Generator rotor repair following motorization incident

摘要

A hydrogen-cooled generator experienced a motorization incident resulting from the main breaker closing and re-opening 11 repotted times over a four-minute period. Upon retaining ring removal at the site, severe arc damage was discovered in therotor tooth top area and the retaining ring shrink fit area. The generator rotor was sent to the OEM manufacturing facility for damage assessment and possible refurbishment. Metallurgical testing and finite element analysis were utilized to quantify theremaining cyclic duty life. To satisfy future cyclic duty expectations. a modification was designed to repair arc damage in the rotor tooth top area.This paper reviews generator rotor damage and consequences typical of motorization incidents. Damage assessment techniques and repair options will also be discussed.