With the development of power electronics technology and the transformation of a large number of industrial infrastructure equipment, more and more users have put forward higher requirements for electrical equipment in the field of control. The emergence and application of inverter brands have simplified complex control and made the production process more convenient, fast and accurate. However, like other control equipment, inverter brands of inverters will inevitably have failure problems in application. In order to reduce losses, the type and cause of the failure must be found out as soon as possible. Today, the editor has sorted out the common problems in the daily operation of the inverter and the corresponding inspection methods, hoping to be helpful to you.

1、Overcurrent fault

Overcurrent faults can generally be divided into acceleration, deceleration and constant speed overcurrent. The main reasons are too short starting acceleration time, sudden increase in load, inverter output short circuit, uneven load distribution, inverter and motor capacity mismatch, internal rectifier or inverter side component damage, power supply phase loss, output disconnection, motor internal fault, grounding fault, etc.

For overcurrent faults, the maintenance method is as follows: When checking the fault, the load should be disconnected first and the inverter should be checked. If the overcurrent fault still exists after disconnecting the load, it indicates that the internal components of the inverter are faulty and further inspection and maintenance are required.

For these faults, corresponding measures can be taken: extend the acceleration time, design the load distribution, check the line, prevent interference and mechanical vibration, and reduce load mutations.

2、Overvoltage fault

Inverter overvoltage fault refers to the inverter overvoltage tripping when the DC bus voltage of the unit exceeds the rated value. The main causes of the unit overvoltage fault are: first, the high-voltage power supply on the input side exceeds the maximum allowable value; second, the overvoltage tripping of the inverter is caused during the deceleration process. Inverter brand inverter overvoltage faults include overvoltage when inputting the compensation capacitor, lightning overvoltage, overvoltage when the braking or deceleration time is too short, power supply overvoltage, etc.

After the fault occurs, first check whether the input power supply voltage is stable, whether the motor starts when idling, and whether there is external force dragging. On the premise of confirming that the input power supply voltage is stable, add an absorption device on the power input side to reduce the overvoltage factor. When there is an impact overvoltage, an overvoltage caused by lightning, and an overvoltage formed when the compensation capacitor is closed or disconnected on the power input side, it can be solved by connecting a surge absorption device in parallel on the input side or a series reactor.

Overvoltage faults usually occur during shutdown and are related to the intermediate circuit and braking link. The main reason is that the braking resistor is damaged or the deceleration time is too short. Therefore, the solution is to increase the deceleration time parameter or add a braking resistor (brake unit).

3、Undervoltage fault

The inverter undervoltage fault means that the main circuit voltage is too low, such as 220V series is lower than 180V, 380V series is lower than 300V. It is generally caused by power phase loss, too many inverters working or starting at the same time, damage to the thyristor of the DC circuit current limiting resistor of the inverter or short circuit of the current limiting resistor, external interference or interference between inverters.