Non-halogen incandescant lamps for enlargers are overrated from the start. That means they last much less than household incandescant lamps.
If then you even have higher voltage than those lamps are rated for (as your net runs on the "new" voltage standard and that lamp is still made for the old Standard) that will definitively be too much. For the exact duration in this case I would have to check tables and nomograms though.
As said, check the voltage (in case you have a voltmeter) and the rating of the burnt lamp and report again.