Evaluation of the Applicability of Frequency Response Analysis to Rotating Electric Machines

The applicability of frequency response analysis (FRA) to quality assurance and maintenance testing of rotating machines is being actively studied, as it has been proven to be a non-invasive and versatile test for identifying anomalies in transformers. In this work, a comprehensive analysis on the applicability of FRA testing for different types of rotating machines is given. Testing on different stator (random-, hairpin-, form-wound), rotor slot (open/closed), rotor core (cylindrical/ salient pole), and permanent magnet (PM) (surface/interior PM) designs is performed with and without the rotor. The applicability of FRA to testing is investigated for different stator and rotor design combinations. The influence of rotor position and guidelines on interpretation based on phase or sister unit comparison are also presented.