Abstract: The invention concerns an asynchronous machine having a slip-ring rotor for use with a variable rotational speed, with a rotor, a rotor body, having grooves mounted radially into the rotor body, winding elements of the rotor, from which respectively at least one element runs axially through each of the grooves, locking elements, which co-operate in a form fit manner with the rotor body and close the grooves radially and outwardly, a high voltage insulation with outer corona protection around each of the winding elements. The invention is characterised in that between the outer corona protection of the winding element and at least one neighbouring wall of the groove in peripheral direction electrically conducting connecting means are arranged for releasable connection of the winding element with the rotor body.