E-20 fault belongs to "current detection" fault, which is caused by the damage of current detection device or circuit fault, DC auxiliary power supply fault, etc. This is generally a hardware fault of the inverter, which needs to be confirmed by the inverter manufacturer or professionals after testing.

Extended data

First, the inverter overcurrent

In the daily use of inverter, the over-current fault rate reported by inverter accounts for about 40-45% of the total number of inverter faults, which is a common high-frequency fault of inverter. As far as the current inverter is concerned, its over-current protection functions mostly include: short-circuit fault (some models are light and heavy); Increase/decrease overcurrent; Constant speed overcurrent, etc.

In the actual use or maintenance process, if the inverter reports overcurrent fault, it should be judged from two aspects:

1. External reasons: This aspect mainly includes motor winding burning driven by frequency converter, cable short circuit on load side and other fault phenomena.

2. Inverter's own reasons: When the current sampling elements in the inverter and the subsequent rectification, shaping and comparison circuits, or the IGBT/IPM power module detects the abnormality of the electronic circuit or the power inverter module itself fails, the inverter will also have an overcurrent fault.

It is not difficult to see that the simplest way to identify the cause of the inverter overcurrent fault is to separate the inverter from the load, and power on the inverter or motor separately for trial operation, so that the cause of the fault will be clear at a glance.

Frequency converter/inverter

Second, the inverter overcurrent phenomenon

The common over-current phenomenon of frequency converter has the following three aspects:

1. An overcurrent fault will be reported when it is powered on. Most of this situation cannot be reset. The main reasons for this situation are: the IGBT/IPM module is damaged, the driving signal is abnormal, and the current detection circuit is faulty. In this case, the inverter must be repaired in time to avoid the fault expansion.

2. The display of the inverter is normal when it is in standby, but it reports the overcurrent fault as soon as it runs. Most of the reasons for this situation focus on the load motor dragging outside the inverter and the mechanical transmission mechanism getting stuck. In this case, it is forbidden to test the machine back and forth with frequency converter without eliminating the problem, otherwise it will not only be a problem of peripheral machinery!

3. The inverter is normal at the initial stage of startup, but it reports overcurrent during acceleration. The main reasons are that the acceleration time of the frequency converter is set too short, the rated current of the motor is set too small to match the reality, the torque compensation (U/F) is set too high, and the parameters are set improperly.