SHAFT ASSEM. 2D9531 - Caterpillar

Vibration Summary
Vibrations can have many causes such as those listed in A through F:A. Unbalance of rotating or reciprocating parts.B. Combustion forces.C. Misalignment of engine and driven equipment.D. Inadequate anchoring of equipment.E. Torque reaction.F. Resonance with the mounting structure.Causes of vibrations can usually be identified by determining if:1. Vibration forces increase with speed. These are caused by centrifugal forces bending components of the drive train. These are normally caused by A, B, or C.2. Vibrations occur within a narrow speed range. This normally occurs on equipment attached to the engine-pipes, air cleaners, etc. When vibrations "peak out" in a narrow speed range, the vibrating component is in resonance. These vibrations can be modified by changing the natural frequency of the part by stiffening or softening its mounting. A defective viscous vibration dampener can also cause this.These are normally caused by A, C, or F.3. Vibrations increase as load is applied. This is torque reaction and can be caused by insecure mounting of engine or driven equipment, or by a base or foundation which is not sufficiently rigid to withstand the driving torque of the engine or defective worn couplings. These are normally caused by D or E.Order of Vibration
Order of Firing Frequency
Data Interpretation
First Order Vibration Frequencies for Standard Rated Speeds
Relationships of Sinusoidal Velocity, Acceleration, Displacement