one lamp goes bad, many times neither lamp will light up. There are some exceptions to this, though it's pretty common.
A ballast that hum's or buzzes is usually an indicator of impending ballast failure, (as is a leaking ballast) though there's no telling how long it will be til that failure occurs.
A ballast is nothing more than a transformer that pumps up the voltage to a level that will excite the gas in a flourescent tube. As such they are subject to eventual failure as of course are tubes.
Add to that, you have no idea how many of the fixtures or lamps were not working, or how everything was handled during demolition so rough handling may take its toll on already well used components.
So yes its quite possible you encountered multiple ballasts or lamps that were not in a funtional state.

A couple of side notes, sometimes you can tighten the nuts on the studs that mount the ballasts in the fixture and eliminate the buzz, which is nothing more than harmonics between a slightly loose ballast mount and the frequency the ballast operates at.
Also when you relamp with new lamps, always change the lamps in pairs. Adding one new lamp with an old one will shorten the life of the new lamp. Sort the working used lamps from the dead ones and pair the used ones up together.

 

[davedj1]

did you check the voltage the lights require? Some of the newer flouresent lights automaticaly set the ballast to the voltage the first time they are powered up and can not go back. Maybe they were running at 480? quite common in commercial applications.
good luck.

 

[Iplayfarmer]

...Do you apologize to a ballast you have wronged?

:laughing:

That's a good question. I suppose if the only language broken tractors understand is swear words then other inanimate object may have preferences, too.

 

[George2615]

did you check the voltage the lights require? Some of the newer flouresent lights automaticaly set the ballast to the voltage the first time they are powered up and can not go back. Maybe they were running at 480? quite common in commercial applications.
good luck.

I agree to take the covers off and read the ballast require voltage. Many businesses use higher voltage for lighting. All my ballasts at my place of work run on 277V and won't work on 110V. If the ballasts are the higher voltage type you can replace the ballasts with universal electronic ballasts that work on 110V-277V input. I did 1/2 of my garage with new 4' T8 fixtures that use electronic ballasts. At work when an older T12 (large diameter tube) fixture stops working I replace the ballast with new electronic ballasts and T8 tubes. They draw 1/3 less amps. Also if you buy ballasts check to see that they are compatible with your tubes T8 or T12. The tube you have should have the size on it.

If yours are lighting by changing tubes they may be 110V. Since the store was remodeling they may have had a lot of lights that weren't working.

 

[jonyyuma]

Okay, the lamps have a tiny coil on the end, that heat up the tube. It coil can be broken, especially when the lamp has been burned. read your ballast voltage, they come in all types.Set up one fixture that is known good. process all your lamps thru it, handle them very carefully afterwards. bad lamps contain mercury, it is againest the law to bury them, or burn in fire.Ballast can fail at anytime, so test them on the ground too, before hanging...preventing unnecessary heartburn..