Bulbs always blowing

[peteelecs]

I have 3 sets of 4 plate spotlights they are SES 40W R50 and the bulbs are always blowing after a couple of weeks (not all at the same time) any ideas would be appreciated

 

[nickblake]

there are a few reasons 1 cheap un branded lamps , lamps that have been mis treated thrown about abit when in transit , mounted to a ceiling where there is heavy traffic , kids running over the area when the lights are on ,when the lamps are hot the filament is fragile , or it could be a faulty lamp holder where the contacts are worn , even a cold area where the lights are switched on and the sudden change of temperature ruptures the filament , way round it is low energy lamps

 

[MFHEng]

Just a couple of questions to go through first

1 what is the actual opperating voltage of the lamps? some lamps sold are 220volts (as there cheap)
2 What is the measured voltage of the supply? you may have a high voltage ( 240+ which has an impact on the lamps if they are rated at 220 volts)
3 What is the quality of the lamps your using ? (see question 1)
4 Where is the installation, out in the sticks or in a town etc - if in the sticks the transformer might be tapped high to account for voltage drop further down the line and could give the initial customers upto and in excess of 253 volts ( which is an issue if the lamp voltage in question 1 is low)

 

[andyb]

Any of the above & check the voltage, too high & this will shorten bulb life.