florescent light fitting query??

[tel1e]

Hi all, Just wondering if t is possible to add a starter to a florescent fitting that hasn't got one? I ask as I have 2 five foot fittings that work perfectly well with normal tubes in them...however when one of the tubes gave up the ghost I replaced it with one of those skinny low energy tubes...you know the ones that start off dull but then get brighter!....Now I find that when switched on the fitting with the new tube in doesn't light up...the tube just just glows at either end & makes no attempt to light up no matter how long it is left...however if you flick the switch on & off a couple of times the tube lights up & works fine.

I'm assuming that the fittings that I have haven't got the "ummf" to stat one of these new type tubes so I wondered if it was possible to add a starter to the fitting to help it out....I ask as the other fittings that I have all have starters & they seem to handle the new type tubes with no problem! I have some old fitting lying around that I could take the starters from to try this out but would it work & where in the circuit should I add the starter if at all!

Hope you all understand this as I have tried my best to explain!

Regards, Tel.

[Andrew Gabriel]

It sounds like your old fittings have old rapid start or quickstart control gear -- presumably they didn't flash when starting, but came on slowly over a couple of seconds? Rapid start and quickstart control gear does have problems starting T8 (1" diameter) tubes if it was designed for T12 (1.5" diameter) tubes. The T8 tubes require a higher striking voltage.

In theory you could remove the quickstart transformer and convert it to switch-start using a starter, but in practice the quickstart transformer and the ballast are usually all epoxyed together in a single case which makes this impossible.

Before giving up on it, you might check the fitting is properly earthed -- earthed metalwork near the tube helps with starting, but I think it most likely still isn't going to have enough voltage to reliably strike the arc in a T8 tube. For retrofitting, T8's are only suitable to retrofit into switch start control gear circuits, so you will need to buy a 5' 65/80W T12 tube for your rapid start or quickstart control gear.

[BigWallop]

If you remove the cover of the fitting, then you might find that it has starters inside. Many now hide them away because of decorative, non-obtrusive edges kinds of things, but they still have starters. If the fitting has electronic start, then you can really install another starting lamp in these, so you're stuck with having to change the tube back to the old style, or change the fitting for one with starters.

This sounds like a wrong starter for the size (wattage) of tube problem.

[bigcat]

No.

I suppose if one wanted to get wacky, a piezo igniter could be tried, discharging to the outside of the tube, add a foil electrode. Could be a bit too dangerous though.

NT

[tel1e]

Thank you all for the quick answers & advice.

The fittings definitely have no starters so they must be the ones described by Andrew with the rapid start or quick start control gear. The light does come on with hardly any flickering. I've checked & the fittings have a good earth connection so it's down to the T8 tubes needing a higher striking voltage.

I'll just replace the tubes with T12's & be happy at that.

Thanks for the help.

Regards, Tel.

[Christian McArdle]

Don't bother. Fluorescent fittings cost pennies. Just put a new one up that does have the right starter.

Christian.