... class H insulation ex-factory test report AC three phase, self-excited, brushless POWER WORLD V series environment ... Marathon, ENGGA brushless alternator) 3 Phase 4 Wire, Brushless, H class Insulation, Self-Exited ,IP23 Protection, AVR regulation, Voltage deviation: ±0 ... .5%, THF<5%,low radio interference.3) Frequency: 50 & 60Hz4) 3 Phase 4 Wire5) ...