A wind power generator with a closed internal cooling circuit has a stator that is implemented as sheet metal and includes a winding system which forms winding heads at the end faces of the stator. The stator is enclosed by a cooling jacket at least in the region of the laminated core, wherein permanent magnets of a rotor are disposed on a magnet wheel jacket embodied as a hollow shaft. The magnet wheel jacket is connected in a rotationally fixed manner to a shaft or shaft stubs by way of support elements at its end faces, wherein in its interior the hollow shaft has at least one tube whose lateral surface area runs at an equidistant clearance from the magnet wheel jacket. Blowers are mounted at the end faces of the rotor.