ISO 14839-2:2004

Overview

ISO 14839-2:2004 - Mechanical vibration: Vibration of rotating machinery equipped with active magnetic bearings (AMBs) - Part 2: Evaluation of vibration - provides practical, general guidelines for measuring and evaluating vibration for rotors supported by AMBs. The standard focuses on two primary indices measured under nominal steady-state operating conditions: shaft vibratory displacement (measured at or close to AMBs) and working coil current and voltage (measured in magnetic coils or power amplifiers). It applies to industrial rotating machines with nominal power greater than 15 kW (e.g., turbo-compressors, turbo-pumps, steam turbines, turbo-generators and electric drives) and covers both rigid and flexible AMB-supported rotors.

Key topics and technical requirements

• Measurement scope
  • Shaft vibratory displacement measured by AMB-integrated displacement transducers (radial and axial).
  • Working coil current and voltage measured at coils or amplifiers (guidance provided; not yet defined as mandatory acceptance criteria).
  • Measurements are for steady-state operating conditions; transient events (passing critical speeds) are outside this part’s scope.
• Displacement definitions and evaluation
  • Vibratory displacement includes static (eccentricity) and dynamic (orbit) components and is evaluated using signals from orthogonal transducers.
  • Maximum rotor displacement Dmax is compared to the minimum radial or axial clearance Cmin to ensure clearance margin: Dmax < Cmin.
• Evaluation criteria
  • Criterion I (magnitude): Zone limits based on displacement relative to clearance:
    • Zone A/B limit: D < 0.3 Cmin
    • Zone B/C limit: D < 0.4 Cmin
    • Zone C/D limit: D < 0.5 Cmin
  • Criterion II (change): Assessment of changes in broad-band vibration magnitude vs baseline. Significant changes indicating potential fault should be regulated to less than 25% of the upper boundary of Zone B.
• Instrumentation and procedures
  • Use AMB displacement transducers; digital acquisition or oscilloscope may be required for full orbit analysis.
  • Measurements should be made under agreed thermal and load conditions across operating speed range.

Applications and users

• Practical uses:
  • Commissioning and acceptance testing of AMB-equipped rotating machinery
  • Condition monitoring and diagnostics
  • Defining operating alarm/trip limits and maintenance planning
• Typical users:
  • OEMs (compressor, turbine, generator manufacturers)
  • Test and commissioning engineers
  • Rotating machinery condition monitoring and reliability teams
  • AMB system designers and integrators
  • Standards and compliance engineers

Related standards

• ISO 14839-1: Vocabulary (part of the same series)
• ISO 10814: Evaluation of transient vibration while passing critical speeds (transient events)
• ISO 7919-1: Vibration guidelines for non-AMB (oil-film) bearings - used for reference and comparison

Keywords: ISO 14839-2, active magnetic bearings, AMB vibration evaluation, rotating machinery vibration, shaft displacement, vibration criteria, industrial rotors, condition monitoring.