5 Feb
2015
5 Feb
'15
3:29 p.m.
On 02/05/2015 02:03 PM, Tothwolf wrote:
I recently converted all of my overhead T12 to T8 (in
my case, new
sockets and wiring along with new ballasts, since the fixtures were made
~1964 and the original wiring was in very bad condition) but what I
worry about is the long term reliability of the electronic ballasts
(basically switch mode power supplies), in particular, the small
electrolytics they use. I don't expect they will last nearly as long as
the original magnetic ballasts did (although at least they don't have
the large PCB [polychlorinated biphenyl] containing oil filled
capacitors the pre-1979 ballasts I removed did).
Well, I first converted all of mine to T8 using surplus GE industrial
ballasts from the 90s. So far, so good--no failures in over a decade..
A peek inside shows them to be pretty well constructed. On the other
hand, I picked up a lot of "SASI" brand ones about 5 years later and
they've pretty much all failed. The most common cause seems to be the
failure of an 0.5 ohm 5W power resistor, which I assume is used for
current-sensing.
I will give the T8 lamps this--they use less power and last longer than
the T12s. About the only reason that I've had to change them is when
the light output has fallen off noticeably. But then, you'd replace an
LED fixture for the same reason--assuming that it lasted that long.
It seems that in this case, you get what you pay for.
--Chuck