How to calculate vibration frequency from vibration velocity?
Answers
Answer:
Explanation:
Vibration is the back and forth or repetitive motion of an object from its point of rest.
When a force is applied to the mass, it stretches the spring and moves the weight to
the lower limit. When the force is removed, the stored energy in the spring causes the
weight to move upward through the position of rest to its upper limit. Here, the mass
stops and reverses direction traveling back through the position of rest to the lower
limit. In a friction-free system the mass would continue this motion indefinitely. All
real systems are damped, that is they will gradually come to their rest position after
several cycles of motion, unless acted upon by an external force. The characteristics
of this vibratory motion are period, frequency, displacement, velocity, acceleration,
amplitude and phase. Continued vibration of this spring mass system would only
repeat the characteristics shown in this single cycle.
All rotating machines produce vibrations that are a function of the machine dynamics,
such as the alignment and balance of the rotating parts. Measuring the amplitude of
vibration at certain frequencies can provide valuable information about the accuracy
of shaft alignment and balance, the condition of bearings or gears, and the effect on
the machine due to resonance from the housings, piping and other structures.
Vibration measurement is an effective, non-intrusive method to monitor machine
condition during start-ups, shutdowns and normal operation. Vibration analysis is
used primarily on rotating equipment such as steam and gas turbines, pumps, motors,
compressors, paper machines, rolling mills, machine tools and gearboxes. Vibration
analysis is used to determine the operating and mechanical condition of equipment. A
major advantage is that vibration analysis can identify developing problems before
they become too serious and cause unscheduled downtime. This can be achieved by
conducting regular monitoring of machine vibrations either on continuous basis or at
scheduled intervals. Regular vibration monitoring can detect deteriorating or defective
bearings, mechanical looseness and worn or broken gears. Vibration analysis can also
detect misalignment and unbalance before these conditions result in bearing or shaft
deterioration. Trending vibration levels can identify poor maintenance practices, such
as improper bearing installation and replacement, inaccurate shaft alignment or
imprecise rotor balancing.