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Author Topic: halogen lamps  (Read 11572 times)

Offline debook

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halogen lamps
« on: June 20, 2004, 06:58:00 pm »
Over the last few years most of the cheap 12v halogen lighting has been replaced in shops with 240v versions. OK, they are cheaper to buy as there is no transformer, but the running cost is presumably higher? 240v lamps have a very short life compared to the 12v ones and also push out a lot more heat.

Can anyone clarify this for me?
« Last Edit: November 14, 2004, 01:16:19 am by tim »
Frank Andrews

Offline Mónico González

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halogen lamps
« Reply #1 on: June 21, 2004, 11:22:00 am »
Hi debook,
presumably this could be to avoid the costs of step-down transformer, to simplify the wiring, to allow the use of dimmers which cannot be used to drive reactive loads, and at last, to eliminate the possibility of generating audible 50 Hz "buzz" coming from xformers at indoor fixtures.
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Offline James

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halogen lamps
« Reply #2 on: July 25, 2004, 07:02:00 pm »
Hi Frank,

The 240V MR16 versions put roughly half as much light in the centre of the beam as the 12V alternatives, so they are considerably less efficient.  However lifetime is still 2500 hours.  The main problem is the big filament which leads to imprecise beam control and low colour temperature.

In fact, the 12V market is one which has almost completely now been taken by cheap Chinese sources.  Thus a 50W lamp which used to deliver 900 lumens and last 5000 hours, now typically delivers 700 lumens and lasts 1000 hours.  But the price is halved and that seems to be all the customers care about today.

240V version are still mainly produced by the Western manufacturers so the quality isn't actually all that much worse than the common Chinese 12V alternatives in reality.  But give it another year and I expect all European production of 230V halogen reflector lamps will cease.  Customers have no real interest in lamp quality today and within another year or two the Chinese are expected to completely take this market also.

James

Offline debook

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halogen lamps
« Reply #3 on: August 23, 2004, 10:39:00 am »
Thanks for the replies, for the most part my 230v ones are lasting a lot less than 2,500 hours. Whereas some of my 12v in daily use are well over 5,000 hours by now.

I suspect the cost issue has more to do with the stores, as everything gets cheaper the efficiency is falling all around - not just lighting! Where do you ever see quality claims on light bulb packaging - sine the 1950's at least?

------------------
Frank Andrews