Gene Vogel
EASA Pump & Vibration Specialist

Vibration is the most effective and well-recognized parameter for assessing the mechanical condition of electric motors. Generally, lower vibration levels are equated with improved reliability. However, arbitrarily reducing the vibration level specification for acceptance of new and repaired motors will not necessarily result in improved reliability, and it will definitely increase costs. Further, reliance on vibration levels at 2x line frequency (2xlf) as an indicator of electric motor reliability is not effective.

EASA service centers should be on the lookout for "tight" vibration acceptance requirements. Be prepared to work with your customer to ensure a cost effective and realistic approach to setting motor acceptance criteria.

Topics covered include:

• "Tight" specifications
• Cost of compliance
• Unbalance (1xRPM)
• Harmonics of 1xRPM
• 2x line frequency
• Bearing fault frequencies