Post by Peter JasonOn Mon, 15 Oct 2012 13:54:18 +0000 (UTC),
Post by Andrew GabrielPost by Peter JasonIn the past these were always 12V, but now some
of the same physical size are coming out in 240V.
Helps to say which country you're in, and I assume you are referring
to G9's versus 12V capsules, or GU10 versus MR16?
They're called "40W G9 240V FR". And they have a
frosty appearance.
Post by Andrew GabrielIn the UK, 240V halogens have been around for many years, in similar
(but not identical) format to 12V types. They have different bases,
so they aren't interchangable.
Post by Peter Jason1/ Are the 12V ones being phased out?
No.
Post by Peter Jason2/ Are the 240V ones as good as the 12V ones?
Nowhere near, at least not for anything rated 100W or less, where
12V is more efficient (much more efficient in most cases, even
allowing for losses in transformers).
Also, 12V have smaller filaments, which means that any optics
(lenses, reflectors) can more accurately control where the light
goes.
That's a relief. I am halfway through rewiring
an Empire chandelier of 20 lamps.
I am rewiring it in series for 240V and I want to
use 20 x 12V 40watt halogens.
That will be extremely bright.
I replaced 60W 240V candle lamps with 35W 12V in a central
room pendant, and the light output is very noticably brighter,
probably double, but unfortunatelty I didn't measure before.
I still run them in parallel at 12V, although I have rewired
to cope with higher current draw (and high frequency operation
from electronic transformer which requires much thicker/stranded
wire due to skin effect).
You should probably be looking at using 10W, or 20W max.
Post by Peter JasonI'll use a thermistor to fire them up slowly.
I'm not sure what additional failure modes you introduce
by having the potential for 240V across a failing 12V
capsule lamp, but I would not rule out the possibility
of a low pressure capsule exploding at switch-on.
Thermistor will help here though. Finding the dead
capsule will be painful. See Big Clive's chandelier
http://www.bigclive.com/halogen.htm
for an idea using parallel neon indicator lamps.
Lamp bases for 12V capsule lamps are not necessarily
designed to be safe when operating at 240V WRT ground.
Post by Peter JasonI have adapted the small bayonet holders to accept
the pins of a 12V halogen, and I saw off the
bayonet part that holds the old incandescents so
as to better expose the halogen filament.
See:
Loading Image...These are designed to position the filaments in the
same (optimal) position as they were with the mains
lamps they replace.
Post by Peter JasonI use a conductor of 1sqmm copper - much thicker
than the olf 240V parallel wiring - and getting it
all stuffed into the nooks is most difficult.
--
Andrew Gabriel
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