Specialized Vibration Testing On Water Purification Plant

A construction firm needed help identifying potential issues with future pump motor replacements at a water purification plant. MSI was called to conduct specialized vibration testing on the current units and to predict how a motor change and future variable frequency drive operation (VFD) would impact the system.

Problem Statement (Challenge)
- What (type of machine):Water Purification Vertical Turbine Pump
- Where (State/ Country): Massachusetts
- Why (problem/reason): A construction firm needed help identifying potential issues with future pump motor replacements at a water purification plant. MSI was called to conduct specialized vibration testing on the current units and to predict how a motor change and future variable frequency drive operation (VFD) would impact the system.
Work Performed
- Methods: Experimental Modal Analysis (EMA), Condition Monitoring, Operating Deflection Shape (ODS), Strain Gauge
Results/ Solution
- Findings: The testing predicted that future operation would not be trouble-free due to possibilities of structural natural frequencies being present in the future VFD operating range. Although the vibration levels measured on the current pump system met the HI/ANSI specification for this style pump, a motor modification would change that. ODS testing indicated that the discharge head, soleplate, and foundation were properly connected.
- Impact: The findings led MSI to recommend a finite element analysis (FEA) of the system (calibrated to the data collected in the field) including the new motor to make modifications, preventing future issues. This pre-construction analysis saved headaches down the road that would have come up due to structural natural frequency resonance. This allowed the construction firm to be proactive in the new motor implementation and avoid having to deal with a project delay penalty clause.