About a year ago now, I moved into a new home. In the kitchen there are seven low-voltage halogen bulbs all switched from the same light switch.
Over the last year I have found that bulbs in certain positions need to be replaced fairly regularly - every two to three months. Others however, I have never had to replace.
There is no obvious difference between the locations and I have always used replacement bulbs from reputable sources.
However, on investigating, I found that there are two transformers powering these bulbs. And, you’ve guessed it, the short-life bulbs are powered by one transformer and the long-life bulbs by the other.
I would really like all my bulbs to have a long life, they are expensive and a pain to replace.
Too high a voltage will shorten life, but the bulbs would also be noticeably brighter…And halogen bulbs are MUCH less sensitive to this than regular tungstan bulbs. Dust, cooking grease, fingerprints on the quartz evelopes will acclerate failure.
Are there more bulbs on the transformer with the long life? (or is it smaller, with same number of bulbs?) If a second transformer was added because the first was maxed out, then the heavilly loaded transformer could be current limiting during the cold-filiment inrush time. This would in effect “soft start” those bulbs, and ease the thermal shock when they were turned on.
The two transformers and all the wiring are identical so I am pretty sure that they were both there from the begining.
There is no obvious difference in brightness.
All the bulbs are in a nice neat row above the worktop on the opposite side of the kitchen from the oven and grill. There is a combination oven on the worktop under the bulbs - its right in the middle.
One transformer supplies three bulbs and the other four. However, one bulb has been left blown for some months now, so each transformer is supplying three bulbs.
The bulbs are MR16 12V 20W. All the replacement bulbs have made by General Electric and are supposed to last 2000 hours.
As far as I can tell, all the failures must have occured when the lights were turned on or off. I never noticed a bulb fail, or even misbehave, during use.