... Max. Efficiency≥92%* Perfect protection and warning functions* Low Frequency Transformer, which ensures that inverter has high efficiency and ... under voltage, overvoltage, over temperature, over-current, short circuit, etc.Cooling methodFan-cooledNoise<55dBDegree of protectionIP20(indoor)Using altitude ... , EN61000-3-12:2005, EN61000-3-11:2000 Low frequency sinlge phase to three phase off grid inverter ...