Abstract: An electrical machine (50) comprising a rotor (70), a stator (60), a stator cooling system (80) including stator cooling channels (66) conducting cooling fluid to active parts of the stator (60), and a rotor cooling system (90) for cooling active parts of the rotor (70) is provided. The rotor cooling system (90) is configured to provide a rotor cooling gas flow, and the rotor cooling gas flow is cooled by the stator cooling channels (66). Methods for cooling electrical machines (50) are also provided, as well as wind turbines comprising generators with cooling systems.

Abstract: In a first aspect, a method of performing maintenance operations in an electrical machine is provided. The method comprises positioning the rotor in a first position; disconnecting electrical windings, removing one or more segments of an electrical conductor ring and positioning the rotor in a second position without connecting the removed segments of the electrical conductor ring. In a further aspect, a method of operating an electrical machine is also provided. In yet a further aspect, it is provided an electrical machine comprising an electrical conductor ring having a releasable segment.

Abstract: In a first aspect, a method of performing maintenance operations in an electrical machine is provided. The method comprises positioning the rotor in a first position; disconnecting electrical windings, removing one or more segments of an electrical conductor ring and positioning the rotor in a second position without connecting the removed segments of the electrical conductor ring. In a further aspect, a method of operating an electrical machine is also provided. In yet a further aspect, it is provided an electrical machine comprising an electrical conductor ring having a releasable segment.