This part of IEC 60034 is applicable to the on-line detection and diagnosis of failures at the active parts of multi-phase rotating electrical machines (induction and synchronous machines) and of bearing currents. The failure analysis includes: – interturn faults; – phase-to-phase short-circuits; – double earth faults and single earth faults of motors with earth connection of the starpoint; – static and dynamic eccentricities; – cage imperfection or defects (e.g. broken bars or end-rings); – bearing currents. This can be achieved by tools like search coils or other magnetic sensors or partly by the analysis of the terminal voltages and currents. The detection of the following effects is excluded from the scope: – vibration (covered by ISO standards, e.g. ISO 10816 and ISO 7919); – partial discharge (covered by IEC 60034-27); – single earth-faults of motors without earth connection of the star-point; – core imperfection. Also excluded are special methods applicable for specific applications only (e.g. turbo generators).