Machine Condition Monitoring Using Phase Adjusted Frequency Referenced Vector Averaging

A computer-implemented method for determining machine condition, comprising:

• acquiring an analog signal from a sensor measuring a specified parameter indicative of a condition of a rotational machine, wherein the analog signal provides at least an indication of vibration of the rotational machine and includes frequency harmonic components indicative of corresponding components of the rotational machine;
• generating a first digital signal based on the analog signal, wherein the first digital signal comprises a first plurality of analysis blocks of data, wherein each analysis block of data of the first plurality of analysis blocks of data is a time based subset of acquired data used for measurement analysis;
• determining a phase compensated complex frequency spectrum for each analysis block of the first plurality of analysis blocks;
• vector averaging the phase compensated complex frequency spectra of the first plurality of analysis blocks, thereby improving signal to noise ratio (SNR) at one or more specified reference frequencies and producing averaged spectra, wherein the one or more specified reference frequencies correspond to one or more characteristic machine and fault frequencies of the rotational machine;
• identifying reference frequency components in the averaged spectra, thereby generating average reference frequency components;
• analyzing the average reference frequency components to determine a machine condition of the rotational machine, wherein the machine condition corresponds to the indication provided by the analog signal;
• and
• outputting an indication of the machine condition.

A system, comprising:

• a functional unit;
• an input, coupled to the functional unit;
• and
• a memory, coupled to the functional unit, wherein the memory stores program instructions executable by the functional unit to:
• acquire, via the input, an analog signal from a sensor measuring a specified parameter indicative of a condition of a rotational machine, wherein the analog signal provides at least an indication of vibration of the rotational machine and includes frequency harmonic components indicative of corresponding components of the rotational machine;
• generate a first digital signal based on the analog signal, wherein the first digital signal comprises a first plurality of analysis blocks of data, wherein each analysis block of data of the first plurality of analysis blocks of data is a time based subset of acquired data used for measurement analysis;
• determine a phase compensated complex frequency spectrum for each analysis block of the first plurality of analysis blocks;
• vector average the phase compensated complex frequency spectra of the first plurality of analysis blocks, thereby improving signal to noise ratio (SNR) at one or more specified reference frequencies and producing averaged spectra, wherein the one or more specified reference frequencies correspond to one or more characteristic machine and fault frequencies of the rotational machine;
• identify reference frequency components in the averaged spectra, thereby generating average reference frequency components;
• analyze the average reference frequency components to determine a machine condition of the rotational machine, wherein the machine condition corresponds to the indication provided by the analog signal;
• and
• output an indication of the machine condition.