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The following paper has been a work in development for multiple years, and presents a lengthy and thorough overview of the background and theory of physical rotor behavior that underlies our diagnostic and troubleshooting approach and rotor balancing methods, as well a conceptual framework for determining rotor-bearing system design and stability, and a theoretical look at defining rotor resonance and behaviors observed through the system critical speed(s).

Resonance Effect, Critical and Resonance Velocities Applied to Diagnostics, Stability, and Balancing Methods of Turbine and Generator Rotors over 40 MVA

In continuation of the above theme, the following is a rough draft/compilation of a more general view leading to the balancing methods for large elastic turbine and generator rotors, presenting first the distinction between resonance as vibration/oscillation versus what is perceived as resonance on rotating large rotors.

Draft Study - The Mechanics of Elastic Continuous Rotors with Reference to Balancing of Large Turbine and Generator Rotor Shafts

Two of our other recent writings provide more specific detail on our 2N+1 balancing method, and an in-depth, conceptual description of the behavior of eccentric rotors as they pass through a critical speed, as a means of explaining why the 2N+1 balancing method is effective for rotors with distributed mass eccentricity.

Development of a New Balancing Approach for Significantly Eccentric or Bowed Rotors

Behavior of Eccentric Rotors Through the Critical Speed Range

For practical considerations during plant turbine-generator planned outages, we published and presented a paper through the MFPT 2015 conference, providing a proven outage strategy for planned work on turbine-generator rotors, to be able to guarantee a smooth restart without the need for field balancing. The paper details crucial and often-neglected procedures that must be incorporated into a planned outage scope to properly identify and address all potential sources of rotor vibration.

Proactive Shop Strategy for a Successful Turbine-Generator Rotor Outage

An additional document can be seen by clicking here , providing a thorough summary of Z-R Consulting’s technical approach for full outage support and rotor oversight.