Electromagnetic Forces and Mechanical Stresses in the Outer Segments of Turbine Generator Stator
M. Roytgarts Department of Turbo Generators, JSC Power Machines, Saint Petersburg, Russia 2026-06-27

Abstract

In light of design features, electromagnetic loads and operating modes of turbine generators, a traveling wave of
electromagnetic force density acting on the outer segments of the stator end stacks was determined. Concentration of force action on the edges of the teeth of loose segments is introduced in the analytical solutions for the ripple bending electromagnetic moments acting on the radial and tangential fixings (restraints) of the segments. Solutions for bending moments are obtained using the equivalent concentrated force in terms of generalized functions. It has been established that, for the ratios of the width of the teeth and the pole arcs used in turbine generators, bending moments are substantially unchanged across the width of the teeth, regardless of the location of the restraints. Stresses in the segment restraints were determined and failure criteria (if exceeded) were defined. It has been shown that the most dangerous bending stresses are those at the edges of tangential restraints, as it appears from inspections of turbine generators at power plants. Recommendations are given for preventing failure of outer segments in the end areas of turbine generators.

Key words: Turbine generator, end stacks, electromagnetic forces, mechanical stresses.

References

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