The goal of this master thesis is to compare different model depths of a direct drive wind turbine regarding the generator air gap sensitivity under the gravity’s impact, the magnetic pull and the wind loads in the FEM and MBS. The wind turbine that has been analysed has a rated power of 3.6MW and it works with a nominal speed of 12rpm. The rotor’s diameter is 130m, the hub’s height is 115m and between the ground and the rotor axis there is an angle of 5 degrees. All the parts of the generator are in steel. The mass of the generator is 160tons and the mass of each blade is 27tons.