Wirnik

Wirnik is the rotating component of a machine in which mechanical energy is transmitted or transformed during operation. In electrical machines such as motors and generators, the wirnik carries windings or magnetic poles that interact with the stator’s magnetic field to produce torque or induce voltage. The term originates in Polish and is widely used in Polish engineering literature; in English, the corresponding element is typically called the rotor.

Rotor types in electric machines include the wound rotor, where windings on the rotor are connected to external circuits via slip rings and brushes; the squirrel-cage rotor, consisting of conductive bars short-circuited by end rings; and permanent-magnet rotors, which place magnets on the rotor to create the magnetic field. Wound rotors offer controllable starting torque through external resistance, while squirrel-cage rotors are known for simplicity and ruggedness.

Most rotors are built from laminated electrical steel to reduce eddy current losses; they are mounted on a shaft and may include a balancer, end shields, cooling paths, and bearings. In induction motors, the rotating field from the stator induces current in the rotor, producing torque only when there is slip between the rotor speed and the stator field.

Beyond electric machines, the term wirnik also appears in turbomachinery and aviation, where the rotor denotes the rotating assembly of a turbine or a hub-mounted propeller. In gas and steam turbines, the rotor includes disks and blades attached to a shaft and designed to withstand high speeds and temperatures.

See also: rotor, stator, turbine rotor, electric motor.