... )super wide input voltage range from 90v to 280v 2)4 steps AVR, 220v+_10% 3)super wide input frequency range from ... kinds of great frequency generator,such as diesel engine .etc.4) protections against output short-circuit, overload protection ( when it is ... , wind generator, solar system and so on,8) 4 steps AVR, 220v+_10%, three steps to increase the voltage, one step to recrease ...