IEC TS 60034-24 pdf download Rotating electrical machines – Part 24: Online detection and diagnosis of potential failures at the active parts of rotating electrical machines and of bearing currents – Application guide
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 1 081 6 and ISO 791 9);
– 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).
2 Normative references
There are no normative references in this technical specification.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
the factor, related to a distributed winding, which takes into account the reduction in the generated voltage due to the phase difference between the voltages generated in the coils in different slots
[IEV 41 1 -38-37]
chording (pitch) factor
the factor, related to a distributed winding, which takes into account the reduction in the generated voltage, when the winding pitch is not 1 00 %
[IEV 41 1 -38-38]
the factor, related to a distributed winding, which takes into account the reduction in the generated voltage due to the phase difference between the voltages generated in the seriesconnected branches
4 Basis of the diagnosis
The ability of electrical machines to operate is based on the existence of a magnetic field in the air-gap, which is looping in a cross-sectional area of the laminations of stator and rotor. Flux components in the end-portions of the machine outside the cores are of a parasitic nature. Therefore available signals suitable for the detection of potential faults originate from the magnetic field in the air-gap, which shall be analyzed in order to distinguish between those components which occur under regular operating conditions and those components which are attributed to a specific failure and which do not exist in a healthy machine.