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Machine monitoring method

  • US 4,989,159 A
  • Filed: 02/15/1989
  • Issued: 01/29/1991
  • Est. Priority Date: 10/13/1988
  • Status: Expired due to Fees
First Claim
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1. A method of continuously monitoring the operational state of a machine, particularly a complicated machine with at least two rotating parts, working at different revolutionary rates and in mutual co-action, sensed vibration states being processed by analysis of frequency spectra while utilizing sampling and pattern recognition techniques, abnormal operational conditions being detected by calculating the probability of a sensed vibration state differing significantly from normal operational states, which are represented by a reference class calculated on the basis of previously sensed vibration states during normal operation of the machine, said method comprising the steps of:

  • (a) calculating expected peaks in a vibration spectrum theoretically for each vibration-generating machine part or partial system in the machine and the occurring revolutionary rates;

    (b) selecting a plurality of peaks in the respective vibration spectrum during continuous sensing of the actual vibration states;

    (c) matching at least one of said expected peaks to each selected actual peak, and assigning to each such match an adjustment weight, which increases with the amplitude of the actual peak and decreases with the frequency distance between the actual and its matched calculated peak;

    (d) summing all adjusting weights associated with a given machine part or partial system to form a part weight;

    (e) forming a weight vector corresponding to the machine in its entirety, the components of this vector comprising said part weights; and

    ,(f) forming said reference class on the basis of a plurality of weight vectors, each new weight vector being compared with said reference class, whereupon it is determined whether the difference exceeds a predetermined statistical spread value.

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