Halogen Bulbs Blowing

[MikeU]

In one of our downstairs rooms we have a light fitting which takes 4 40w halogen capsules. These don't seem to last long! Last week, two went together. I replaced them with Crompton THG940F's. Now two have gone again at the same time, including one of the new ones. Altogether I must have changed 7 bulbs in 6 months and, at £6 a pop, I'm getting poorer at an alarming rate.

Apart from throwing away the whole fitting, is there anything I should be checking? I did notice a slight flicker about 3 or 4 seconds after I turned on the light before the bulbs expired.

 

[delmel]

I guess you have the in the little circular surface / flush cupboard fittings. The answer is they do blow regular especially when left on for lenghty periods. Heat is the big enemy, however £6. each is harsh. Where u getting them from. Where u located I will help u get better deal.

 

[MikeU]

Actually, no. It's a centre ceiling fitting with 4 angled "spotlights" each with its own bulb and glass shade.

I got the bulbs in my local hardware shop ( I was in a hurry!). I'm located near Woking in Surrey.

I find it odd that twice now, I've had two bulbs go together. I've read the other topics regarding blowing bulbs and wonder if I have a switch problem or whether the contact the bulbs make with the holders is less than perfect (they are capless, after all).

 

[felix]

Are these mains bulbs or low voltage? I've come across the two (or more) together puzzle before on low voltage halogen bulbs and it goes like this:

1) The bulbs are on a good old fashioned transformer with coils on an iron core.

2) The bulb which is going to blow draws a huge current while its filament vapourizes then nothing.

3) The transformer has leakage inductance which doesn't like having a huge current vanish in a split millisecond. Result - it forces that current through another bulb and blows that one as well.

To find out why your bulbs are blowing so often you need to measure the voltage they're getting. It might be too high.

 

[delmel]

I would still say its a heat issue causing them to blow, it is one of the problems endured by these type of fittings, again especially if left to run for longer periods.

Which capsule lamp have you got loof for the reference

 

[MikeU]

The bulbs are mains voltage, no transformers involved.

The capsules are 40w 240v G9.

 

[Big_Spark]

The most likely causes are going to be the following:

Poor electrical connections in the circuit the lights are fed from:

Poor quality Switch controlling lights causing spiking at On/Off

Devices/Equipment attached to your Installation that are causing transients, spikes or other electrical phenomena that damage lamp elements.


Heat..you say this is unlikely, but coupled to other causes as listed above it will likely be a contributing factor

 

[delmel]

Mike what make are you buying.

I could get you a decent brand prob Osram or Phillips for less

 

[MikeU]

The most recent ones were Crompton.