Flickering Fluorescent light question.

Re: Flickering Fluorescent light question.

Jack Guzman from Maine

usually when I get that it means the bulb is going. Replace it and if that doesn't stop it you need a ballast. I'm no expert.

Re: Flickering Fluorescent light question.

William Duffield

While you are up there, why not just replace the whole fixture with an LED fixture? It will save you time and money in the long run, avoid annoyance right now, and improve visibility in the shop.

because....

Bill Tindall, E.Tn.

...converting to a T8 will cost less, take less time, provide more light and offer more options for color and quality of light.

If Barry's T12 is old it likely has a magnetic ballast. They are inefficient, hum and flicker at 60 Hz. A better option would be to replace the ballast, a 5 min job, with a T8 ballast and lamps. Cut wires to T12 ballast, wire nut on the new ballast, screw it onto the fixture and done.

Re: Flickering Fluorescent light question.

Bill Tindall, E.Tn.

Could be any of the options you listed.

1. swap lamps. Is the current lamp black on the end? The black is tungsten from the filament. If the tungsten has sublimed to the lamp there is less, or none, left for a filament.

2. If a new lamp doesn't fix the problem replace ballast with a T8.

The availability of quality T12 lamps is limited to none. I would have be destitute to continue milking a T12 for its remainder of life.

Re: Flickering Fluorescent light question.

Tom Norton

I bought new LED bulbs from Green Depot. My what a difference! No noise more light.

What I did.....Success.....I hope

Barry Irby

I looked at the bulbs Tom suggested, but we don't have a Green Depot locally, so I checked Home Depot. They had Feit Electric brand 4 ft. T8/T12 17-Watt Cool White Linear LED Light Bulb. I have seen similar bulbs before, but they required electronic ballasts. These bulbs do not. They were $9.92 each. At that price I decided to give them a shot. 1700 Lumens @ 4100 Kelvin.

How's this for an Amazon style review? I just installed them. Just like installing any fluorescent bulb. They are stunningly bright compared to the failing T-12 bulbs that were there. They put the T-8 bulbs in other fixtures to shame. I ran them for a minute or two, turned them off and back on. They came on instantly. 30 seconds, off again and I left to report my success to all of you waiting with baited breath.

If they continue to operate for the promised "up to 50,000 hours" I will be very pleased. Much easier than replacing the ballast or fixture. (I stopped at a local hardware and they wanted $24.59 each. Did not buy them. For that price I would go to new LED shop fixtures.

Really?

Bill Tindall, E.Tn.

"1700 Lumens @ 4100 Kelvin. They are stunningly bright compared to the failing T-12 bulbs that were there. They put the T-8 bulbs in other fixtures to shame."

It is easy to find T12 that provide 3500 lumens and T8's 2800 to 3000. Was this evaluation done with a light meter or by looking at the lamp? If you look at the lamp you are assessing the brightness of the fluorescent covering which is dimly related to the amount of light provided. For example, the lamp of a T8 will always appear brighter than T12 even though the T12 provides more light. Why?

The circumference of the T 12 is pi x 12/4 inch. It is this illuminated area that one looks at when scrutinizing the lamp. T8 circumference is pi x 8/12. If both lamps provided exactly the same lumens on your work bench the T8 lamp surface would appear 12/8 brighter.

Re: Really?

Barry Irby

You are correct. I did not use a light meter. Wish I had one.

As you are well aware, lighting is much more complex that it would appear. Pardon the pun. Many things come into play. Even the orientation of the bulbs. East west vs. north south makes a difference. Dust on the bulbs is important in the shop.

In this case there might be the effect of the reflector. Apparently these "bulbs" have an internal reflector or at least the individual lights are all aimed in the same direction and you can rotate the bulb to aim the light in whatever direction you prefer.

It is obvious to me that these are putting a lot more light on the work surface. Looking at the bulbs was intense, but I also looked at the work surface and I went outdoors to throw the old bulbs away I looked back through the shop windows and it was impressive.

I have replaced about a half a dozen of the old magnetic ballasts with new electronic ones and replaced the old T-12's with T-8's. I am modernizing any way I can.

Re: Really?

A.J. Hamler

Not sure what your shop is like in the winter, but you'll also find that the LEDs are unaffected by the cold, unlike fluorescents.

And whether you can detect it or not visually (some people can't) there is no flickering whatsoever. After a couple hours of fluorescents I used to get headaches and never knew why. That stopped when I switched to LEDs.

Enjoy.

What's missing is hard data

Bill Tindall, E.Tn.

"I went outdoors to throw the old bulbs away I looked back through the shop windows and it was impressive. " This observation is reliable. But any change from ancient T12 magnetic would be a vast improvement, T8 or LED. Magnetic ballasts are inefficient, they hum and flicker at 60 Hz. If the object is the most light per fixture, consider T5HO at 5000 lumens per lamp, 20,000 per 4 lamp fixture.

Yes, LED lamp has an internal reflector. T8 fixture has an external reflector. It could be an equivalent result at the bench. It certainly is not a case of reflector vs no reflection.

What is missing is light meter data at the bench, or what ever is being lighted. I have the means of measuring illumination. I'll see if I can find some place to do a comparison- T8vsLED replacement, illuminating a bench.

Flicker and temperature

Bill Tindall, E.Tn.

It would not matter what you replaced your ancient T12 magnetic technology with you would have seen the same improvement. T12 magnetic ballasts flicker at 60Hz.

I suffered the same problem as you. Some do and some don't. It was solved 20 years ago by my brother-in-law the lighting engineer. He explained the situation and directed me to electronic ballasts that don't hum or flicker. Magnetic ballasts have not been available to buy for at least 2 decades, so anything modern will solve the hum and flicker problem.

A cold shop could be a reason to use LED lighting. It gets brighter as the lamp gets colder. Fluorescents can have limitations in cold environments.

Thanks for the review!

Tony - Memphis

My shop started life with 8 4' T12 dual bulb fixtures. That was heaven compared to my old "1/2 the garage" shop! In the past couple of years, I replaced the ballasts and went to the T8's . That was a noticeable improvement and the newer ballasts seemed quieter and quicker to light up (no biggie, but an observation). I've added some task lighting that is LED bulbs and I have ben real happy with that. There is some mathematical relationship where amount of light required is a function of age! Gotta be. My wife is an artist and I replaced the old tubes in her studio with those fancy Hypherion or whatever that have a high CRI, etc. Wow! She loves them. More and better light. Anyway, nice to know there is something available local now. I'll have to take a look at our HD. I'll probbaly wait until the current bulbs start to dim to invest in new ones. I just spent all that money on ballasts and bulbs a couple of years ago. Funny, in the last 20 years in this shop - I've added lots of light and lots of reading glasses! Neither was required when I started! Enjoy your new lights!

Oh, there are numerous freebie apps for measuring light. Have no idea how accurate, but they seem to work and could at least give relative numbers. I don't care about measurements - proof is in the effect - if it looks better, it IS better. And yes, I play an engineer by day (mechanical).

measurement

Bill Tindall, E.Tn.

Back in the day cameras had light meters. These could be used to measure light intensity. Absent a light meter a camera that provides numerical lens settings can be used for comparison. A large lighting store might provide a loner meter.

Persons visiting my shop usually comment on the lighting. I must be doing something right, or at least my brother-in-law who advised me.

Subjective measurements are easy to misinterpret. Hard to hold all the variables the same for comparison. Best to arrange lights to get sufficient foot candles on the task. For detailed work 200 foot candles is required, more so for senior woodowrkers. Outside shade is 500, by comparison, which is why windows in a shop are so helpful. Background light about 20 foot candles. I can say from attacking this problem that getting 200 foot candles at the bench is not trivial without task lighting.

I have not experimented with LED task lighting but I suspect it would now be preferred over halogen lights. A huge advantage is the convenience of battery power source.

aside.....

Barry Irby

My friend whom I attend freight auctions with bought a pallet of LED strip lights. They are 20' rolls and sell at Home Depot for close to $40. They do not have the transformer/dimmer, and they run on 12 volts. Tey are sticky back like under the cabinet lights. I saw a demo of running the under the house on the DP and Bandsaw. Anyone interested, he is selling them cheap, less than $10 with shipping included. Could be fun to play with. Completely unscientific, but they are Bright!. And Dimmable. Ask and I can get more details.

Bill is correct about my poor observation. At an emotional level the new tubes were hugely better and brighter and while I am sure both of those are true, I can't produce any measurements to prove them. OTOH, for $20 and a minute to install them, I am very pleased. I will have to wait to see if they and the ballast hold up.

I had an excellent use for the 60 cycle flicker of the old fluorescents. My Performax has a 3600 RPM motor and one of those "interlocking finger" couplers from the motor shaft to the drum shaft. One set of fingers is black and the others are white. When the unit was running freely, the coupler would strobe and appear to be standing still. If the sander loaded down it would appear to rotate slowly. I could fiddle with the depth of cut and feed rate to keep the drum speed constant. (Did I mention I get bored sanding?)

light meter

John K Jordan

>>>You are correct. I did not use a light meter. Wish I had one

A light meter is useful and not expensive.

I use this one:

https://www.amazon.com/gp/product/B0075ZS8VQ

While you are messing with the bulbs and fixtures how about just cleaning the contacts and coating with dielectric silicone grease to eliminate one possible problem.

Or just replace the ancient bulbs and fixtures with T5 fluorescents. You might need to wear sun glasses then.

JKJ

T5's

Bill Tindall, E.Tn.

"Or just replace the ancient bulbs and fixtures with T5 fluorescents. You might need to wear sun glasses then." Could not agree more. They are to way to get most light per fixture or sqft, if these metrics are important. My ceiling was literally covered with T8 fixtures to get 200 ft candles on bench. They are all gone to be replaced by 2-T5HO fixtures.

I find it curious that people that have lived with mag ballast T12 for decades overlooked the successive availability of electronic ballast, T8, then T5. What about LED technology motivated a modernizing that these other advancements didn't?

Re: because....

William Duffield

In cases like my shop, I can't imagine how replacing the ballast and tombstones could cost less than just replacing the whole fixture. I've done it both ways, and also used a couple other strategies. Nothing could be easier than unplugging the old fixture, unhooking it from the hanging hardware, opening the box containing the new fixture, hooking it to the existing hangers and plugging it in. You don't even need to turn off the power to do the conversion, and immediately start saving money on your electric bill, get better visibility, and drastically reduce future maintenance effort. Your method, in addition to the wiring modifications, starts with finding the right ballast, and in the end you just replace T12 problems with marginally improved T8 problems. Also, Barry's problem is much more likely to be a failing bulb than a failing ballast; most of the magnetic ballasts failed the smoke test years ago, and the chances are very good that he already has a transistorized ballast.

Re: Really?

stuart johnson

They are also very tough. I was doing some painting with all the light fixtures removed so I plugged in a two bulb led fixture from the shop. I was laying on the working great until I stepped on it. There was a crunch, tinkle and then no light. I broke one bulb and knocked the tombstone out of whack. Glass (plastic) poured out but the internal light strip was okay. I fixed the tombstone and plugged both the good and bulb in. Both worked fine but the broken one is flimsy.

Re: T5's

John K Jordan

>>>I find it curious that people that have lived with mag ballast T12 for decades overlooked the successive availability of electronic ballast, T8, then T5.

I put nine T5 fixtures in my shop in six "zones", 36 bulbs advertised at 4000 lumens each, electronic ballasts. Bright. Wiring for different zones lets me leave off those lights on the other end of the shop. (I have a string of low wattage ceiling lights through the rooms in the shop, bright enough to walk and fetch tools without turning on the bright lights.)

One huge advantage to the electronic ballasts is the 4-bulb fixtures come with the capability of controlling half of the bulbs independently. I've wired most of them this way: a main switch turns on the power to the fixture and a secondary switch, which I mount high on the wall, enables half of the bulbs.

I leave the secondary switches off almost all of the time so when I turn on the lights just two bulbs in each fixture light, but when I want more light in the fixtures, for example near the table saw, I can flip the secondary switch on for just those fixtures. This cuts the power usage way down but the extra light is on tap when I want it. The older the eyes get, the more light they need.

JKJ

A few misconceptions in your reply

Bill Tindall, E.Tn.

You seem to be making changing a ballast as hard as you can imagine, not as easy as it is.

"I've done it both ways"....then you should have observed that the tombstones for T8 and T12 are equivalent. No need to replace.

" Nothing could be easier than unplugging the old fixture" ....unless fixtures are wired into the shop wiring and not plugged in.

"immediately start saving money on your electric bill"....what is your yearly saving?

"get better visibility" data to support this statement? certainly not supported by the lumen output nor CRI on the lamp boxes.

"and drastically reduce future maintenance effort." If the LED lasts as long as advertised I agree with this point. Zero maintenance vs changing a lamp every 10 years is an infinite, if not drastic, difference. That said I have high quality SPX GE lamps in the living room that are 20+ years old.

"in addition to the wiring modifications".... there is no modification, snip, snip, snip and 3 grey wire nuts. Done

"starts with finding the right ballast"..... agree, if reading comprehension is a problem this task could be difficult.

"and in the end you just replace T12 problems with marginally improved T8 problems"....a T12 mag ballast is replaced with one that is more efficient, doesn't flicker or hum. If the improvement was trivial as you propose why do you think that knowledgeable people switched 2 decades ago to T8? Or that my brother-in-law, the lighting engineer for GE, recommended it to me?

I am not against LED lighting. I do think that lighting decisions should be informed by reliable data.

BTW Barry had mag ballasts and I have never had one melt, though I know they can. But that is not how they normally die.

Re: A few misconceptions in your reply

Walt

The only light meters I have are in my eye sockets but 4000K LED tubes suit me. I just removed the ballasts from existing fixtures and installed hot-one-end LED tubes. For me No ballast > electronic ballast > magnet ballast. Different strokes for different folks I guess. Our fluorescent tubes didn't seem to live very long, that could have been poor quality or frequent power cycling. I've heard/read that fluorescent tubes don't like frequent on/off cyles, LEDs don't care.