Online Roundness Error Identification and Model-Based Monitoring for Rotors

Condition monitoring is vital for operating rotors safely. The application of model-based approaches allows a more detailed diagnosis than signal-based methods. Yet, model-based methods require identifying the properties of the undamaged rotor accurately. Measurements at single parts and modal analysis help to verify the rotor model. When monitoring rotor displacements with eddy-current sensors, also roundness errors must be considered. For roundness identification at operation speed, a method based on three non-orthogonal eddy-current sensors is presented. Several experiments show that the measurement data can be split into the contents rotor orbit and roundness error. The extracted orbit is evaluated by an academic model-based monitoring system developed for our test rig. Currently, it can evaluate unbalance, bow, misalignments and/or stator contact.