Machine fault detection using vibration signal peak detector

A fault detection apparatus for receiving machine vibration and speed signals, processing said vibration signal to produce a processed vibration signal, and synchronously averaging the processed vibration signals at the speed indicated by the speed signal to determine the presence of a fault in a rotating element of the machine where the rotating element is rotating at the speed indicated by the speed signal, the apparatus comprising:

• a peak value detector for receiving the machine vibration signal, sampling said vibration signal during predetermined sample time periods, and detecting the peak amplitude values of the vibration signal during the sample time periods, producing a time series of peak amplitude values;
• clock means for generating at least one clock signal, said peak value detector being responsive to said at least one clock signal to set the length of said sample time periods;
• and
• means for synchronously averaging said time series of peak amplitude values at the speed of said rotating element, producing a time series of synchronously averaged amplitude values.

A fault detection system for detecting mechanical faults of machines having one or more rotating elements that generate mechanical vibrations while rotating, including an accessible element and a target element, the system comprising:

• a vibration sensor for sensing vibrations generated by at least a target rotating machine element during machine operation, producing a vibration signal containing a plurality of amplitudes and frequencies;
• a peak value detector for sampling said vibration signal during predetermined sample time periods and detecting the peak amplitude value of the vibration signal during the sample time periods, producing a time series of peak amplitude values;
• clock means for generating at least one clock signal, said peak value detector being responsive to said at least one clock signal to set the length of said sample time periods;
• a speed sensor for sensing the speed of an accessible rotating machine element, producing a speed signal;
• a pseudo-speed circuit for adjusting the speed signal to reduce errors and to compensate for a rotation ratio between the accessible rotating machine element and the target rotating machine element, producing a pseudo-speed signal;
• and
• means for reading said time series of peak amplitude values, receiving said pseudo-speed signal, and synchronously averaging said time series of peak amplitude values at the speed indicated by said pseudo-speed signal, producing a time series of synchronously averaged amplitude values corresponding to possible sources of the mechanical vibration.

A method of processing, for further analysis, a vibration signal generated by a vibration sensor attached to a machine, the method comprising the steps of:

• determining the peak amplitude value of the vibration signal with a peak value detector during sample time periods, producing a time series of peak vibration amplitudes;
• transforming said time series of peak vibration amplitudes to the frequency domain to produce peak vibration spectra;
• and
• outputting the peak vibration spectra for further processing.

A method of detecting faults in a machine having rotating machine elements, said elements including at least an accessible element and a target element, said method comprising the steps of:

• producing a vibration signal containing amplitudes and frequencies, said vibration signal being representative of vibrations generated by at least the target rotating machine element;
• sampling said vibration signal during predetermined sample periods of time;
• determining the peak amplitude value of said vibration signal during each sample period of time to produce a time series of peak amplitude values;
• producing a speed signal with a speed sensor, said speed signal being representative of the speed of the target element as sensed by said speed sensor;
• synchronously averaging said time series of peak amplitude values at the speed indicated by said speed signal, producing a time series of synchronously averaged amplitude values;
• and
• transforming the time series of synchronously averaged amplitude values to the frequency domain to determine the presence of a fault in the target element.