A ring generator of a wind power installation is provided comprising a stator having a peripherally extending stator ring for receiving stator windings and a rotor mounted rotatably about an axis of rotation relative to the stator, wherein the stator ring has cooling passages for cooling the stator by an air flow. A ring generator of a wind power installation is also provided having a stator, a peripherally extending stator ring for receiving stator windings, a rotor mounted rotatably relative to the stator and a stator bell connected to the stator ring for providing a pressure chamber with an increased or reduced pressure for providing an air flow through and/or along the stator and/or rotor for cooling the ring generator, wherein the stator bell has at least one fan opening provided with a fan.