Question about halogen bulbs.

In the past these were always 12V, but now some
of the same physical size are coming out in 240V.

1/ Are the 12V ones being phased out?
2/ Are the 240V ones as good as the 12V ones?

 

Helps to say which country you're in, and I assume you are referring
to G9's versus 12V capsules, or GU10 versus MR16?
In 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.

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.

 

Halogens can be made in any of the standard voltages used for lighting. The
first ones (about 1957) were, I believe, aircraft types; but 120 volt
designs soon followed.

The halogen infrared technology (HIR) looks like the best way to
substantially improve halogen lamp lumens per watt. A lamp being introduced
now, for example, which is called the "2X", draws 50 watts and yet delivers
1600 lumens at 1500 hours rated life which is the rating of the so-called
"standard" 100 watt household bulb that's being phased out. 30
lumens/watt -- quite an improvement for a lamp that's been rated for about
half that for years.

See:
http://www.energystar.gov/ia/partners/downloads/meetings/2011/The 2X Lamp.pdf

Terry McGowan

 

That was one year ago, circulated by some pro-ban lobby group.

Where is the mains voltage product? Will Venturelighting offer more
than vapor?

 

Venture is making 120 volt GLS product now (I have several). I think the
factory is in India. But, I haven't heard about 220-240 volt product.

Terry McGowan

 

They're called "40W G9 240V FR". And they have a
frosty appearance.

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.

I'll use a thermistor to fire them up slowly.

I 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.

I 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.

 

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.

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.

See: http://www.cucumber.demon.co.uk/lights/adapter.jpg
These are designed to position the filaments in the
same (optimal) position as they were with the mains
lamps they replace.

 

I enclose some pictures of the chandelier work in
progress.

1/ The old chandelier stripped down:
http://imageshack.us/photo/my-images/222/imgp3379reduced.jpg/

2/ Threading wires thru intricate brass work. The
application of gentle heat at the point of the
white arrow actually softens the PVC insulation
allowing easier working. With plenty of talc of
course.
http://imageshack.us/photo/my-images/132/imgp3376reduced.jpg/

3/ The capsule and holder arrangement. The 10mm
bayonet-type brass holders are sawn off as shown
to expose more of the capsule. Note how the pins
of the capsule fit into the wire sockets of the
holder so that the screws thereof tighten the
wiring and the capsule pins. The retractile
terminals are left in place and ignored. Pictured
is a 3-lamp bottom section of the chandelier with
the wiring in series.
http://imageshack.us/photo/my-images/836/imgp3438reduced.jpg/

 

You may find that clamping the pins in this way, particularly
with thermal cycling, might cause the capsule to crack after
a while. May also cause deteriorating connection quality,
resulting in local connection heating.

Also, the heat conducted back will overheat regular PVC
and heavily oxidise the copper conductors, generating
increased contact resistance and more heating.
I think you'll need to use some higher temperature cable
(e.g. ptfe insulated) with high temperature bootlace
ferrules to protect the copper at the terminations.

 

Heavens! I'll run a test via a variac and report
back.

 

I inserted 50W capsules and ran them in series
with a variac at full power (36VAC) for 1.5Hr.
http://imageshack.us/photo/my-images/163/imgp3439heattest.jpg/
At the end of this time the brass holders were hot
though they could be held with the moist fingers
without too much discomfort. There was no "heat
small" of hot insulation.

For the end use I'll use about 30W capsules and be
sure I solder the wires that enter the brass
terminals, and be sure the solder runs up under
the insulation for a ways to protect against any
corrosion.

 

Standard PVC used in UK wiring is rated 70C max.
At that temperature, it has a life of around 20 years.
Life drops very drammatically above that (and increases
very drammatically below, to over 1000 years at 20C).
There's also an increased temperature rated PVC,
which allows operation up to 90C. This is what's
typically used as internal connecting wire inside
light fittings. Above 90C, you want a different
insulation material.

Never solder in this way - that guarantees the
connection will fail because the solder will creep
under pressure and the contact pressure will quickly
drop and form a bad connection. You should crimp on
a bootlace ferrule to clamp in terminal (or another
type of crimp connector suitable for the terminal).
Alternatively, use cable with solid core conductor
(rather than stranded).