A method and a device with a control apparatus (50) for starting an electric machine (10) with a rotor (20), particularly the spinning cup of an open-end spinning machine, magnetically mounted by a bearing having permanent magnets (31, 32, 33, 34). An actuator system controls the position in the axial direction (35, 36) and two limitation bearings (41, 42), determine the axial end positions of the rotor. The actuator system brings about a lifting from the first axial end position, and a system variable during such lifting is compared with a reference value, and the rotor (20) is moved into the second end position, and the actuator system brings about a lifting from the second axial end position, and a system variable on lifting from the second end position is compared with a reference value.