I will present my research on “Feasibility study and optimal design of a 10MW air-core fully SC machine for offshore wind turbine”. This machine design is considered with armature coils inside and rotating field coils outside. In this topology, shield iron is eliminated or reduced by replacing it with shield coils which contain the magnetic flux within the machine. This machine is attractive for off-shore wind turbine application due to its high-power density and high efficiency compared to the conventional shield iron designs. However, this design uses relatively higher SC material than the conventional shield iron design due to the additional shield coils placed on the outer rotor. An optimal design scheme of combination between shield coils and shield iron will be discussed in the presentation. A detailed ac loss calculation will be discussed with the required cryocooler power and efficiency calculation.