What was found
FLIGHT 3699, GENERATOR 2 CAUTION MESSAGE AFTER TAKEOFF. FOLLOWED QRH GENERATOR 2 WOULD NOT RESET. DURING RESET ATTEMPT AC ESS BUSS NR 2 FAILED-AUTO TRANSFER FAILED AND APU GEN WOULD NOT PICK UP LOAD. COULD NOT GET AC ESS BUSS NR 2 BACK ONLINE. AIR RETURNED AND AN EMERGENCY DECLARED. DISCONNECT BATTERIES TO RESET ELECTRICAL SYSTEM INSPECTED NR 2 IDG AND FOUND OIL LEVEL LOW. SERVICED NR 2 IDG IAW AMM 12-13-24. RECONNECTED BATTERIES SYSTEM RESET IAW AMM 24-00-00. PERFORMED ENGINE RUN AND OPS CHECK WITH FLIGHT CREW IAW AMM 24-11-01. OPS NORMAL NO LEAKS NOTED.