Resistance module for increasing runup torque for a rotor of an electric machine comprising a rotor winding

An exciter for increasing a runup torque for a rotor of an electric machine with a rotor winding, said exciter comprising:

• a secondary winding configured for connection to a shaft of the electric machine in a torsion-proof manner;
• a rectifier connected electrically to the secondary winding;
• and
• a resistance module connected electrically to the rectifier, said resistance module comprising a first connection point, a second connection point, a plurality of electrically-conductive layers electrically connected to the first connection point and to the second connection point, each of the layers surrounding an axis of the resistance module at least partially in a circumferential direction and having a layer start point and a layer end point, at least one of the layers configured in an undulating shape in the circumferential direction, with undulations projecting radially outwards, a first insulating layer disposed between neighboring ones of the layers, a tie point to which the layer end point of one of the layers is electrically connected to the layer start point of a neighboring one of the layers, and at least one fastening element disposed between two neighboring undulations in the circumferential direction and radially outside of the layers.