What was found
AT BEGINNING OF TAKEOFF ROLL NR 3 GENERATOR TRIPPED OFFLINE WITH OVERVOLTAGE. RAN QRH CHECKLIST TO DISCONNECT CSD SUCCESSFULLY. RAN REJECTED TAKEOFF CHECKLIST (QRH) . TRIED TO CONNECT GENERATOR UNSUCCESSFULLY PRIOR TO DISCONNECTING CSD. NR 3 CSD DISCONNECTED. RT PACK FAN IS DEACTIVATED. OPERATED RIGHT PACK IN FLIGHT ONLY AND ONLY WITH GEAR UP AND FLAPS UP. CONNECTED NR 3 CSD. NR 3 RAN NR 2 AND NR 3 ENGINE IAW JRH. PARALLELED 2 & 3 BUSS TIES. WHEN ADVANCING ENGINES SLIGHTLY, BOTH BUSS TIES TRIPPED. R & R NR 3 GCU NR 3 GEN SYSTEM OPS CHECKS GOOD. AMM 20-10-017-2, AND 24-20-000-5.