Forces on the End Winding of Turbine-Generators II - Determination of Forces

Electromagnetic forces on the end coils of turbine-generators, following a 3-phase short circuit from no load, are determined for different positions of the rotor, ωts, in the first cycle. Forces are given by F = Il ×B. Cylindrical coordinates are used. Flux density on the field points on the coils will result from stator alternating and direct currents, rotor transient currents, and, indirectly, all currents which are induced in a nonmagnetic retaining ring. Flux densities interact with total current in each coil to give forces. The total torque on the end winding is calculated at different ωts, and its maximum is determined. Radial forces acting on both layers are analyzed. Hence, the most severe load on the supports is determined. The normal forces on the coils are calculated.