Gear Assembly Phase Frequency????

[jmack]

We have had a vibration in the third section of the paper machine which has the following characteristics.
In velocity: 13650cpm - 0.067ips, 18225cpm - 0.082ips, 22725cpm - 0.0525ips, 27075cpm - 0.069ips.
In acceleration: distinct peak at 4560cpm at around 0.02 g's with a gradual decrease in amplitude for each harmonic (6 harmonics clearly visible above floor noise).

The measurements were taken from a BS felt roll bearing and similar readings have shown up on various rolls around the dryer to bottom idler gear assembly. Dryer gear has 96 teeth and rotates at approx. 190 cpm. Bottom idler gear has 84 teeth. Is it possible this is a gear assembly phasing problem?

JMacK

 

[vib1]

Determination of number of assembly phases (Na):
Determine prime factors of number of gear teeth, Ng
F1xF2xF3xF4 = Ng
Determine prime factors of number of pinion teeth, Np
F1xF2xF3xF4 = Np
Calc. product of prime factors common to gear and pinion
Na = product of common prime factors
Assembly phase passage frequency
fa = fm/Na

wher fm = mesh freq.