As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) ABOUT AN HOUR INTO FLIGHT THE R/H DC GEN FAIL ANNUNCIATOR CAME ON, LOSS OF R/H DC GEN WAS CONFIRMED ON AMMETER. AIRCRAFT RETURNED TO BASE WITH NO FURTHER PROBLEMS. MAINTENANCE FOUND THE R/H STARTER GENERATOR HAD FAILED, A QUICK EXAMINATION FOUND A SEGMENT OF THE COMMUTATOR HAD SEPARATED AND IMPACTED THE BRUSHES.