1. As maintaining the bridge girder launcher, the operator must directly confirm that the frequency converter input power supply is in the state “cut off” 2. After cutting off the power bridge girder launchersupply, high voltage electricity may still be remained in main circuit electrolytic capacitor of the frequency converter 3. After confirming releasing remained voltage, the machine can be operated. Steps for reference: cut off power supply---wait for 5-10 minutes, rechargeable lights go out--- measure DC filter capacitor voltage < 36V with multimeter---maintain the frequency converter 4. As directly measuring output voltage of the frequency converter, rectifier type AC voltage meter must be used. As using the frequency converter, watch the followings everyday: Whether cooling system works well, vibration condition and frequency converter and its surrounding heating condition Regular inspection content: 1. Whether the screw is tight or rust because of environment, if it is, immediately tighten the screw or change it 2. Whether foreign matters fall in the frequency converter or on the heating panel, if it does, clean them using compressed air. 3. Carefully check whether print wire connection panel is in good contact condition, bad products should be changed immediately. Frequency converter is not suitable for any condition, to use it, you must learn more about load, environmental demand and frequency converter itself. Load type and frequency converter selection. Load driven by motor is different, the demand on the frequency converter is also different.