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  • No : 21407
  • Release Date : 2018/08/22 16:27
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Cause of overcurrent (OC2) at constant speed

I have been using the FREQROL-A100 (18.5 kW) to drive a 5 kW cooling tower fan motor. Recently, OC2 occurs frequently. There seems no mechanical problem with the reduction gear and fan.

Motor insulation is good and I cleaned the inverter and cooled inside the enclosure, but the problem persists.
The power supply voltage is stable.
What else cause can there be?
Category : 


First of all, capacity reduction of the main circuit electrolytic capacitor is probable.
Usually, the electrolytic capacitor is replaced every 5 years on average, however, if the inverter is used at a high temperature and under a load close to 100%, the capacity reduces faster.
Capacity reduction of the main circuit electrolytic capacitor results in increase of the output current, leading to OC2.
Check if the output current has increased using the current monitor of the inverter or an ammeter. If it has increased, contact Mitsubishi FA Center for inspection and replacement of the inverter parts.
However, if the increase of the output current is rapid, the load may have the cause of OC2. Thus, check the load again.
Product Name
Inverter, magnet motor drive
Product Category

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