Jim Bryan (deceased)
Technical Support Specialist
Electrical Apparatus Service Association
St. Louis, MO

In his presentation at the EASA 2011 Convention, Jim Bryan provides a comprehensive overview of motor lubrication, focusing on the types of bearings, lubrication methods, and best practices to ensure optimal motor performance and longevity. Bryan begins by categorizing bearings into two main types: rolling element bearings and hydrodynamic bearings. Rolling element bearings, which include ball and roller bearings, are characterized by rolling elements that separate the stationary part from the rotating part. Hydrodynamic bearings, such as sleeve and plate bearings, rely on an oil wedge to separate the stationary and rotating parts.

Bryan highlights the advantages and disadvantages of each bearing type. Rolling element bearings are less expensive, easier to assemble, and can handle both axial and radial loads. However, they require more frequent lubrication and are less tolerant of misalignment. Hydrodynamic bearings, on the other hand, offer greater reliability and can be inspected and replaced without removing the motor. They also provide better damping characteristics and can operate at higher speeds, but they are more expensive and require precise maintenance.

The paper delves into the specifics of grease and oil lubrication. Grease lubrication is preferred for its ease of maintenance and ability to prevent contamination, making it suitable for industries like food, textile, and chemicals. Oil lubrication, while more complex, allows for complete replenishment and better cooling of highly-loaded bearings. Bryan provides detailed guidelines for grease lubrication, including recommended quantities and intervals based on bearing size and motor speed. He emphasizes the importance of not over-greasing, as this can lead to elevated temperatures and potential failures.

Bryan also addresses the compatibility of different greases, noting that mixing incompatible greases can result in rapid lubricant failure. He provides a compatibility chart and recommends flushing old grease or consulting manufacturers to ensure compatibility. The paper includes practical tips for maintaining proper lubrication, such as turning the shaft periodically during storage and using space heaters to prevent condensation.

For oil lubrication, Bryan explains the importance of maintaining the correct oil level and selecting the appropriate viscosity based on operating conditions. He discusses the challenges of maintaining oil levels in vertical motors and the need for regular oil changes to prevent contamination and degradation. Bryan also highlights the importance of monitoring bearing temperatures and setting appropriate alarm and shutdown limits to prevent damage.

In summary, Jim Bryan's paper offers valuable insights into motor lubrication practices, emphasizing the importance of proper lubrication to prevent bearing failures and ensure motor reliability. His detailed guidelines and practical tips provide a comprehensive resource for service centers and maintenance professionals.

Key Points Covered:

• Types of bearings: rolling element and hydrodynamic
• Advantages and disadvantages of each bearing type
• Grease and oil lubrication methods
• Guidelines for grease lubrication quantities and intervals
• Importance of grease compatibility
• Tips for maintaining proper lubrication
• Oil lubrication practices and challenges
• Monitoring bearing temperatures and setting limits

Key Takeaways:

• Proper lubrication is essential for preventing bearing failures
• Different bearing types have specific advantages and maintenance requirements
• Grease lubrication is easier to maintain but requires careful quantity control
• Oil lubrication allows for complete replenishment and better cooling
• Ensuring grease compatibility is crucial to prevent lubricant failure
• Regular maintenance and monitoring are key to motor reliability
• Maintaining correct oil levels and viscosity is critical for optimal performance
• Monitoring and managing bearing temperatures can prevent damage and extend motor life