公开(公告)号：US20180045784A1

公开(公告)日：2018-02-15

申请号：US15653054

申请日：2017-07-18

Applicant: ROLLS-ROYCE plc

Inventor： Chandana J GAJANAYAKE ,  Sivakumar NADARAJAN ,  Amit K GUPTA ,  Chao BI ,  Nay Lin Htun AUNG ,  Jiang QUAN

IPC: G01R31/34 ,  G01R23/16 ,  G01R33/09

CPC classification number: G01R31/343 ,  G01R23/16 ,  G01R33/09 ,  G01R33/1215

Abstract: There is disclosed a method for diagnosing a fault condition in an electric machine 4, the electric machine 4 comprising a rotor 10 having an axis of rotation 14 and comprising a plurality of permanent magnets M1-M8. The method comprises: rotating the rotor 10 so that each of the plurality of permanent magnets M1-M8 passes a magnetic flux density sensor 6; measuring values of magnetic flux density using the magnetic flux density sensor 6 at a plurality of positions of the rotor 10; analysing the measured values of magnetic flux density and comparing a magnitude of a peak amplitude in a time or frequency domain with a reference value; and if the peak amplitude is below the reference value, determining that the electric machine 4 has a fault condition.