5
Why Measure Vibration?
Vibration is considered the best operating parameter to judge dynamic conditions
such as balance (overall vibration), bearing defects (enveloping) and stress applied
to components. Many machinery problems show themselves as excessive vibration.
Rotor imbalance, misalignment, mechanical looseness, structural resonance, soft
foundation, and gearmesh defects are some of the defects that can be measured by
vibration. Measuring the “overall” vibration of a machine, a rotor in relation to a
machine or the structure of a machine, and comparing the measurement to its normal
value (norm) indicates the current health of the machine.
The EXAMINER 1000 measures the vibration of a machine while it is operating.
Trending these measurements shows how a machine’s condition changes over a
period of time. Analyzing these, along with other measurements, provide insight into
the condition of the machine and which components may be wearing or failing. How
to best monitor a machine’s condition requires one to know which measurements
to take and where and how to take them. Sensors are placed at strategic Points on
the machinery to monitor the machine’s condition.
The EXAMINER 1000 processes the accelerometer’s mechanical vibration
energy into an electrical signal and displays the measurement value in numerical
form for evaluation. Commonly measured physical characteristics in Predictive
Maintenance are:
• Vibration (as explained above)
• Temperature
• Oil Analysis
Temperature
As a bearing fails, friction causes its temperature (or its lubricant’s temperature)
to rise. While trending a bearing if the temperature rises followed by a vibration
increase, then it is safe to conclude their was a loss of lubrication which induced the
mechanical failure. If vibration increased first, followed by increased temperature
readings then a mechanical defect caused the lubrication failure.
Lube Oil Analysis (Ferrography)
Monitoring oil condition warns of an increase in foreign substances, such as water,
which can degrade the lubricating properties of the oil and cause bearing failures.
It also detects the presence of metallic particles carried into the oil stream. These
metallic particles are analyzed to determine which part of the machine is wearing
and how fast. Lubrication analysis is the earliest warning of a developing problem.
Lube oil testing results can be trended with On-Time software.