TANK & MTG GP-HYDRAULIC & FUEL 1302050 - Caterpillar

Table 11
Displacement    
Location of the Probe
    Overall Displmt     Order     Displacement    
1/2 1     2     3     4    
Frequency                    
1                                
2                                
3                                
4                                
5                                
Table 12
Displacement    
Location of the Probe
    Overall Displmt     Order     Displacement    
1/2 1     2     3     4    
Frequency                    
1                                
2                                
3                                
4                                
5                                Allowable Vibration Levels
Illustration 10 g01300488
Beat Frequencies
Complaints caused by beat frequencies can be hard to detect. The beat frequency will not appear in the spectrum plot. Beats are caused by two frequencies very close together that are close in amplitude. Refer to Illustration 12. Beats can be easily seen in the time scope. Illustration 11 is caused by the excitation of the engine first order and the air compressor at 1.14 order. The observed frequency is much lower than what the actual spectrum will show. Time wave for monitoring can be a valuable tool in vibration analysis.
Illustration 11 g01306883
Illustration 12 g01307974
Virtual Print
Illustration 13 g01301746
(1) Data for route point (2) Engine speed (3) Overall reading at selected point (4) Standard orders (5) Frequency units (6) Non-standard orders