Ceiling Fan stopped working ? Any Ideas ?

Hi, I hope someone can shed some light on this as it is driving me insane ! I have fitted a ceiling fan/light in my conservatory and after a few hours of the fan being turned on it has stopped working. I got the electrician back to look at it and he informed me that no power was going into the fan? The fuse connected to the electrical circuit had not blown as the light was still working but the fan was dead. I took it back to the shop, got a replacement and again the same thing happened and again took it back and so on, this morning the third fan that has been installed has gone again? Why does this keep happening ?? I have since bought a competely different fan from a different store to see if the same happens, but before i get it installed i require extra advice ?? any welcome thanks