How to avoid frequency converter soft fault

Inverter soft fault is one of the common faults that exist in the operation of various types of inverters. So how can we reduce the frequency converter soft fault? This is a problem that all inverter manufacturers and users are very concerned about. The specifics will be introduced below.

The methods for reducing soft faults of frequency converters include: 1. Detecting over-voltage and under-voltage of the frequency converter; 2. Detecting over-current is the most frequent phenomenon of frequency conversion alarm.

In general, overvoltage alarms usually occur at the time of shutdown. The main reason is that the deceleration time is too short or there is a problem with the braking resistor and the brake unit. Underpressure is also a problem we often encounter in use. Mainly because the main circuit voltage is too low (220V series is lower than 200V, 380V series is lower than 400V). The main reason is that any damage to the rectifier bridge or abnormal operation of the SCR three-way circuit may cause undervoltage faults. Appeared, followed by the main circuit contactor damage, resulting in DC bus voltage loss above the charging resistor may cause undervoltage. There is a voltage detection circuit failure and undervoltage problems.

The over-current phenomenon mainly manifests as follows:

(1) When restarting, it will trip at a raise speed. This is a very serious phenomenon of overcurrent. The main reasons are: load short circuit, mechanical parts stuck; inverter module damage; motor torque is too small and so on.

(2) Power-on jump, this phenomenon can not be reset generally, the main reasons are: bad module, bad drive circuit, bad current detection circuit.

(3) When restarting, it does not immediately trip, but when accelerating, the main reasons are: too short acceleration time setting, too low current limit setting, and high torque compensation (V/F) setting.