TABLE OF CONTENTS No predictive maintenance program is complete until it has the three basic components: detection, analysis and correction. In the previous topics, we discussed vibration detection and analysis of machinery faults in detail. Statistics indicates that a very large percentage of machinery vibrations are due to unbalance and misalignment alone. In this section, we will discuss the correction of these common faults.
The balancing of rotors is possible in the field, but can also be done with dedicated machines. In this section, we will discuss these techniques.
Similarly, misalignment is also a major cause of unwanted vibration. Alignment correction also requires special techniques. The latest techniques that have simplified these procedures are also covered in this section.
When excessive vibrations due to resonance are encountered, it is often difficult to find an easy solution to the problem. The use of dynamic absorbers as a possible tool for controlling resonance-induced vibration will also be discussed.
It is very rare to come across a vibration spectrum of a machine that does not show a 1 component indicating some residual unbalance. Unbalance causes high levels of vibration amplitudes at the 1 rpm of the machine.
Unbalance is often defined as simply the unequal distribution of weight about a rotor's centerline. The ISO defines it as a condition that exists in a rotor when the vibratory force or motion is imparted to its bearings as a result of centrifugal forces. Correction of this unequal distribution of weight about a rotor...
