Analysis of common faults of frequency converter

With the increasing application of variable frequency speed regulation technology in my country's cement industry, it has become an inevitable trend to replace voltage regulation, slip regulation and DC speed regulation with AC variable frequency speed regulation in many links of production processes that require speed regulation, such as rotary kilns, grate coolers, feeders, batching scales, fans, water pumps, etc.

The inverter contains a large number of electronic components, each of which plays a vital role.

Internal components of the inverter

According to the function, it is divided into main circuit, auxiliary switching power supply, control board and driver board.

Analysis of common faults of frequency converter

(1) Overcurrent fault: Overcurrent fault can be divided into acceleration, deceleration, and constant speed overcurrent. It may be caused by too short acceleration and deceleration time of the inverter, sudden load change, uneven load distribution, output short circuit, etc. At this time, it can generally be solved by extending the acceleration and deceleration time, reducing sudden load changes, adding energy-consuming braking elements, designing load distribution, and checking the circuit. If the inverter still has an overcurrent fault after disconnecting the load, it means that the inverter inverter circuit has looped and the inverter needs to be replaced.

(2) Overload fault: Overload fault includes frequency conversion overload and motor overload. It may be caused by too short acceleration time, too low grid voltage, too heavy load, etc. It can generally be solved by extending the acceleration time, extending the braking time, checking the grid voltage, etc. The load is too heavy, the selected motor and inverter cannot drag the load, or it may be caused by poor mechanical lubrication. In the former case, a high-power motor and inverter must be replaced; in the latter case, the production machinery must be repaired.

(3) Undervoltage: This indicates that there is a problem with the inverter power input part and it needs to be checked before it can be operated.