(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.
Yaskawa Inverter failure (2) Power on jump, this phenomenon generally can not be reset, the main reasons are: bad module, bad drive circuit, current detection circuit is bad.
Yaskawa inverter fault how to eliminate inverter soft fault analysis, (3) does not immediately trip when restarting but in acceleration, the main reasons are: too short acceleration time setting, current limit is too small, torque compensation (v/ f) The setting is higher.
Inverter > The inverter jumps "oc" as soon as it starts
Analysis and maintenance: Open the lid did not find any signs of burnt, online measurement igbt (7mbr25nf-120) basic judgment is no problem, in order to further determine the problem, after removing the igbt measured 7 units of high-power transistor opening and closing both well. When measuring the drive circuit of the upper half bridge, it was found that there was a clear difference between the other two circuits. After careful inspection, it was found that the output pin of the optocoupler a3120 had a short circuit with the negative electrode of the power supply. After the replacement, the three paths were basically the same. The module is powered on and everything is running fine.
Analysis and maintenance: First check the inverter module found no problems. Secondly, there is no abnormality in checking the drive circuit. It is estimated that the problem is not in this block. It may be in the part of the over-current signal processing. After the circuit sensor is removed and the power is turned on, it shows that everything is normal. Therefore, the sensor is considered to be bad and a new one is needed. After loading the experiment, everything was normal.
2, over pressure
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.
When the frequency converter decelerates, the motor rotor windings cut the rotating magnetic field faster, the rotor's electromotive force and current increase, the motor is in the state of power generation, and the feedback energy passes through the diode in parallel with the high-power switch tube in the inversion link to the DC link. Cause the DC bus voltage to rise, so we should focus on checking the brake circuit, measuring the discharge resistance is no problem, in the measurement of the brake pipe (et191) was found to have broken down, after the replacement of power running, and there is no problem with the fast stop .
3, under pressure
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: a rectifier bridge damage or SCR three-way work may lead to undervoltage fault 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.
Inverter charging circuit does not use thyristor but by the contactor to complete the charging process, so that the fault may be in the contactor or control circuit and power supply part, remove the contactor and add 24V DC contactor work alone normal. Then check the 24v DC power supply, after careful inspection of the voltage is regulated by the lm7824 regulator after the output, measuring the regulator has been damaged, find a new replacement after the power is working properly.