1. Machine Condition Monitoring
Introduction
Metra Mess- und Frequenztechnik Radebeul / Germany

2. Machine Vibration Monitoring
Machine Maintenance
Traditional Maintenance:
Periodic shutdown and overhaul schedule
Production is stopped, off-line machinery is inspected for wear and wear-prone components
Bearings, fans, gear boxes and other parts are replaced, irrespective of their potential to operate for a longer time
Between these scheduled repairs unpredicted plant breakdowns cause production loss
Unscheduled repairs may be costly
Predictive Maintenance:
Monitoring techniques include vibration, acoustic noise, temperature, oil condition
Helps to predict machine failure with sufficient accuracy to enable repair before breakdown
Maintenance can be better planned
Increased plant availability
Reduced maintenance costs
Better product quality
Increased plant safety
Metra Mess- und Frequenztechnik Radebeul / Germany

3. Machine Vibration Monitoring
Advantages of Monitoring Vibration:
Vibration magnitude is proportional to the magnitude of the problem
Vibration measurement is non-invasive
Most faults show increased vibration in an early stage of the deterioration sequence
Vibration can be measured instantaneously
Vibration can indicate severity and deterioration rate of a fault
Vibration can help to find the location of the fault
Vibration can help to find the cause of the fault
Metra Mess- und Frequenztechnik Radebeul / Germany

4. Machine Vibration Monitoring
How Machine Vibration is Generated:
Operating machinery produces vibration due to its rotational or linear motion
Increasing trends towards a higher level indicate emerging problems
Typical problems arise through - misalignment of drive train components - worn or damaged bearings - load asymmetry due to debris adhesion on rotary parts like fans etc. - incorrect assembly
Vibration generally occurs with its major component perpendicular to the rotational axis of the load transmission shaft
The amount of vibration depends on - the stiffness and geometry of the machine's structure - the machine foundation - the speed of rotation of the shaft
Metra Mess- und Frequenztechnik Radebeul / Germany

5. Machine Vibration Monitoring
Permanent Monitoring
Vibration switches
Vibration severity monitors
Spectrum monitors
Regular Patrol
Hand-Held vibration severity meters
FFT analyzers
Data loggers
VS6
M12
VM12
VM15
Metra Mess- und Frequenztechnik Radebeul / Germany

6. Machine Vibration Monitoring
Vibration Severity Monitoring:
Widespread and simple method for vibration monitoring
Measurement of vibration velocity, also called vibration severity in mm/s
Vibration severity is a measure of energy of the emitted vibration
Frequency range: 10 to 1000 Hz
ISO 10816:
The standard gives recommendations for the evaluation of machine vibration by measurements on non-rotating parts
Metra Mess- und Frequenztechnik Radebeul / Germany

7. Machine Vibration Monitoring
Recommendations for Sensor Locations to ISO :
Vibration measurements on machines should be made preferably at the housing of bearings or nearby measuring points
For routine monitoring it is sufficient in many cases to measure vibration either in vertical or in horizontal direction
Rigidly mounted machines with horizontal shafts have their highest vibration levels mostly in a horizontal direction.
Flexibly mounted machines may have high vertical components of vibration, too
For inspections, vibration should be measured in all three directions (vertical, horizontal and axial) at all bearings.
Metra Mess- und Frequenztechnik Radebeul / Germany

8. Machine Vibration Monitoring
The following illustrations show some examples for suitable measuring points:
Metra Mess- und Frequenztechnik Radebeul / Germany

9. Machine Vibration Monitoring
Metra Mess- und Frequenztechnik Radebeul / Germany

10. Machine Vibration Monitoring
Recommendations for measuring points at different types of machines can also be found in ISO horizontal
Metra Mess- und Frequenztechnik Radebeul / Germany

11. Machine Vibration Monitoring
Vibration Severity Limits to ISO :
If no reference values of vibration severity are available on the relevant machine, the recommendations of ISO can be used
Permissible values of the vibration severity are given for different machine types
The basis of the assessment is the maximum value of all measured points on the machine
Metra Mess- und Frequenztechnik Radebeul / Germany

12. Machine Vibration Monitoring
Vibration Measurement on Reciprocating Engines to ISO :
Reciprocating engines, like combustion engines and compressors, are characterized by backward and forward going masses.
The vibration generated by this motion, is higher than the vibration of rotating machinery.
ISO includes recommendations for the assessment of vibrations of reciprocating machines.
The measured quantities are the RMS values of acceleration, velocity and displacement.
They are measured at the machine block in all three axes of the room. The recommended frequency range reaches from 2 Hz up to 1000 Hz.
By means of the measured values of all three vibration quantities, the reciprocating engine may be classified as belonging to a particular class of assessment.
The following table allows this classification. At first read the relevant vibration severity level for all three measured vibration quantities. The decisive class is the highest of these three determined severity classes. In the right part of the table you find the degree of machine condition in dependence on the machine class (depending on size, construction, assembly and speed of the machine).
Metra Mess- und Frequenztechnik Radebeul / Germany

13. Machine Vibration Monitoring
Vibration Measurement on Reciprocating Engines to ISO :
A New machines
B Continuous running without restriction possible
C Not suitable for continuous running, reduced operability until the next scheduled maintenance
D Too high vibration, damage to the machine cannot be excluded
Metra Mess- und Frequenztechnik Radebeul / Germany