Air gap control in a generator for a wind turbine

An electric generator for a wind turbine is provided including a stator or rotor, the stator or rotor having plurality of winding systems, each winding system covering a respective angular portion of the stator or rotor about an axis of rotation of the electric generator, and a controller for controlling the current flowing in the winding systems. The controller is configured for receiving or determining a thickness of an airgap between the stator and the rotor and controlling the current flowing in at least one of the winding systems so that a respective magnetic radial force is generated, the magnetic radial force acting on the stator and/or rotor for increasing the airgap where the airgap is below a threshold airgap value.