Abstract: The present invention provides a generator comprising winding arrangements, each winding arrangement comprising at least an inner coil and an outer coil constituting a concentric structure of coils. The inner coil is constituted by an inner conductor and the outer coil is constituted by an outer conductor, the inner and outer conductors being connected in series. The inner conductor, which is wound around a tooth, has a smaller electrical resistance per unit length than the outer conductor.

Abstract: Method of repairing a winding in a generator, the generator having a generator rotor and a generator stator, wherein the generator rotor and/or stator comprises a plurality of windings, the windings comprising a stack of turns of a conductor around a tooth, wherein the method comprises cutting the winding on a side of the tooth to separate the winding in two parts; removing the two parts of the winding from the tooth; sliding a substitute partial coil on the tooth, the substitute partial coil comprising a stack of incomplete conductor turns having a first end and a second end, said first and second end positioned on the same side of the tooth; and connecting the second ends of each incomplete turn with a first end of the next incomplete turn using a plurality of conductor portions. The disclosure further relates to a kit for making a substitute coil.

Abstract: Anti-ovalization tool for introduction into a wind turbine blade root comprising two or more rigid bodies connected to one another along their side edges with distances in between them and together forming a substantially cylindrical body, wherein the distances between the rigid bodies are adjustable. The invention is further related to the method of reducing ovalization of a wind turbine blade root and to the use of a tool comprising two or more rigid bodies as an anti-ovalization tool.

Abstract: A method of calibrating one or more load sensors of a blade of a wind turbine, said wind turbine comprising a main generator, a power electronic converter connected with the main generator, and a rotor operationally connected with the main generator and carrying the blade. The method comprises acting on the power electronic converter to operate the main generator as motor to set the blade in at least one predetermined condition. The method further comprises measuring loads in the predetermined condition using the load sensors of the blade and calibrating the blade load sensors taking into account the measured loads.