DIYbanter - View Single Post

In article .com,
writes:
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!

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.

--
Andrew Gabriel