Clean the cooling air duct and internal dust of the air filter.Check if screws,bolts,and connectors are loose,and if there is a short circuit in the ground and phase resistance of the input and output reactors.Normally,it should be greater than tens of megaohms.Conductors and insulators should be wiped clean with alcohol in a timely manner.If conditions permit,use an oscilloscope to measure the stability of the output voltages of the switching power supply,such as 5V,12V,15V,24V,etc.Measure whether there is distortion in the square wave of each waveform of the driving circuit.Is the UVW phase to phase waveform a sine wave.
　　Check if there are any signs of ignition on the contacts of the contactor.In severe cases,replace them with new products of the same model or larger than the original capacity;Confirm the correctness of the control voltage and conduct a sequential protection action test;Confirm that there are no abnormalities in the protection display circuit;Confirm the balance of the output voltage of the variable frequency power supply when operating separately.
　　It is recommended to conduct regular inspections,which should be conducted once a year.
　　Replacement of spare parts for variable frequency power supply
　　The variable frequency power supply is composed of multiple components,some of which will gradually decrease and age in performance after long-term operation,which is also the main reason for the failure of the frequency converter.In order to ensure the long-term normal operation of the equipment,the following components should be replaced regularly:
　　1.Filter capacitor
　　Intermediate circuit filtering capacitor:also known as electrolytic capacitor,its main function is to smooth the DC voltage and absorb low-frequency harmonics in the DC.The heat generated by its continuous operation,combined with the heat generated by the variable frequency power supply itself,will accelerate the drying of its electrolyte,directly affecting its capacity.Under normal circumstances,the service life of a capacitor is 5 years.It is recommended to regularly check the capacitor capacity once a year.Generally,if the capacity is reduced by more than 20%,it should be replaced.
　　2.Cooling fan
　　The power module of a variable frequency power supply is the most severely heated component,and the heat generated by its continuous operation must be discharged in a timely manner.The lifespan of a typical fan is approximately 10Kh-40Kh.According to the conversion of continuous operation of variable frequency power supply,the fan needs to be replaced every 2-3 years.There are two or three wires for direct cooling fans.One wire of the two wire fan is the positive pole,and the other wire is the negative pole.When replacing,do not connect it incorrectly;In addition to the positive and negative terminals,there is also a detection wire for the three wire fan.Be careful when replacing it,otherwise it may cause an overheating alarm for the variable frequency power supply.AC fans are generally divided into 220V and 380V.When replacing them,do not make mistakes in voltage levels.