Does the component (1−2s)f0 in stator currents is sufficient for detection of rotor cage faults?

This paper shows that a well-known additional component in stator phase currents with frequency (1-2s)f₀ can be insufficient for detection of the rotor cage faults. By case study of two broken bars at various relative positions it is proven that, this characteristic component in stator currents can disappear at chosen bars positions. However, in spite of this, the distribution of currents in cage bars has always nearly the same level of assymetry. Conclusion of this paper is that the component (1-2s)f₀ should be monitored permanently for the healthy cage to detect the beginning of the cage destruction process.