I light my apartment with two halogen lamps similar to these I changed the bulb in one about six months ago, and since then it’s had a tendency to spontaneously shut off after being on for a while. After several minutes it’ll turn back on.
At first I thought it was because of a new bulb, but that was this summer. It’s rather irritating. Is this some kind of failsafe that shuts it off when it gets too hot?
It does sound like some kind of thermal shutoff protection. Check the bulb socket for a rating label indicating the maximum wattage bulb that should be used. Then make sure the new bulb does not exceed this value. If this is not the problem, make sure the fixture is clean inside. Perhaps dust or dirt buildup is keeping the heat from dissipating properly. Use a can of aerosol duster to blow it out thoroughly. If it’s not that, then it’s very possible, even likely, that the unit is simply failing and needs to be replaced. Just in case, though, it might be worth trying a bulb that’s much lower in wattage than the maximum. If the thermal cutoff circuitry, assuming it exists, is iffy then running it low might keep the problem from reocurring.
What Q.E.D. said. It certainly sounds like a thermal overload of some sort is the culprit. You may be having a problem with the transformer in the lamp. I googled a bit and couldn’t find any specifics on the circuitry in a standard torchiere lamp, but I did find a lot concerning the fire hazards, recommended lamp wattages, and general energy inefficiency of these lamps. This site was very informative as was this one. Not that I am offering any judgement on the lamps, these were the first sites Google turned up that were factual rather than retail in nature.
A lower wattage bulb will let you operate on high with less power consumption, so may alleviate the problem. To test this before purchasing a new bulb, run your lamp on the low setting and see if it trips off. If it doesn’t, then a lower wattage bulb should work for you. If it does trip off, then likely a new lamp is in your future.
True enough, but I don’t think that’s the problem here. Touching the quartz bulbs leaves oils on them which causes hot spots. The upshot of this at high wattages is the often rather spectacular failure of the bulb when the quartz envelope explodes. You haven’t lived until you’ve been under a TV studio fill lamp when the bulb blows up like that. Good times.
I have one like that. It had a cage on the top and a sensor. It turned off by itself repeatedly, making me very angry.
My solution was to remove the cage and bend the sensor back, forcibly [see “note” below]. It seems to work fine now. It turned off once a year ago after a wasp flew into it, but otherwise, it’s in good order.
*BIG NOTE: Removing the cage and modifying the sensor is technically a fire hazard, so proceed at your own risk.