Causes and inspection methods of frequency converter overload tripping

The motor is probably spinning, but the running current exceeds the rated value, which is called overload. The basic meaning of overload is: the current does exceed the rated value, but the excess is not large, which often leads to a large impact current. The cause and inspection method of inverter overload tripping The emergency of inverter overload is caused by misoperation. There are defects in the current detection part inside the inverter, and the detected current mark is too large, resulting in tripping.

The motor is probably spinning, but the running current exceeds the rated value, which is called overload. The basic meaning of overload is: the current does exceed the rated value, but the excess is not large, which often leads to a large impact current . The cause and inspection method of inverter overload tripping The emergency of inverter overload is caused by misoperation. There are defects in the current detection part inside the inverter, and the detected current mark is too large, resulting in tripping.

Check if the inverter is overloaded. Check if the three-phase voltage on the motor side is balanced. If the three-phase voltage on the motor side is unbalanced, check if the inverter output is balanced. If not, the problem lies with the inverter.

If the inverter output voltage is balanced, the problem lies in the circuit between the inverter and the motor. Check whether all the utility screws of the entire circuit are tightened. If there is a contactor or other electrical appliance between the inverter and the motor, check whether the terminals of the relevant electrical appliances are tightened and whether the contact is in good condition.

Check whether the motor is hot. If the motor temperature rise is not high, check whether the electronic thermal protection function of the inverter is preset correctly. If the inverter is redundant, relax the preset value of the electronic thermal protection function.

If the motor temperature rise is too high and the overload is normal, it means that the motor is overloaded. At this time, should the transmission ratio be appropriately increased to reduce the load on the motor shaft? If so, increase the transmission ratio; if not, increase the capacity of the motor.

The inverter is composed of many electronic parts. The following parts must be replaced regularly. Let us take a look.

1. Replace the relay/contactor

After a certain cumulative number of switching times, relays and contactors may have poor contact and need to be inspected and replaced.

2.Replace capacitor

The intermediate DC circuit uses a large-capacity electrolytic capacitor, and its performance will deteriorate due to the influence of factors such as pulse current. Ambient temperature and usage conditions have a great influence on degradation. The general service life is about 5 years. The capacitor deteriorates rapidly after a certain period of time, so the inspection cycle is one year.

3.Replace the fuse

The rated current of the fuse is higher than the load current. Under normal use, the life of the fuse is about 10 years, so it needs to be inspected, maintained or even replaced within this time.

4. Replace the timer

After a few years of use, the action time of the timer will change greatly, so check the action time and replace it.

That’s all for today, thank you for watching.