How to eliminate the soft fault of the inverter

1, overcurrent

Overcurrent is the most frequent phenomenon of inverter alarms.

1.1 phenomenon

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

(2) Jumping on power-on, this phenomenon can't be reset generally. The main reasons are: bad module, bad drive circuit, and bad current detection circuit.

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

2, overpressure

Overvoltage alarms generally occur when the machine is stopped. The main reason is that the deceleration time is too short or there is a problem with the braking resistor and the brake unit.

3, undervoltage

Undervoltage 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: a certain damage of the rectifier bridge or abnormal operation of the thyristor three-way may cause undervoltage faults. When it occurs, the secondary circuit contactor is damaged, which causes the DC bus voltage loss to cause undervoltage on the charging resistor. There is also a problem that the voltage detection circuit is faulty and undervoltage occurs.

4, overheating

Overheating is also a common fault. The main reasons are: the surrounding temperature is too high, the fan is blocked, the temperature sensor performance is poor, and the motor is overheated.

5, the output is unbalanced

The output imbalance is generally characterized by motor jitter and unstable speed. The main reasons are: bad module, bad drive circuit, and bad reactor.

6, overload

Overload is also one of the more frequent faults of the inverter. When we see the overload phenomenon, we should first analyze whether the motor is overloaded or the inverter itself is overloaded. Generally speaking, the motor has strong overload capability, as long as the motor of the inverter parameter table The parameters are set properly, generally no motor overload occurs. The inverter itself is prone to overload alarm due to poor overload capability. We can detect the inverter output voltage, current detection circuit, and other fault-prone points to eliminate faults.