Our fan 400 kW motor is being driven by ACS 880 VFD and operating since 2016. Now we face a problem with fault code 3280. We check what the manual stated, loose connection, voltage fluctuation, etc and found out all are normal. We decided to replace the whole power module including control board and memory card assuming that problems maybe electronics. After replacement we operate for more than 10 days. We concluded that it is the module, but today we experience the fault again. From your expert opinion, what could be the causes and how to resolve?