SOP: THRUST BEARING & HYDRAULIC BALANCE | FRANCIS UNIT 1
SOP-MECH-012 REV 2.1

THRUST BEARING & HYDRAULIC BALANCE

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THE SILENT KILLER

AXIAL OVERLOAD RISK

While main bearings handle radial weight, the thrust bearing faces massive horizontal forces. If the runner balance holes clog, the load can triple instantly.

RUNNER
~220 kN
THRUST PAD

BALANCE HOLE SYSTEM

DESIGN INTENT

4-8 holes in the runner hub allow high-pressure water to bypass to the draft tube side, reducing axial load from 220kN to its safe 80-100kN design range.

  • Equalizes pressure behind the runner.
  • Prevents thrust pad Babbitt vaporization.

SILT MANAGEMENT

River Unit 1 carries high silt during monsoon. Blockage is a guaranteed mechanical degradation factor.

CRITICAL LIMIT > 30% Blocked