The invention concerns a generator for a windmill. The generator is of the kind being directly coupled to the main shaft of the wind rotor of the windmill. The generator is a stator consisting of a number of stator modules that are individual and which may be installed, repaired and dismantled individually and independently of each other. This implies that it is very easy and thereby cheaper to mount the mill, especially at sea, as the stator for the generator can be transported in smaller units, which also makes it easier to assemble the stator in the tower top section. By sequent repairs and other maintenance of the generator it is not necessary either to use large cranes, but it is sufficient to use smaller hoisting devices that may be handled by one or two persons.