AN MD80 IN CLB AT FL260 DIVERTED DUE TO 'AC X-TIE LOCKOUT' WARNING LIGHT; CAPT'S PARTIAL INST FAILURE WITH 'L GENERATOR INOP' WITH 'L FEEDER FAULT.' CAUSED BY FAILED L GENERATOR.

Narrative

FLT WAS ENRTE TO OAK WITH EVERYTHING NORMAL. CLBING THROUGH FL260 FOR FL330 (CAPT FLYING); WE GOT THE 'AC X-TIE LOCKOUT;' 'L GENERATOR INOP' AND 'L GENERATOR FEEDER FAULT' LIGHTS ALL ON AT ONCE. I LOST SOME OF MY FLT INSTRUMENTATION AND GAVE CTL OF THE ACFT TO THE COPLT AND SELECTED #2 DFGC. I RAN THE QRH FOR THE 'AC X-TIE LOCKOUT' AND STARTED THE APU WHILE THE COPLT GOT CLRNC TO LEVEL AT FL280. THE L GENERATOR WOULD NOT RESET AND SHOWED ZERO FREQ AND VOLTS; BUT THE APU TOOK OVER THE L BUSSES AND WE RESTORED PWR TO ALL THE BUSSES. WE TRIED TO PATCH MAINT CTL AND DISPATCH THROUGH ZZZ OPS; BUT WERE NOT ABLE TO; SO HAD ZZZ OPS AND MAINT PASS OUR INFO TO MAINT CTL AND DISPATCH. WITH THE 'FEEDER FAULT' LIGHT STILL ON; WE DECIDED TO RETURN TO ZZZ AS A PRECAUTION. WE TALKED TO THE FLT ATTENDANTS WHEN THE GENERATOR FIRST FAILED AND THEN AGAIN ABOUT 5-8 MINS AFTER THE OCCURRENCE; TO LET THEM KNOW THAT WE WERE RETURNING TO ZZZ; BUT WERE NOT EXPECTING AN EMER OR EVAC. ABOUT 15 MINS AFTER ARRIVING AT THE GATE (PAX HAD ALREADY DEPLANED); THE CREW DID A 'DEBRIEF' AND IT WAS APPARENT THAT THE FLT ATTENDANTS WERE SICK AND SEVERAL WERE ACTUALLY ON OXYGEN. THEIR SYMPTOMS SEEMED CONSISTENT WITH AN AIR QUALITY INCIDENT AND THEY WERE STARTING TO FEEL WORSE; NOT BETTER. THE EMT'S WERE CALLED AND THEY ARRIVED AND ASSESSED THE FLT ATTENDANTS. AN AMBULANCE WAS CALLED AND THE 3 FLT ATTENDANTS AND MYSELF WENT TO THE HOSPITAL EMER ROOM. THEY WERE SEEN BY A DOCTOR. THE PLTS DID NOT FEEL ANY SYMPTOMS NOR DID WE SMELL ANY FUMES OR ODORS; BUT THERE ARE MANY VARIABLES THAT AFFECT PLTS AND FLT ATTENDANTS DIFFERENTLY (ACTIVE UP AND DOWN THE AISLES VERSUS SITTING; POS IN THE ACFT; YAW; ETC). I BELIEVE THE FLT ATTENDANTS' SYMPTOMS WERE VERY REAL; BUT DO NOT HAVE A GOOD EXPLANATION FOR THE 'AIR QUALITY' TYPE SCENARIO. I MIGHT ADD THAT THE FAILED GENERATOR GOT SO HOT THAT PART OF THE CASING ACTUALLY MELTED.