张家港宏峰电器设备有限公司

1. The frequency of the inverter cannot reach the normal working frequency (40HZ). A SAMCO-i inverter, controlled by the analog quantity of the external terminal, has a frequency can only reach 20HZ, check the parameters in turn, the highest frequency and the upper frequency are both 50HZ, it can be seen that there is no problem with the parameters, immediately change to the panel given frequency, then the maximum frequency can run to 50HZ. From this point of view, the problem lies in the analog input circuit or the original device of the inverter itself, check the thermal resistance with a multimeter, the linearity is very good, there is no problem, and finally open the inverter to check and find that a chip capacitor is damaged, after replacement, the inverter returns to normal.

2. Frequent overcurrent alarm of inverter

a. Caused by incorrect parameter setting. If the acceleration time of the inverter is set too short, the change of the output frequency of the inverter far exceeds the change of the motor frequency, and when the inverter starts, it trips due to overcurrent.

This fault can be eliminated by adjusting the acceleration time accordingly depending on the load situation. 

b. If the output load is short-circuited, such as a Fuji inverter trips when it is started, check that the cable head of the contactor on the output side is rusted and loose, and the arc occurs when the machine is turned on, resulting in protection action.

c. The damage of the detection circuit will also display the transition alarm. Among them, the Hall sensor is affected by environmental factors such as temperature and humidity, and the working point drifts.

In short, among the common faults of frequency converters, large components such as IGBT power modules have few problems, and the faults caused by their peripheral circuits account for a large proportion. In daily maintenance, attention should be paid to checking the grid voltage, improving the surrounding environment of the inverter, motor and line, removing the dust inside the inverter on schedule, checking whether the terminals are tight, and minimizing the failure rate of the inverter by strengthening equipment management. At the same time, it is very important to do a good job of recording faults, and pay attention to the analysis of the load state, operation process, and fault phenomena of faults, which are conducive to future work.