Gene Vogel
Pump & Vibration Specialist
Electrical Apparatus Service Association
St. Louis, MO
The paper "Shaft Alignment: Rock ’N’ Roll Machinery Style" by Gene Vogel, presented at the EASA Convention 2015, delves into the intricacies of shaft alignment in industrial machinery. Vogel emphasizes that while technicians often learn shaft alignment as a procedural task, a deeper understanding of the relationship between shaft centerlines and their response to alignment moves is crucial for handling unexpected situations in industrial environments.
The paper begins by discussing the fundamental concept of misalignment, explaining that shaft centerlines can be coincident, parallel, or skew. The most general case is skew centerlines that do not intersect, which becomes the defining case for alignment. Vogel explains that the severity of misalignment is determined by the angle between the spool centerline and the shaft centerlines at the flex planes. This angle is crucial for understanding alignment tolerances.
Vogel then transitions to visualizing misalignment in vertical and horizontal planes, using an XYZ coordinate system. He explains that offset and angularity in these planes are described by the intersection lines of the vertical planes containing the shaft centerlines with a horizontal plane. The paper provides a detailed example of calculating offset and angularity, illustrating how to determine the necessary correction moves.
The paper also addresses the challenges of aligning machines with base-bound or bolt-bound conditions, where both machines need to be moved to achieve proper alignment. Vogel explains how to calculate the required moves by drawing a zero line that minimizes the moves and avoids limiting bounds.
Tolerances are discussed in the context of limiting the angle between the shaft centerline and the spool centerline. Vogel explains that the objective of shaft alignment is to reduce vibratory forces to an acceptable level. He provides examples of alignment tolerances published by alignment tool vendors and industry experts.
The concept of target values is introduced, emphasizing the importance of aligning the centerlines to an offset position to account for thermal growth, torque strains, and piping strains. Vogel explains the OL2R (off-line to running) measurement process, which involves measuring the change in position from cold, off-line conditions to normal operating conditions.
The paper concludes with practical advice on moving the machine cases and addressing soft foot conditions. Vogel highlights the importance of ensuring that the machine is stable and free from soft foot conditions, which can affect alignment and machine reliability. He also emphasizes the need for proper training on alignment tools and understanding the alignment process beyond just using the tools.
Key Points Covered:
- Fundamental concept of misalignment and shaft centerlines
- Visualizing misalignment in vertical and horizontal planes
- Calculating offset and angularity for alignment corrections
- Addressing base-bound and bolt-bound conditions
- Understanding alignment tolerances and their importance
- Using target values to account for thermal growth and other strains
- Practical advice on moving machine cases and addressing soft foot conditions
Key Takeaways:
- A deeper understanding of shaft alignment is crucial for handling unexpected situations in industrial environments.
- Misalignment severity is determined by the angle between the spool centerline and the shaft centerlines at the flex planes.
- Visualizing misalignment in vertical and horizontal planes helps in understanding and correcting alignment.
- Properly addressing base-bound and bolt-bound conditions is essential for achieving alignment.
- Alignment tolerances are important for reducing vibratory forces to acceptable levels.
- Using target values helps in aligning machines to account for thermal growth and other operational strains.
- Ensuring machine stability and addressing soft foot conditions are critical for successful alignment and machine reliability.
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