Abstract : This paper describes the abnormal faults such as overcurrent, overload, overvoltage, and undervoltage that occur during the operation of a frequency converter. It analyzes the stored fault information of the frequency converter, identifies the causes, and proposes effective solutions to ensure the frequency converter operates normally under allowable parameters. Keywords: frequency converter , overcurrent, overvoltage, undervoltage, grounding 1 Introduction Frequency converters themselves have rich abnormal fault display and protection functions. If the protection function activates, the frequency converter immediately trips, displays the fault code on the LED, or stores the fault information in a parameter of the program, allowing the motor to run freely until it stops. Before eliminating the cause of the fault and resetting it using the TESET key or the RST input on the control circuit terminal, maintain the tripped state for maintenance and inspection. Inverter faults are divided into two main categories: soft faults and hard faults. Soft faults are often caused by improper operation or parameter settings, while hard faults are caused by damage to the inverter's own components and can be very difficult to repair. Before troubleshooting, carefully review the inverter's operating records before the fault occurred, including current, speed, winding and bearing temperatures, to facilitate fault analysis and inspection. If the inverter displays a certain type of fault, but the corresponding fault does not occur during troubleshooting, carefully check the fault detection components or fault information processing system for problems. [b][align=center]For more details, please click: Protection Functions and Fault Handling of General-Purpose Inverters[/align][/b]