Holding apparatus for a slip ring unit, slip ring bridge, slip ring unit, electric machine, and wind turbine

A slip ring unit, comprising:

• a slip ring having peripheral surface and including a contact surface on the peripheral surface;
• a holding apparatus including at least two slots configured for insertion of slip ring brushes respectively, said at least two slots being arranged in spaced-apart relationship and oriented such that the slip ring brushes are oriented orthogonally with respect to the peripheral surface, in particular with respect to the contact surface of the slip ring, said holding apparatus comprising a cooling duct arranged between the at least two slots for cooling a side surface of the slip ring brushes, said cooling duct being configured as a third slot between the at least two slots, with the at least two slots and the cooling duct being of essentially identical shape and dimension;
• and
• a slip ring bridge comprising a bow-shaped base element for attachment of the holding apparatus,
• wherein the contact surface of the slip ring is formed with a recess to enable an airflow in a radial direction through the cooling duct of the holding apparatus, in particular when the slip ring rotates, for cooling a side surface of the slip ring brushes.