Overload trip of frequency converter is one of the common problems in the operation process of blowing machine. The overload trip of the frequency converter should be treated by scientific and effective methods. This article will introduce the reasons and solutions of the inverter overload trip in detail.
What is the blowing machine inverter overload?
The motor can rotate, but the running current exceeds the rating, which is called overload. The basic reflection of overload is that although the current exceeds the rated value, it does not greatly exceed the rated value, and generally will not form a large impact current.
What is the reason of overload trip of blowing molding machine inverter?
There are mainly three reasons:
1.The wrong behavior of the current detection part of the frequency converter fails, and the detected current signal is too large, resulting in the trip.
2. The main feature of large overload of mechanical load is the motor heating, which can be found by reading the running current from the display screen.
3. Three-phase voltage imbalance leads to excessive operating current of a certain phase, leading to overload trip. It is characterized by an uneven heating of the motor, and may not be found when reading the running current from the display screen (because the display screen displays only a one-phase current). Find out the reason to think about the inverter overload processing method.
How to deal with the overload trip?
1. Check whether the three-phase voltage on the motor side is balanced if the three-phase voltage on the motor side is unbalanced, check the three-phase voltage on the output side of the inverter again. If it is also unbalanced, the problem is inside the inverter. The inverter module and drive circuit of the inverter should be checked. If the voltage output of the inverter is balanced, the problem is in the circuit between the frequency converter and the motor, check whether the bolts at all wiring ends are tightened. If there is a contactor or other electrical appliances between the frequency converter and the motor, check whether the wiring terminals of the related electrical appliances are tightened and whether the contact point is in good condition. If the three-phase voltage on the motor side is balanced, the operating frequency during the trip should be known. If the operating frequency is low and there is no vector control (or no vector control), then the U / F ratio is reduced first. If the load can still be driven after the reduction, then the preset U / F ratio is too high and the excitations current peak is too large, which can reduce the current by reducing the U / F ratio. If the fixed load is reduced, then the increased capacity of the inverter should be considered, and if the inverter has the vector control function, the vector control mode should be adopted.
2. Check whether the motor is hot. If the motor temperature rise is not high, first check whether the preset of the electronic thermal protection function of the frequency converter is reasonable. If there is still space for the frequency converter, the preset value of the electronic thermal protection function should be relaxed. There is no need to relax, according to the required production process, the overload phenomenon is a normal overload, indicating that the frequency converter selection is not appropriate, the capacity of the frequency converter should be increased, replace the frequency converter. When the motor drags the variable load or the intermittent load, as long as the temperature rise does not exceed the rated value, the overload is allowed in a short time (a few minutes or a few minutes), but the frequency converter is not allowed. If the temperature rise of the motor is too high, and the overload is a normal overload, it means that the motor load is too heavy. At this time, the transmission ratio should be appropriately increased to reduce the load on the motor shaft. If possible, the transmission ratio should be increased, and if the transmission ratio cannot be increased, the capacity of the motor should be increased.
3. Check whether the operation is wrong. If the above inspection is no problem, check whether it is wrong. Check the method is in the case of light load or no load, with the ammeter measuring frequency converter output current, compare with the display display running current value, if the display shows the current reading is much larger than the actual current, the frequency converter internal current measurement part error is larger, "overload" trip may be wrong action. Blowing molding machine frequency converter overload trip reasons and treatment methods are said here, when the blowing molding machine frequency converter overload trip, according to the above steps to do will quickly and effectively solve the problem.
English
