What was found
DURING TAKE OFF ROLL, GENERATOR DROPPED OFF LINE FOLLOWED BY NR 3 GEN LIGHT. REJECTED TAKE OFF AT 75 KNOTS. ACCOMPLISHED AOM PROCEDURE GENERATOR CHECKLIST ZA9-1 AND REJECTED TAKEOFF. RETURNED TO GATE WITHOUT INCIDENT. FOUND NR 3 GENERATOR FREQUENCY FLUCTUATING. TRANSFERRED TO DMI 6159 IAW MEL 24-1 PLACARDS INSTALLED AND DISCONNECTED NR 3 CSD. AIRCRAFT RETURNED TO SERVICE. REMOVED AND REPLACED NR 3 GENERATOR AND CSD IAW MM. OPS CHECK AND LEAK CHECK GOOD ON ENGINE RUN. CLEARED DMI 6159.