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Machine Condition Monitoring Introduction Metra Mess- und Frequenztechnik Radebeul / Germany www.MMF.dewww.MMF.de.

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Presentation on theme: "Machine Condition Monitoring Introduction Metra Mess- und Frequenztechnik Radebeul / Germany www.MMF.dewww.MMF.de."— Presentation transcript:

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

2 Metra Mess- und Frequenztechnik Radebeul / Germany Machine Vibration Monitoring 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 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 Machine Maintenance

3 Metra Mess- und Frequenztechnik Radebeul / Germany 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

4 Metra Mess- und Frequenztechnik Radebeul / Germany 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

5 Metra Mess- und Frequenztechnik Radebeul / Germany Machine Vibration Monitoring Vibration Monitoring Permanent Monitoring Vibration switches Vibration severity monitors Spectrum monitors Regular Patrol Hand-Held vibration severity meters FFT analyzers Data loggers VM12VM15M12VS6

6 Metra Mess- und Frequenztechnik Radebeul / Germany 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

7 Metra Mess- und Frequenztechnik Radebeul / Germany 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.

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

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

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

11 Metra Mess- und Frequenztechnik Radebeul / Germany 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

12 Metra Mess- und Frequenztechnik Radebeul / Germany 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).

13 Metra Mess- und Frequenztechnik Radebeul / Germany 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


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