Im working in cement plant. The plant have various section and the problem is with this Raw Mill (RM) area PLC. The AG for the RM area connected to 3 substations which is 3P1, 2P1 and QP2. All connected using PROFIBUS to the ET200M (IM 153-2)
Two times lightning strike damaged the IM cards at the 2P1 and QP. We just replaced the cards and back to normal operation. Recent incident not because of the lighning strike. The operator just start the mill (drive with big motor) and suddenly fault appeared at the QP2 and 2P1 area. Upon checking found one IM card damage at the QP2. My question is
1. Can the card damage because of induce current? No other cable connect to the IM except the PROFIBUS.
2. Now another problem come out but at the 3P1 substation. We have two draft fans. Fan #1 start normally but when we want to start Fan#2, it trips Fan#1 and also other equipments a well. Suspect it come from outside, we isolate all the inputs&outputs to the motor but the problem still persist. I suspect the IM on this rack but no fault LED lit. Is there a possiblity the IM faulty but the LED not lit?
i attach the layout for better understanding