Machine Condition Monitoring

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Machine Condition Monitoring

• Introduction

Metra Mess- und Frequenztechnik Radebeul /
Germany www.MMF.de
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Machine Vibration Monitoring
Machine Maintenance

• 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

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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

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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

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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

VM12
VM15
M12
VS6
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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

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Machine Vibration Monitoring

• Recommendations for Sensor Locations to ISO
  10816-1
• 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.

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Machine Vibration Monitoring

• The following illustrations show some examples
  for suitable measuring points

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Machine Vibration Monitoring
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Machine Vibration Monitoring

• Recommendations for measuring points at different
  types of machines can also be found in ISO
  13373-1. horizontal

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Machine Vibration Monitoring

• Vibration Severity Limits to ISO 10816-1
• If no reference values of vibration severity are
  available on the relevant machine, the
  recommendations of ISO 10816-1 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

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Machine Vibration Monitoring

• Vibration Measurement on Reciprocating Engines to
  ISO 10816-6
• 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 10816-6 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).

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Machine Vibration Monitoring

• Vibration Measurement on Reciprocating Engines
  to ISO 10816-6
• A New machines
• B Continuous running without restriction possible