Bench test for "ballasts"?

asop

Is there a way to do this? Ballasts are from F12 flouresent fixtures. Thanks

jimdeere

A Fluke non-contact voltage tester.

booter_one

On the bench, if you know the correct output voltage a DVM, Fluke or similar will let you know the output with no load. If there is an internal short, it may or may not pick it up. A fool proof way is to have it in the fixture with new lamps. If they continue to flicker after warm up, the ballast is most likely internally shorted.

Were the existing lamps dark on the ends? Another very likely area for problems is the wires working their way out of the lamp-holders (tombstones). A good ballast with one of the wires loose will cause problems. On the older t12's they were usually good unless there was a black tar dripping off the ballast. Older ballast have PCB's so handle with care. Hope this helps.[:)]

ChrisInTempe

Here's a couple of do it yourself webpages about it:
http://homeguides.sfgate.com/check-ballast-bad-fluorescent-lighting-39399.html

http://www.doityourself.com/stry/how-to-troubleshoot-electronic-ballasts

Some videos too:
http://tinyurl.com/qgdcm5w

However there's a very practical way too. It is a good idea to have spare tubes anyway. So buy what the fixture takes. If changing them didn't work, then change out the ballast. The worst case is you have spare tubes ready to use when needed.

asop

Thanks guys, very helpful. Tried the changing out the tube approach first, some fixtures worked and others didn't. The ones that didn't I then changed out the ballasts, again, some then worked and sone didn't! Very frustrating as I have MANY fixtures I'm attempting to get in proper working order. This (ballast test) approach will help me hone in on what might be the problem.

ChrisInTempe

Oh so this is an industrial building, business location or something like that? Well if changing ballasts and the lamps doesn't work the lamp fixtures could be corroded, or a switch or breaker someplace.

jimdeere

Careful that the old ballasts (manufactured before mid 70's) may contain PCB.
No danger unless there is a black sticky substance leaking out.
T-12 lamps were supposed to be phased out by now because of the mercury content,
but they are still widely available.

wiz1997

Depending when they were installed some may even have a toggle switch or even an inline fuse holder located on the fixture somewhere.

These became required so that an electrician could disconnect just the one light fixture to replace a ballast, instead of turning the entire circuit off.

Just something to look for.

If lamps have been replaced and the ballast has been replaced than the only thing left to check is the sockets.

The sockets get brittle from the heat and crack.

The spring clips in the sockets will get loose and the wires will back out.

A ballast is very much like a step up transformer, it increases the voltage.

Be careful when checking a ballast the voltage at the sockets or output of the ballast can be in the tens of thousands of volts.

Probably won't kill you, but it will get your attention.

mogley98

I got in a hurray once and replaced a 3 bulb fixture with a 4 bulb ballast and forgot to cap the leads for the 4th bulb. One of the leads brushed my arm and did a little arc welding on my arm but not near as bad as getting hit with higher current.

ChrisInTempe

The output of a ballast is well within the range of being fatal for voltage and current. That doesn't mean it kills you. Killing you requires the current to pass through and disrupt the heart or brain.

If working with the wiring always be sure the breakers and switches are off. Then verify with a voltmeter on the input side of a ballast, or whatever it is you are working on.

No big deal when simply swapping out a lamp, just handle it by the glass.