Session Start Date

5-6-1984

Abstract

A two-pole turbogenerator posed problem of resonance and excessive vibrations at the operating speed during test runs in the Test-bed. The entire system comprising the foundation, pedestals supporting the generator, journal bearing seats, bearing oil-film, and the rotor has been modeled and analysed for computing the rotor's critical speeds as also the foundation's natural frequencies. Some of the system's parameters have been derived from actual tests. Sensitivity analysis for the rotor's critical speed that coincided with the operating speed of machine showed that this critical speed is relatively insensitive to the foundation mass as well as stiffness, and largely depends upon the stiffness characteristics of the journal bearings. The remedy to avoid excessive vibrations at operating speed has been thus found to lie in improving the journal bearings and their seatings.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

First Conference

Publisher

University of Missouri--Rolla

Publication Date

5-6-1984

Document Version

Final Version

Rights

© 1984 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 6th, 12:00 AM

Foundation-Bearing-Rotor Interaction Problem in Controlling Vibrations in a 120 Mw Turbo Generator

A two-pole turbogenerator posed problem of resonance and excessive vibrations at the operating speed during test runs in the Test-bed. The entire system comprising the foundation, pedestals supporting the generator, journal bearing seats, bearing oil-film, and the rotor has been modeled and analysed for computing the rotor's critical speeds as also the foundation's natural frequencies. Some of the system's parameters have been derived from actual tests. Sensitivity analysis for the rotor's critical speed that coincided with the operating speed of machine showed that this critical speed is relatively insensitive to the foundation mass as well as stiffness, and largely depends upon the stiffness characteristics of the journal bearings. The remedy to avoid excessive vibrations at operating speed has been thus found to lie in improving the journal bearings and their seatings.