Wyoming Public Utility Shaft Breakage Torque Study

1. Wyoming Public Utility Shaft Breakage Torque Study Problem: Shaft Breakage – (2) 1500 HP Reliance ElectricMotors Application: Driving Reciprocating Compressor for Atomizer Project Actions • Completed Motor Design review with RSN Motor Engineering 5/1 • Completed Detailed Process Review with Grand Eagle 5/8 – (Fact Finding) • Completed Initial Process Assessment 5/21 – (Research) • Installed Telemetric Strain Gage on Rebuilt Motor – (Measurement) • Compiled Motor Torque Curves – (Analysis of Findings) • Concluded Compressor was Introducing Torsion Resonance – 6/3 • Compressor Manufacturer Agreed to Install Fly Wheel – 6/12 • Customer is Presently Running Compressors at 1170 RPM’s just below 1180 RPM threshold for resonance (1192 Full RPM).

2. Public Utility Shaft Breakage Analysis Shaft Breakage Extends at 45 Degrees Indicative of a twisting moment as opposed to shear Sleeve Bearing Wear Pattern Indicative of a extreme radial forces

3. Torque Analysis Using Telemetric Strain Gage Chart #1: Shaft displacement at full load and 1192 RPM run speed. Four Modes of displacement are present. (Full Spectrum) Chart #2: Shaft displacement filtered to 4 times to demonstrate displacement frequency was directly proportional to four stage compressor action. Chart #3: Shaft displacement filtered to 1 times to demonstrate shaft displacement frequency was directly proportional to any one stage in four stage compressor. Chart #1: Chart #2: • Conclusions: • - Torsional Resonance • Corrective Actions: • Operate below critical speed until • flywheel is installed • Result: • - Resolved Customer Application Issue • Mitigated Warranty Exposure Grand • Eagle / Baldor • - Torsional resonance issues resolved after installation of flywheel to critically damp system Chart #3:

4. Coast-to-CoastCoverage