INDUSTRIAL ENERGY FACILITY (COUPLING MISALIGNMENT DIAGNOSIS)
- Customer: Industrial energy production facility
- Asset: 7 MW Turbine and gearbox assembly (GTA)
- Industry: Energy recovery / industrial turbine systems
- Initial Condition: Excessive vibration levels (>7 mm/s) detected by traditional accelerometers and displacement sensors after maintenance shutdown.
Problem Statement
Two separate vibration consultants delivered conflicting recommendations:
Consultant A:
- Machine operating at tolerance limits
- Suspected misalignment
- Recommended checking alignment between turbine and gearbox
Consultant B:
- Suggested structural tightening
- Possible balancing but no guarantee of results
The customer was not confident in these assessments and sought a contradictory diagnosis using a different methodology.
POC Objective
- Use torsional vibration analysis to identify the true root cause of excessive vibration
- Differentiate between misalignment, structural defects, and rotor-related issues
- Provide a reliable basis for maintenance decisions
Measurement Setup
- Technology: Torsional vibration diagnostics derived from speed-sensor data
- Analysis scope: Bearings, wheel behaviour, coupling dynamics, structural stiffness
Key Findings
Torsional vibration analysis revealed:
Mechanical Condition
- Radial instability in the turbine wheel
- Inlet bearing: instability due to irregular mechanical loading, though support still acceptable
- Exhaust bearing: good mechanical stability
- Thrust bearing: acceptable condition
- Turbine wheel: good condition
Coupling Condition
- Coupling operating in fatigue mode
- Caused by dynamic misalignment from uneven support forces between turbine and gearbox
- Misalignment linked to deformation during recent maintenance work
Structural Condition
- Structural stiffness asymmetry caused by civil foundation design
Consensus Achieved
After presenting findings in a joint meeting, the previous consultant (Maintenance Partner) agreed:
- The root cause of the vibration was a deformed coupling introduced during maintenance, not rotor imbalance or improper loading.
Action Taken by Customer
- Confirmation of coupling deformation
- Prioritisation of coupling correction and structural alignment
- Avoidance of unnecessary balancing operations
Benefits & Outcome
- Clear identification of the actual root cause
- Resolution of conflicting expert opinions
- Avoided misdirected maintenance
- Improved confidence in asset condition through physics-based diagnosis
Potential Savings to Customer
- Avoided repeated incorrect interventions (balancing, rechecking alignment
- Prevented premature coupling failure due to fatigue
- Reduced outage risk and maintenance cost
- Improved long-term reliability of turbine–gearbox assembly