Amortisseur or damper windings. Amortisseur (damper) windings are special bars laid into notches carved in the rotor face and then shorted out on each end by a large shorting ring.
A rotor of large synchronous machine with a brushless exciter mounted on the same shaft. Many synchronous generators having brushless exciters also include slip rings and brushes to provide emergency source of the field DC current.
