An electric machine has a stator, a rotor, and a slip ring module which is connected to a motor shaft of the electric machine. The slip ring module is equipped with at least one wire guiding channel, through which a respective contact wire is guided in order to electrically connect a rotor winding to a slip ring. A first section of the wire guiding channel runs from the slip ring in the axial direction parallel to the motor shaft. A second section of the wire guiding channel runs adjacently thereto radially outwards. An elastic seal element which surrounds the respective contact wire is arranged in or on the second section in order to seal the wire guiding channel to prevent a lubricant from entering the channel.

An electric machine has a stator, a rotor, and a slip ring module which is connected to a motor shaft of the electric machine. The slip ring module is equipped with at least one wire guiding channel, through which a respective contact wire is guided in order to electrically connect a rotor winding to a slip ring. A first section of the wire guiding channel runs from the slip ring in the axial direction parallel to the motor shaft. A second section of the wire guiding channel runs adjacently thereto radially outwards. An elastic seal element which surrounds the respective contact wire is arranged in or on the second section in order to seal the wire guiding channel to prevent a lubricant from entering the channel.

A shaft includes a bushing for a current conductor, and a holder for positioning the current conductor. The holder secures the current conductor in or over an inflection point of a curve of the current conductor.

A wound rotor, such as a wound rotor for an electric machine, includes a shaft having a main axis. The shaft includes a manifold. The wound rotor also includes a winding wire and n poles wound and ordered with an ascending order number obtained by rotation about the main axis. The n wound poles can be distributed radially about the main axis. The n poles are wound with the wire in series in turn according to their ascending order numbers, the last pole, however, not being wound last.

A wound rotor, such as a wound rotor for an electric machine, includes a shaft having a main axis. The shaft includes a manifold. The wound rotor also includes a winding wire and n poles wound and ordered with an ascending order number obtained by rotation about the main axis. The n wound poles can be distributed radially about the main axis. The n poles are wound with the wire in series in turn according to their ascending order numbers, the last pole, however, not being wound last.

A rotor including a rotor shaft, a rotor body formed of a stack of laminations, a field coil wound around the rotor body, and at least one slip ring mounted on the rotor shaft and configured to exchange electric power with an external power supply. Each of the at least one slip ring is configured to be electrically connected to an end of the field coil through an electrical connector. The electrical connector is pre-bended such that to comprise an axial portion and a radial portion respectively located on both sides of a bend, the axial portion being configured to pass through an axial bore of the rotor shaft, the radial portion being configured to pass through a through bore of the rotor shaft.

A method for manufacture of a gold-plated slipring contact, comprising steps of galvanic deposition of a copper layer on the electrically-conductive substrate; of a nickel and/or nickel phosphor layer on the copper layer; and of a gold layer on the nickel and/or nickel phosphor layer. While galvanically applying the copper layer on the substrate, the used galvanic bath explicitly does not include at least one of 3-carboxy-1-(phenylmethyl)pyridinium chloride sodium salt, cationic polymers with urea groups, 1-(3-sulfopropyl)pyridinium betaine, 1-(2-hydroxy-3-sulfopropyl)-pyridinium betaine, propargyl(3-sulfopropyl)ether sodium salt, sodium saccharin, sodium allylsulfonate, N,N-dimethyl-N-(3-cocoamidopropyl)-N-(2-hydroxy-3-sulfopropyl)ammonium betaine, polyamines, 1H-imidazole-polymer with (chloromethyl)oxiran, 3-carboxy-1-(phenylmethyl)pyridinium chloride sodium salt, 1-benzyl-3-sodium carboxy-pyridinium chloride, arsenic trioxide, potassium antimony tartrate, potassium tellurate, alkali arsenite, potassium tellerite, potassium seleno cyanate, alkali antimonyl tartrate, sodium selenite, thallium sulfate, and carbon disulfide, to create the outer surface of the contact that is at least an order of magnitude rougher than a surface of a conventionally-fabricated contact.

A method for manufacture of a gold-plated slipring contact, comprising steps of galvanic deposition of a copper layer on the electrically-conductive substrate; of a nickel and/or nickel phosphor layer on the copper layer; and of a gold layer on the nickel and/or nickel phosphor layer. While galvanically applying the copper layer on the substrate, the used galvanic bath explicitly does not include at least one of 3-carboxy-1-(phenylmethyl)pyridinium chloride sodium salt, cationic polymers with urea groups, 1-(3-sulfopropyl)pyridinium betaine, 1-(2-hydroxy-3-sulfopropyl)-pyridinium betaine, propargyl(3-sulfopropyl)ether sodium salt, sodium saccharin, sodium allylsulfonate, N,N-dimethyl-N-(3-cocoamidopropyl)-N-(2-hydroxy-3-sulfopropyl)ammonium betaine, polyamines, 1H-imidazole-polymer with (chloromethyl)oxiran, 3-carboxy-1-(phenylmethyl)pyridinium chloride sodium salt, 1-benzyl-3-sodium carboxy-pyridinium chloride, arsenic trioxide, potassium antimony tartrate, potassium tellurate, alkali arsenite, potassium tellerite, potassium seleno cyanate, alkali antimonyl tartrate, sodium selenite, thallium sulfate, and carbon disulfide, to create the outer surface of the contact that is at least an order of magnitude rougher than a surface of a conventionally-fabricated contact.

A method for manufacturing a rotor for a slip ring motor, including the steps of: a) arranging a plurality of electric cables inside a hollow shaft, wherein the electric cables are distributed over an inner circumference of the hollow shaft, b) filling a resin into an empty space defined between the hollow shaft and the electric cables, c) arranging a rod inside the hollow shaft thereby displacing the resin into an annular gap between the rod and the hollow shaft, wherein the electric cables are arranged in the annular gap, and d) curing of the resin to form the rotor.

A method for manufacturing a rotor for a slip ring motor, including the steps of: a) arranging a plurality of electric cables inside a hollow shaft, wherein the electric cables are distributed over an inner circumference of the hollow shaft, b) filling a resin into an empty space defined between the hollow shaft and the electric cables, c) arranging a rod inside the hollow shaft thereby displacing the resin into an annular gap between the rod and the hollow shaft, wherein the electric cables are arranged in the annular gap, and d) curing of the resin to form the rotor.