What was found
ON FLT 510 - ATL-BNA - AIR RETURN, AT 20,000 FEET THE LEFT GENERATOR TRIPPED WITH A/C X-TIE LOCK OUT, RESET GENERATOR, VOLTS AND FREQS NORMAL, BUT TRIPPED AGAIN WHEN PUT ON LINE. CHECKED LEFT ENGINE GENERATOR CABLE FROM GENERATOR TO RELAY, CHECKS OK. RAN ENGINES PERFORMED CROSS TIE CHECK, OPS CHECK GOOD PER MM 24-20-00. (M)