... is mainly applicable to a power system of AC 50Hz(or 60Hz),rated working voltage up to ... 230V,and in a line of application class AC-7a with rated working voltage up to 230V and rated ... AC-1,AC-7a,AC-7b) rated working voltage(V): 230(AC-1,AC-7a,AC-7b) conventional heating current(A): 20(AC-1,AC-7a,AC ... -7b) control power(KW): 4(AC-1,AC-7a ...