The Oval Turbine Throat Ring

摘要

While performing a major overhaul on the Francis turbine-generators at a six-unit, 192-meter-head power plant, Bill, the operating engineer, dewatered Unit 2 and removed the runner. Over the 25 years the plant had been operating, Bill had carefully measured lower runner band clearance on this unit about every two years. He then rotated the runner a quarter turn to eliminate any effect from runner distortion and averaged the clearance readings.