TABLE OF CONTENTS Every rotating machine exhibits a characteristic vibration signature that is uniquely its own. The signal is the sum total of the design, manufacture, application, and wear of each of its components. If the maintenance mechanic or engineer responsible for a piece of machinery takes the time to become acquainted with the nature of the vibration of his machinery, it will not be long before he can effect substantial cost savings for his company.
This chapter originally was written to provide a "no math" way to train servicemen for a leading rotating machine manufacturer. It should go a long way toward teaching the maintenance mechanic how to identify which component of a machine, if any, is about to cause a problem and to estimate the present severity of the problem without opening the machine for inspection. This ability is valuable because it allows for the following:
Reduction of unscheduled down time
Reduction of turnaround time
Elimination of periodic disassembly of a machine for the purpose of inspection
Greatly reduced probability of a machine "crash"
Vibration is defined as a small oscillation about some equilibrium point. To describe vibration, one must speak of the amplitude, frequency, and phase of a series of wave forms called sine waves.
Suppose we have a piston driven by a crankshaft moving up and down in a cylinder as in Figure 1.1. The crankshaft is rotating at a speed of one revolution per second (1 Hz). One way to describe the motion of...
