VARIABLE FREQUENCY DRIVE AND ROTOR RESONANCE CASE STUDY

  • By Ken Keith
  • one year ago
  • 4 views
  • Shares

A newly installed motor indicated a 1980 Hz fault. The fault was not a known bearing fault frequency, not related to operating speed, and not a multiple of line frequency. The installation did not have a loose base or soft foot condition. Upon further investigation, the default switching frequency for the variable frequency drive which is associated with that motor was determined to be 2000 Hz. Tests were conducted where the switching frequency was varied and vibration was recorded. Results were conclusive, the switching frequency of the variable frequency drive was responsible for resonant amplification of the motor rotor.