Application QZB series auto-transformer is applied to three-phase squirrel cage induction motor of AC50Hz,rated voltage 380V,rated capacity up to 400kW,as reducing voltage to start under the condition of unfrequent start. This production conforms to standard of GB14048.4 and JB/T8752. control motor power kW code:K for with temperature protection switch,non for without temperature protection transformer auto-transformer voltage reduce starting Normal operational condition 3.1 Altitude: up to 2000m. 3.2 Ambient temperature:-5C to +40C.Average day temperature:up to +35C. 3.3 Max temperature:+40C. Max humidity: 50%. The higher temperature is acceptable in the lower temperature,like the 90% is acceptable under +20C,but the condensation caused by temperature change should be taken care. 3.4 Location should have no explorsion danger medium,and als has no metal -corrosion and insulation-damage gas and dust. 3.5 Angle of install and horizontal plane should not exceed 5 and location should have no obvious vibration and impact,and no rain and snow. Characteristic 4.1 rated operational voltage is AC380V,50Hz,output connecting is 100% terminal 4.2 it is single coil transformer.first and secondary side is using same winding.the transformer radio is fixed. 4.3 When It is short-time duty or intermittent work period,For avoid the Overheating burn of abusing,the temperature protection switch(thermal switch) will be installed in QZB-K series transformer coil. 4.4 All kinds of working type,first starting time of auto-transformer would not exceed 15 seconds.