flourescent ballast resistance

[stj]

Re: flourescent ballast resistance

that sounds more reasonable for a coil - thats why i started the thread

[eccerr0r]

Re: flourescent ballast resistance

I have an extra magnetic ballast for F15T8 that I swapped out, DCR=26Ω

[CapLeaker]

Re: flourescent ballast resistance



I am sure you know that already. Lol

[stj]

Re: flourescent ballast resistance

it's a philips PL tube,
totally dead - maybe it's a bad lampholder or broken wire.
the problem is it fits into a tight housing - and the light is used in all directions.
so no room to use an electronic ballast and the tube only has 2 exposed pins

i thought about winding led strip onto some copper water pipe to give 360' illumination, but it's a last resort.

[CapLeaker]

Re: flourescent ballast resistance

The one I dealt with had always turn on / flickering problems. The magnetic ballast would be getting so hot, I had to cut a piece of the AC cable off as the insulation would fall off and black stuff would or has ooze(d) out of the ballast. The winding had always continuity... but the resistance was lower than that. It was rare to find an open magnetic ballast, at least for me.

[redwire]

Re: flourescent ballast resistance

That seems reasonable. You can check if there is a ground fault, winding shorted to case.
If the overall startup current is too low I think the starter will just sit there trying to get the filaments to warm up. You can see if they are glowing at the tube end.

I would suspect the tube. Some you can light up on your bench, just power the filaments with a few volts and put at least 30V current-limited end-end on the tube. Newer tubes run out of mercury and go open-circuit (end-end), they need too much high voltage to start and then don't stay ionized (on) and flicker.

[CapLeaker]

Re: flourescent ballast resistance

I just switched out a whole bunch of these old magnetic style ballast lighting system and converted it over to LED. From what I recall, those old ballasts were like drenched in a tar like substance inside making a repair very difficult. If they break, it’s due to shorted winding inside mostly. At least mine where always shorted when I had to deal with it. What is it T8 or even a T12? Got an insulation tester?

[stj]

Re: flourescent ballast resistance

component tester says: 141.6 ohms 3.35 henrys

hmm - doesnt sound like shorted windings.

[stj]

Re: flourescent ballast resistance

no, it uses a glow-starter, just an oldschool 2 wire ballast

[redwire]

Re: flourescent ballast resistance

I would measure its inductance. F14T5 is 14W 0.265A lamp current, need around 900ohms impedance, so 148R from the coil and maybe ~2.5H is needed. Using 240VAC and 40V tube drop for rough math.
Does the ballast have a winding for the filaments, I would check that as well. It might have gone open in the tube. Philips tubes give some tube specs but magnetic ballasts I could not find info on.

[stj]

what should a 13w magnetic ballast look like?
i have a setup playing dead here - ballast is reading 148ohms
that seems high but i have no other ballasts to compare against anymore!