The past week we received a new piece of equipment from Germany which utilizes siemens controls. Typically in our company we use A.B. controls for 99% or all equipment. I am currently trying to troubleshoot an issue and having very little success.
The machinery has 3 drive motors on VFDs and all work fine. Start/Stop/pause/increase, decrease speed. However this machinery has a pump/motor (not on a VFD) which when selected on the HMI, it instantly trips the main panel disconnect. I have taken the motor leads off the contactor and still it trips the main disconnect instantly. It seems like the PLC is sensing an immediate ground fault however I can isolate line/lead cables from the contactor or the motors overload and it will still trip the main. The output card has correct voltage and seems to be working correctly. Could this be a programming issue?
The machinery has 3 drive motors on VFDs and all work fine. Start/Stop/pause/increase, decrease speed. However this machinery has a pump/motor (not on a VFD) which when selected on the HMI, it instantly trips the main panel disconnect. I have taken the motor leads off the contactor and still it trips the main disconnect instantly. It seems like the PLC is sensing an immediate ground fault however I can isolate line/lead cables from the contactor or the motors overload and it will still trip the main. The output card has correct voltage and seems to be working correctly. Could this be a programming issue?