Industrial Fan Vibration Analysis

Industrial fan vibration analysis is simple to understand once it is explained. Depending upon the type of process, fluid and desired flow rates, these fans are designed accordingly. These fans are mounted on a shaft which is driven by high power motor. The shaft is a rod which connects the motor with the fan (rotor element). Balancing of the fan is of utmost priority while the fan is operating.

Fan Application Categories:

  • Residential
  • HVAC & Agricultural
  • Industrial Process
  • Power Generation
  • Transportation
  • Marine
  • Transit
  • Tunnel
  • Petrochemical process
  • Computer Chip Manufacturing

Lack of balancing leads to vibration and excessive unbalancing might lead to malfunctioning of equipment. The term balancing refers to additions or removal of mass from the fan shaft in order to fix the center of gravity to its axis of rotation. The vibrations might be affected by wheel balance, drive components, number of revolutions, wiring and motor operation. There are different fan application categories as shown in chart above.

Industrial Fan Vibration Analysis as a Cost Effective Technique

Vibration analysis is a cost effective technique to ensure smooth running of a fan. It’s a diagnostic tool to check out the vibrations occurring in the fan. Velocity and amplitude testing are most commonly carried out in vibration analysis. Velocity measurement gives the severity of vibrations and amplitude implicates the maximum deviation from the mean position.

Vibrational Limits for Tests Conducts in the Factory
Fan Application Category Rigidly Mounted in./s Flexibility Mounted in./s
BV-1 0.50 0.60
BV-2 0.20 0.30
BV-3 0.15 0.20
BV-3 0.10 0.15
BV-5 0.08 0.10


In vibration test analysis technique, the fan to be analyzed is mounted on a flexible or rigid base. In the case of a rigid system there must be more natural frequency than running speed. One example of a rigid base is the fixing of a fan on concrete foundations. For flexible systems the natural frequencies must be less than running speed. An accelerometer measures the amplitude in horizontal and vertical directions. Once the unit is mounted and prepared for the vibration testing, it is allowed to run at desired speed. It is ensured in the testing that the vibrations of fan fall in allowable vibration ranges.

There are many more detailed observations and tests that can be performed in the field of industrial fan vibration analysis as are differing patterns of results, charts, graphs and reading as this is just one check work.