Apparatus and method for analysing the condition of a machine having a rotating part

Abstract

An apparatus for analysing the condition of a machine having a part rotating with a speed of rotation (fROT), comprising: a first sensor (10) adapted to generate an analogue electric measurement signal (SEA) dependent on mechanical vibrations (VMD) emanating from rotation of said part; an analogue-to-digital converter (40, 44) adapted to sample said analogue electric measurement signal (SEA) at an initial sampling frequency (fs) so as to generate a digital measurement data signal (SMD, SENV) in response to said received analogue electric measurement signal (SEA); a device (420) for generating a position signal (Ep) having a sequence of position signal values (P(i)) for indicating momentary rotational positions of said rotating part; and a speed value generator (601) being adapted for recording a time sequence of said position signal values (P(i)) such that there are angular distances (delta-FIp1-p2, delta-FIp2-p3) and corresponding durations (delta-Tp1-p2; delta-Tp2-p3) between at least three consecutive position signals (P1, P2, P3) wherein the speed value generator (601) operates to establish at least two momentary speed values (VT1; VT2) based on said angular distances (delta-FIp1-p2, delta-FIp2-p3) and said corresponding durations (delta-Tp1-p2; delta-Tp2-p3), and wherein further momentary speed values for the rotational part (8) are established by interpolation between the at least two momentary speed values (VT1, VT2).

1 . (canceled) 
     
     
         2 . A condition monitoring apparatus configured to monitor a condition of a rotating equipment, the condition monitoring apparatus comprising:
 a non-transitory computer storage memory configured to store a plurality of data strings, wherein the plurality of data values are obtained based on sampling of a signal from a sensor, wherein the sensor is responsive to one or more rotations of the rotating equipment; and   one or more hardware processors configured to:
 estimate, for the plurality of data values, a respective plurality of rotation speeds; 
 modify the plurality of data values based on the plurality of rotation speeds; and 
 determine the condition of the rotating equipment based on the modified plurality of data values. 
   
     
     
         3 . The condition monitoring apparatus of  claim 2 , wherein the estimation of the plurality of the rotation speeds comprises sequentially calculating a rate of variation in speed between each pair of the plurality of data values that are temporally adjacent. 
     
     
         4 . The condition monitoring apparatus according to  claim 2 , wherein the sensor is configured to generate an electrical signal based on mechanical vibrations emanating from the one or more rotations of the rotating component. 
     
     
         5 . The condition monitoring apparatus according to  claim 2 , wherein the rotating equipment is in a wind turbine generator.