FIELD

This invention relates to the field of machine vibration data analysis. More particularly, this invention relates to a system for optimizing the collection of machine vibration data to enhance spectral waveform analysis.

BACKGROUND

In acquiring machine vibration data for spectral analysis, it is necessary to collect the data over a sufficient frequency range and with sufficient resolution to adequately distinguish between various spectral amplitude peaks, thereby enabling the identification of peaks associated with potential machinery faults. This requires defining the correct maximum frequency (Fmax) and the correct number of lines of resolution (Nlines) in configuring the vibration monitoring device that collects the data, such as the Emerson model AMS 2140 Machinery Health Analyzer.

What is needed, therefore, is a process for determining an Fmaxvalue and an Nlinesvalue to be used in configuring a vibration data collection device to acquire machine vibration data that will be sufficient for use in identifying spectral amplitude peaks associated with machine fault frequencies.

SUMMARY

The above and other needs are met by a process that determines, based on bearing fault frequencies, the optimum values for the maximum frequency (Fmax) and the number of lines of resolution (Nlines) to be used in collecting machine vibration data so as to adequately distinguish between spectral peaks for identifying faults in machine bearings. The process can be extended to any other types of fault frequencies that a machine may exhibit, such as motor fault frequencies, pump/fan fault frequencies, and gear mesh fault frequencies. Embodiments of the process also ensure that the time needed to acquire the waveform is optimized. This is particularly useful when collecting data using portable vibration monitoring devices.

Preferred embodiments provide a method implemented by a computer processor for configuring a vibration data collection device to acquire machine vibration data for use in generating a vibration spectrum. The vibration spectrum has amplitude peaks at a plurality of fault frequencies that are indicative of faults in the machine. In one embodiment, the method includes the following steps:(a) determining a maximum frequency of data collection;(b) determining a minimum frequency spacing within the plurality of fault frequencies;(c) based on the maximum frequency and the minimum frequency spacing, determining a number of lines of resolution that will allow identification of all of the amplitude peaks associated with each of the plurality of fault frequencies that are resolvable given limitations of the vibration data collection device; and(d) configuring the vibration data collection device using the maximum frequency and the number of lines of resolution.

In some embodiments, step (a) of the method includes specifying a number N of harmonics of the turning speed and a number M of harmonics of the plurality of fault frequencies to be included in the vibration spectrum, and determining the maximum frequency based at least in part on the number N.

In some embodiments, the method includes, prior to steps (a) and (b):calculating N number of turning speed frequencies associated with the N number of harmonics of the turning speed; andcalculating M number of fault frequencies associated with the M number of harmonics of the plurality of fault frequencies.
In these embodiments, step (a) includes determining the maximum frequency based at least in part on a highest frequency of the N number of turning speed frequencies and the M number of fault frequencies, and step (b) includes determining the minimum frequency spacing within the N number of turning speed frequencies and the M number of fault frequencies.

In some embodiments, step (a) of the method includes:(a1) accessing from a memory device a list of discrete maximum frequency values at which the vibration data collection device is operable;(a2) comparing one or more of the discrete maximum frequency values to the highest frequency of the N number of turning speed frequencies and the M number of fault frequencies;(a3) based on the comparing of step (a2), determining a largest one of the discrete maximum frequency values that is less than or equal to the highest frequency of the N number of turning speed frequencies and the M number of fault frequencies; and(a4) setting the maximum frequency to be equal to the largest one of the discrete maximum frequency values determined in step (a3).

In some embodiments, step (a) of the method also includes:(a5) accessing a memory device to determine a device maximum frequency value at which the vibration data collection device is operable;(a6) comparing the device maximum frequency value to the maximum frequency set in step (a4); and(a7) if the maximum frequency set in step (a4) is greater than the device maximum frequency value, setting the maximum frequency to be equal to the device maximum frequency value.

In some embodiments, if the maximum frequency is set to be equal to the device maximum frequency value, the method includes:determining a number of amplitude peaks associated with unresolved fault frequencies based on the maximum frequency and the number of lines of resolution; andgenerating a listing of the amplitude peaks associated with unresolved fault frequencies.

In some embodiments, step (c) of the method includes calculating

Nlines=2×FmaxΔ⁢⁢f,
where Nlinesis a calculated number of lines of resolution, Fmaxis the maximum frequency, and Δf is the minimum frequency spacing.

In some embodiments, step (c) of the method includes:(c1) accessing from a memory device a list of discrete number of lines of resolution values at which the vibration data collection device is operable;(c2) comparing one or more of the discrete number of lines of resolution values to the calculated number of lines of resolution;(c3) based on the comparing of step (c2), determining a largest one of the discrete number of lines of resolution values that is less than or equal to the calculated number of lines of resolution; and(c4) setting the number of lines of resolution to be equal to the largest one of the discrete number of lines of resolution values determined in step (c3).

In some embodiments, step (c) of the method includes:(c5) accessing a memory device to determine a device maximum number of lines of resolution value at which the vibration data collection device is operable;(c6) comparing the device maximum number of lines of resolution value to the number of lines of resolution set in step (c4); and(c7) if the number of lines of resolution set in step (c4) is greater than the device maximum number of lines of resolution value, setting the number of lines of resolution to be equal to the device maximum number of lines of resolution value.

In some embodiments, if the number of lines of resolution is set to be equal to the device maximum number of lines of resolution value, the method includes:determining a number of amplitude peaks associated with unresolved fault frequencies based on the maximum frequency and the number of lines of resolution; andgenerating a listing of the amplitude peaks associated with unresolved fault frequencies.

In some embodiments, the method includes determining a minimum waveform data acquisition time, which is a smallest amount of time during which the vibration data collection device can acquire vibration data without increasing a number of amplitude peaks associated with unresolved fault frequencies.

In some embodiments, the minimum waveform data acquisition time is calculated according to

Tacq=NlinesFmax,
where, Tacqis the minimum waveform data acquisition time, Nlinesis the number of lines of resolution, and Fmaxis the maximum frequency.

In some embodiments, the minimum waveform data acquisition time is determined by:(e) determining a value Mlinesaccording to

Mlines=Nlines2,

where Nlinesis the number of lines of resolution;(f) based on the value Mlinesand the maximum frequency, determining a temporary value Ntmpfor the number of amplitude peaks associated with unresolved fault frequencies Nunres;(g) if Ntmpis greater than Nunres, thensetting Nimes equal to 2×Mlines, anddetermining the minimum waveform data acquisition time Tacqaccording to

Tacq=NlinesFmax,
and

if Ntmpis not greater than Nunres, thensetting Nlinesequal to

Nlines2,
andrepeating steps (f) and (g) until Ntmpis greater than Nlines; and(h) configuring the data collection device using the minimum waveform data acquisition time.

In some embodiments, the method includes:calculating N number of turning speed frequencies associated with the N number of harmonics of the turning speed;and calculating M number of fault frequencies associated with the M number of harmonics of the plurality of fault frequencies; andgenerating a graphic display of the N number of turning speed frequencies and the M number of fault frequencies.

In some embodiments, the method is performed by a computer processor that is a component of the data collection device.

In another aspect, the invention provides a method implemented by a computer processor for configuring a vibration data collection device to acquire machine vibration data from a machine for use in generating a vibration spectrum. A preferred embodiment of the method includes the following steps:(a) determining a maximum frequency of data collection;(b) determining a minimum frequency spacing within a plurality of fault frequencies;(c) based on the maximum frequency and the minimum frequency spacing, determining a number of lines of resolution of data collection according to

Nlines=2×FmaxΔ⁢⁢f,

where Nlinesis a calculated number of lines of resolution, Fmaxis the maximum frequency, and Δf is the minimum frequency spacing;(d) configuring the vibration data collection device using the maximum frequency and the number of lines of resolution;(e) determining a minimum waveform data acquisition time Tacqaccording to

Tacq=NlinesFmax;
and(f) configuring the vibration data collection device using the maximum frequency, the number of lines of resolution, and the minimum waveform data acquisition time.

