Many new electronic ballasts now have end of life detection for the bulb and for the ballast.
As bulbs reach the end of their life more current is required to light the bulb. This generates more and more heat at the electrodes and can eventually crack the glass. (you've probably seen this in high output bulbs in old freezers with magnetic ballasts). The higher intensity of the bulb (HO or t5) the greater the possibility of a catastrophic failure.
Electronic ballasts will shut down when they detect the bulb is reaching the end of its life. when the EOL circuit activates you will get intermittent operation and the bulb will go from working fine to not working and back again.
Always try a new bulb first. If that doesn't work check that the connections are good and if they look fine replace the ballast.
Electronic ballasts have a lot of capacitors inside and when these capacitors fail you get intermittent starting or no starting. Just like a compressor
I'd love to hear the recommended method of testing a ballast with a meter?
My brother is a master electrician and tells me that there really is no way to test ballasts with a meter. Method of craig1 is about the only option. Replace bulbs, check wiring, replace ballast. It amazing how quick some of these ballast go bad. Check on warranties, never had paperwork for any, they just give me new ones.
If the ballast is getting power and is not warm, change it. End of story. Makes it real easy when multiple ballasts are lined up next to each other. Also, if a bulb is not obviously black you can ohm out each end and look for 3-4 ohms. Both ends of a bulb need to measure good for proper operation. These are my two most used no-nonsense test methods.
I used to do a lot of fluorescent repairs in C-Stores and small markets. I tried getting the scoop on how to troubleshoot them and how the dang things worked from a half dozen good electricians, electrical supply types and even a lighting engineer. Nobody had any more knowledge than I did...which wasn't much.
It always boiled down to replacing the bulb(s) > ballast > sockets, in that order. In the last 20 years I can only recall one issue beyond that, involving the wiring.
In the past 5 years or so most of my customers have opted to for a handyman, try to do it themselves or expect me to do it as a favor with the parts they bought at HD. :censored:
Noticeably, their stores are much darker than they used to be. ;)
FWIW I'll be getting a 1000V meter since most I see run over 600V
Originally Posted by jpsmith1cm
Do you know what V your trouble ballast is supposed to put out?
Most instant start ballasts are 550-600V on ignition for the arc, end of lamp to other end. This is for normal lamps, though, HO and VHO might be different, and I can't recall what program or rapid start are.
check the bulb against the ballast make sure they are compatible. with electronic ballast make sure you have good connections. They don't like lose connections. Make sure your are following the wiring diagram for the set up you want. have a few bulbs and ballast with you sometimes they are bad out of the box. check to make sure the voltage is correct 120 or 277 whatever, I have been changing out T12 to T8's for a few weeks now and some fixtures are just a pain in the :censored: and it comes down to a loose or bad connections. That's all there is. no mystery.
First of all,it's rather hard to retrofit T8's to T5's as the bulbs are different lengths and the lampholders are different. If one the the bulbs was lit before you messed with the wiring, it was probably a wiring problem as the new electronic ballasts can work with one bulb installed. Another good practice is to always install a ballast disconnect in the fixture if you're working on it. The new code calls for it and it helps so you don't have to shut off all the fixtures to service one. I've never had much problem with bulb holders on the newer T8 and T5 fixtures. Of course, the latest and the greatest for cooler/freezer lighting is LED's! There is a huge difference in ballast quality. A name brand (like Advance, Sylvania etc.) will hold up a lot better than some of the cheap ones being installed in the lower quality fixtures.
When the electrodes are all worn out and discharge takes place form the support, they can get cherry hot and crack the glass. T5 lamps are thinner, so the cathodes are in a closer proximity to the wall and more susceptible to damage.
To prevent this, most T5 ballasts have end of life protection.
As for problems in lamp holder, arcing is a problem in refrigerated cases where corrosion in the lamp holder from condensation can cause arcing. For such applications, UL CC rated ballasts are recommended. CC rated ballasts have an arc reduction circuitry.
I have come across some ballasts in Hussmann cases that utilize the anti arc technology. (type CC). If an arc occurs anywhere including sockets the ballast will shut down that bulb or the ballast. Ive seen this with cases with shelf lighting where the bulbs are subject to being hit by customers and product Sometimes it is as simple as reseating the bulbs and cycling the power to the ballast. Worth looking into..
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No need for fancy equipment to test flourescent lights/ballasts. You like to get too advanced on troubleshooting stuff :P. I understand getting all advanced on troubleshooting HVAC and Refer systems but damn JP it's just a simple fixture... LOL
Replace the bulbs, and if that doesn't solve the problem, then it's obviously a ballast issue. :) Now if you are talking about older fixtures you will also have starters involved. In that case I just retrofit the fixture with a newer ballast and do away with the external starter. Also, you can typically tell if the bulbs are bad or going bad by looking at the ends of them, if they are translucent grey or black then the bulb should be replaced.
You can typically test a ballast by using ohms and continuity tests via your meter.
If you really are interested in testing ballasts with a meter then get a Fluke Insulation Tester Meter.