Abstract: An electric unipolar machine is disclosed which comprises two rotating cylinders disposed one behind the other in an axial direction. The aforesaid rotating cylinders are surrounded by respective stationary cylinders and are connected thereto by sliding contacts.In accord with the invention, a rotor hub which has a central recess and which is divided at a point along the axial direction is provided for supporting the rotating cylinders. The stationary cylinders, in turn, are supported by a housing which is also divided, but along a point in the circumferential direction. In further accord with the invention, the winding of the machine is arranged in the central recess of the rotor hub and is formed as a one-piece ring. Additionally, the winding is supported by means extending through the parting gap of the divided housing and is aligned and fastened by bolts distributed around the circumference of the housing.