What was found
PHL - FLT 162 - SHORTLY AFTER T/O, THE NR 1 TRANSFORMER RECTIFIER C/B TRIPPED FOLLOWED BY THE BATTERY CHARGER AND THE 'B' SYSTEM ELECTRIC HYDRAULIC PUMP. WITHIN 10 MINUTES, THE NR 1 ELECTRIC BUS TRIPPED FOLLOWED BY THE AC STANDBY BUS, EQUIPMENT COOLING NORMAL BLOWER AND FCC DC BREAKER AND THE NR 2 TRANSFORMER RECTIFIER. FLIGHT RETURNED TO FIELD AT PHL AND LANDED WITHOUT FURTHER INCIDENT. NO EMERGENCY WAS DECLARED. THE APU WAS ON MEL AT THE TIME. MAINTENANCE REMOVED AND REPLACED THE NR 1 GENERATOR CONTROL BREAKER C801. RAN ENGINES FOR EXTENDED TIME TO CHECK NR 1 GENERATOR AND RELATED SYSTEMS. OPS CHECKED GOOD. (M)