Vibration data was taken on a motor/pump during initial training on the Acoem Falcon. This pump was chosen based on history and a visual inspection. The visual inspection pointed towards a potential misalignment issue.
Black rubber coupling dust
Plastic shims under only the right side of the motor
Misalignment Diagnosis
The Accurex software in the Falcon diagnosed misalignment. This was confirmed by the Acoem EVO laser alignment tool.
Accurex Summary
EVO results of “As Found” Alignment
Acceptable Alignment Tolerances
This motor/pump operates at 1800 RPM. Acceptable alignment tolerances for 1800 RPM are +/- 0.7mils/1” (0.0007”/1”) for the angular tolerance and +/- 4.0 mils (0.004″) for the offset tolerance.
We suspect the original alignment was done using only a straightedge. We suspect this because the vertical & horizontal offset coupling values were fairly close to tolerance, with a vertical offset of -9.6 mils (0.0096”) and horizontal offset of -6.1 mils (0.0061”). However, the angular coupling values were way out of tolerance. This is typical for machines aligned with a straightedge. It is very difficult to “see” the angular misalignment when only using a straightedge.
Additionally, the vertical angularity of +14.3mils/1” is more than 20 times the tolerance and the horizontal angularity of -7.4mils/1” is more than 10 times the tolerance. Due to the extreme angular misalignment, the motor rear feet were 292 mils high (0.292”) in the vertical plane and out by 164 mils (0.164”) in the horizontal plane. That is over ¼” vertically and over 1/8” horizontally!
Angular Coupling values are outlined in red. Rear feet values are outlined in yellow.
Effects of Angular Misalignment
Inspection of the coupling insert clearly shows the damage caused by the extreme angular misalignment.
Pump Alignment Success: Base Modifications
The alignment could not be completed without base modifications. However, once they were completed, we were able to properly align the pump in 30 minutes.
A fresh set of vibration data was taken on the motor/pump with the Accurex software, confirming that correcting the misalignment corrected the issue.
Accurex Summary after alignment.
EVO results of “As Left” Alignment
Conclusion
- Immediate results can be obtained when starting a condition monitoring program. Tools such as the Falcon with Accurex can help novice and experienced analysts.
- Visual inspections are an important part of machinery analysis.
- Straightedge alignments are not sufficient for this type of equipment.
- Documentation of the alignment condition during startup and commissioning would have prevented this issue.
Additional Resources
- Blog Post – The Importance of Alignment and Balance
- Visual Inspection
- It’s Brand New – It Must Already Be Aligned
- Why Align – We Use Flexible Couplings
- Know Your Alignment Tolerance
- Aligned at the Factory – Realigned in the Field
- Why Can’t I Just Use My Straightedge
- Energy savings due to precision alignment
- Why misalignment draws more current
- 5 Effects of Misalignment
- How to Read an Alignment Report
