The invention relates to an electrical machine (1, 2, 210) or its use as a wind power generator and a wind power installation having this electrical machine. The electrical machine has a primary part (3, 4, 222, 212, 213) and a secondary part (5, 6, 224), wherein a disc-like primary part (3, 4, 222, 212, 213) and a disc-like secondary part (5, 6, 224) are provided for forming a disc-shaped air gap, or wherein the electrical machine (1, 2, 210) has a cylindrical primary part (3, 4, 212, 213) and a cylindrical secondary part (5, 6, 224) for forming a cylindrical air gap, wherein a primary part, which can be used for a linear motor, is also used for forming the cylindrical primary part (3, 4, 222, 212, 213).