Generator, in particular for a wind turbine

1. A generator, comprising:

a stator comprising a plurality of axially spaced induction coils;

a rotor rotatable around the stator, comprising one or more permanent magnets arranged in circumferential direction; and

at least one airduct for guiding an air flow to the stator, comprising radial portions positioned between neighbouring induction coils,

wherein the one or more permanent magnets is/are provided with recesses, each one of the recesses being positioned opposite to one of the radial portions of the at least on air-duct.

2. The generator according to claim 1 , wherein the recesses are shaped such that an axial magnet length at a side facing the stator is smaller than an axial magnet length at the side facing the rotor.

3. The generator according to claim 1 , wherein the recesses have a trapezoidal shape having a longer edge parallel to a shorter edge, wherein the longer edge faces the stator.

4. The generator according to claim 1 , wherein the recesses have a substantially triangular shape.

5. The generator according to claim 4 , wherein the edges of the recesses are formed convex or concave.

6. The generator according to claim 1 , wherein the recesses are formed concave.

7. The generator according to claim 1 , wherein the one or more permanent magnets is/are arranged on a base plate of the rotor.

8. The generator according to claim 1 , wherein the number of the permanent magnets equals the number of induction coils.

9. The generator according to claim 1 , wherein the number of permanent magnets is lesser than the number of airducts.

10. The generator according to claim 1 , wherein the generator is a generator of a wind turbine.