The ability to identify mechanical faults will be directly related to the amount and accuracy of collected drive train data.  Vendor software varies in the amount of drive train information which can be included in the database.  They also vary in the capability of automated fault frequency identification.  It is highly recommended that you conduct a “drive train map” that will include all applicable information such as:

• Coupling type
• Pulley or sheave diameters
• Number of belts and belt lengths
• Sheave pitch diameters
• Number of fan or impeller blades
• Gear box ratio's
• Bearing type
• Number of rolling elements
• Contact angles

If all of the information is not available, an effective alternative is to map the RPM at each stage of the drive train.  Perform the mapping when the motor is at normal load, using a strobe tachometer, then set up alarm band frequency parameters based on load variance.  When performing an analysis, you can then refer to the annotated parameters and determine what drive component is the likely cause of the suspect frequency.

Most mechanical anomalies will cause an increase in the run speed spectral peak.