Page 45 - Rotating Machinery Pratical Solutions to Unbalance and Misalignment

Resonance and Beat Frequencies
Chapter
Chapter
Chapter
Chapter
Chapter
Resonance and
Resonance and
Resonance and
Resonance and
Resonance and
Beat Frequencies
Beat Frequencies
Beat Frequencies
Beat Frequencies
Beat Frequencies

RESONANCE

o have a better grip on operating equipment, it is necessary
to understand resonance and beat frequencies. All ma-
T T T T T chines and machine components act like a spring-mass sys-
tem. They vibrate due to some external force acting upon them.
The vibration can either be free vibration or forced vibration. Fig-
ure 3-1 illustrates free vibration.

Figure 3-1. Free Vibration

Free vibration is simply an object vibrating at its natural or
resonant frequency. In the figure above, the mass was displaced to
the top of its motion and released. It vibrates at its natural fre-
quency. Since no additional external force is added, the amplitude
of the vibration decreases gradually with time.
One characteristic of a vibration occurring at a natural fre-
quency is that very little force is required to maintain the vibra-
tion, as compared to the force required to maintain a vibration at