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Question about halogen bulbs.

Discussion in 'Lighting' started by Peter Jason, Oct 13, 2012.

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  1. Peter Jason

    Peter Jason Guest

    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?
  2. 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
  3. Tomsic

    Tomsic Guest

    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: 2X Lamp.pdf

    Terry McGowan
  4. Sepp Ruf

    Sepp Ruf Guest

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

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

    Tomsic Guest

    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
  6. Peter Jason

    Peter Jason Guest

    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.
  7. 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
    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.
    These are designed to position the filaments in the
    same (optimal) position as they were with the mains
    lamps they replace.
  8. Peter Jason

    Peter Jason Guest

    I enclose some pictures of the chandelier work in

    1/ The old chandelier stripped down:

    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

    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.
  9. 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.
  10. Peter Jason

    Peter Jason Guest

    Heavens! I'll run a test via a variac and report
  11. Peter Jason

    Peter Jason Guest

    I inserted 50W capsules and ran them in series
    with a variac at full power (36VAC) for 1.5Hr.
    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
  12. 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).
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