Common Fault Solution of Undervoltage in Maintenance Fault of Shandong Inverter
Frequency converter faults are often heard voltage common faults, but under-voltage common faults are often encountered in soft starter applications. The reason is that the main control circuit working voltage is less than the low limit caused by the maintenance posture or rectifier bridge on a road damage or power grid instantaneous speed blackout, typing missing the same.
According to the working voltage of the fixed comparator side of the voltage regulator, the tested working voltage is sampled and compared with it。 The results are output according to the comparator。
Detection (Analog/Digital Converter)
The detected voltage falls within the detectable range of ADC after being sampled by resistance step-down. The alarm range of voltage can be set by program.
The capacitor of energy storage technology in the main power supply circuit is harmful to the over-voltage and under-voltage of the soft starter in operation. The various parts of the soft starter power supply circuit have to be used for a period of time, so once the frequency converter components reach their service life, they will bring about faults. For example, the reason of energy storage capacitor or or other parts in the main circuit may affect the main circuit, thus causing the failure of the whole frequency converter. Usually, if the frequency converter is out of service for more than one year, a comprehensive physical examination of the energy storage capacitor should be carried out.
How to avoid this phenomenon for long time unused converters?
According to the regulations, the soft starter should be plugged in every one or two months, 20 to 30 minutes each time. For electrolytic tundishes that are not needed for a long time, when plugging in, the rated current should be increased by about 50%. If the charging time is about 30 minutes, its leakage current will drop and it can be used normally.
In addition, the capacity of storage capacitors must also be tested for the frequency converters with long service life (more than five years). Frequent undervoltage failures in operation are mostly due to insufficient capacitance of capacitors in DC circuits, capacity decline or loss of capacitance.http://www.ondjkwu.cn