Sealing arrangement for an electric machine, manufacturing method of sealing and sealing method

A method of manufacturing a sealing arrangement for an electric machine, the method comprising:

• forming a plurality of zig-zag sections of a labyrinth seal between a first part attached to a rotatable shaft and a second part configured to be immobile with respect to a stator of the electric machine in a radial direction of the electric machine;
• attaching a second seal to the first part, the second seal comprising an elastic material part for pressing, in the radial direction, against a surface of the second part at a first rotational speed where a centrifugal force acting on the second seal is weaker than an opposing spring force of the second seal, a normal of the surface having a component parallel to the radial direction, and opening a gap between the second seal and said surface at a second rotational speed where the centrifugal force acting on the second seal is greater than the opposing spring force of the second seal;
• including a limiter attached to the first part, the limiter being configured for arrangement at a first position from a rotational axis within the channel of the labyrinth seal, wherein the second seal is configured for arrangement at a second position from the rotational axis within the channel of the labyrinth seal and the first position is farther from the rotational axis than the second position, the limiter being configured to limit a radial movement of the second seal on the basis of the centrifugal force thereby liming a maximum size of the gap;
• and
• providing a gasket seal in the channel of the labyrinth seal between a radial outer end of the labyrinth seal and the second seal.

A method of sealing an electric machine, the method comprising:

• performing first sealing by a plurality of zig-zag sections of a labyrinth seal between a first part attached to a rotatable shaft and a second part configured to be immobile with respect to a stator of the electric machine in a radial direction of the electric machine;
• performing second sealing by a second seal attached to the first part and residing within the channel of the labyrinth seal, the second seal comprising an elastic material part;
• pressing the elastic material part in the radial direction against a surface of the second part at a first rotational speed where a centrifugal force acting on the second seal is weaker than an opposing spring force of the second seal, a normal of the surface having a component parallel to the radial direction;
• opening a gap between the elastic material part and said surface at a second rotational speed where the centrifugal force acting on the second seal is greater than the opposing spring force of the second seal;
• limiting, by a limiter attached to the first part at a position farther from a rotational axis than a position at which the second seal is attached within the channel of the labyrinth seal, a radial movement of the second seal caused by the centrifugal force thereby liming a maximum size of the gap;
• and
• providing a gasket seal in the channel of the labyrinth seal between a radial outer end of the labyrinth seal and the second seal.