Machines with rotating parts vibrate, and measuring why and how much those parts vibrate can tell you a lot about the health of a machine. Consider
the rumble of worn bearings or the shaking, shimmying or
thumping of loose, misaligned or unbalanced parts. That can be
the machine talking to you. Are you willing and able to listen?
The art and science of measuring and interpreting those
rumbles and shakes — vibration analysis — has been historically the domain of specialists but recent developments in
vibration sensors, data acquisition and analysis technologies,
are now making vibration analysis cheaper, easier and more
Another innovation, laser shaft alignment tools, go hand-in-hand with vibration testing to provide a technological one-two punch against motor problems. These precision instruments make old straight edge and dial indicators a vestige of
another era. If vibration analysis reveals shaft misalignment
issues, a laser shaft alignment tool allows you to complete
fast, accurate corrections to a variety of problems impacting
alignment in a straightforward maintenance service visit.
Vibration analysis is accomplished by securely attaching
a sensor (typically an accelerometer) to the bearings of the
machine and measuring the vibration frequencies that transmit from the rotating shaft through the bearings into the outside metal surface of the machine and then into the sensor.
Among the most important mechanical faults that vibration
analysis can reveal are the following:
1. Imbalance — A “heavy spot” in a rotating component
causes vibration when the unbalanced weight rotates
around the machine’s axis, creating a centrifugal force
which will cause advanced wear in bearings and seals and
2. Misalignment — high forces can result when machine
shafts are out of line. Misalignment forces on the shafts
(for example) a motor and pump will cause advanced wear
to the bearings and seals and wasted energy.
3. Wear — As components such as bearings, drive belts or
gears become worn, they may cause vibration. When a
roller bearing race becomes pitted, for instance, the bearing
rollers will cause a vibration each time they travel over the
4. Looseness — Vibration that might otherwise go unnoticed
may become obvious and destructive if the component that
is vibrating has loose bearings or is loosely attached to its
Vibration Tools To The Rescue
For the past 30 years, there have only been two tools for
vibration analysis — the high-end analyzer and the vibration
pen (or maybe the screwdriver to the ear). Recently, two new
categories of vibration test tools have gained popularity: the
vibration tester and the vibration meter.
By John Bernet
Vibration Testing, Laser
Alignment Provide 1-2
Punch For Ailing Motors
A maintenance technician using Fluke's 805
Vibration and 830 Laser
Shaft Alignment tools.