It goes to circuits basics.... in a robot axis, current flows from DC+, through servo amp IGBTs through motor cable, motor, again through motor cable, IGBTs and finally DC-. IGBTs form three phase H- bridge (two per phase, so total of 6 transistors per IGBT module). in a series circuit current is the same regardless if you measure current at the beginning, middle or end of the circuit so of course this measurement is done in the servo drive and not in the motor.. if there is a defect in a drive. It is possible that current flows straight through IGBTs and not through motor. Therefore even if motor cable is removed, current path could still exist.
IGBTs seem to be workable. I checked them with a tester. I immediately thought of them. Do you know what voltage should be applied to power the H-bridges? I have 13 V from the KPP to the bridges in the KSP. Even when I disconnect the load from the KPP (I disconnect the connector), the KPP still outputs approximately 13.1 V to the power circuit. It seems to me that this is very little to power the servo motors. It bothers me a lot.