On 23/07/2011 21:57, adastra wrote:
> We have built up this device using a standard ballast (ICN-2P-32N) and tw=
o
> 36" F30T8CW tubes.  We turn it on and off simply by controlling the 120 V=
AC
> input to the ballast with a relay.  It seemed to work fine, but the lamp
> life has proven to be extremely short, i.e. the tubes blackened on the en=
ds
> and failed after only a few days of use.

The "cathode" coils are "stripping"

Use a bi-pin at each end tube.

Use a small transformer x2  to keep the "heater coils" warm. Use regular=20
"choke" ballast. I don't know what voltage is required, it's only a few=20
volts.

Tube will turn on instantly. Don't use Electronic ballast or choke=20
ballast "starter" tube

The BBC used to use these so lights in continuity studios etc would come=20
on instantly. They of course also had the transformers and ballast=20
chokes in the corridor to avoid noise, but that's nothing to do with=20
your issue.
--=20
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