Question 506Steam Plants - Assistant Engineer

The correct answer is D. Axial float refers to the ability of a pinion gear to move slightly back and forth (axially) within the gear train. This allows the pinion to self-align and properly mate with a fixed double helical gear, which establishes the position of the pinion in the gear train. This design helps eliminate excessive tooth loads that can occur due to misalignment of the journal bearings. The other answer choices do not accurately define the term "axial float" in the context of reduction gears. Option A describes radial float, not axial float. Option B refers to eliminating axial thrust, not axial float. Option C is incorrect as it does not specifically address the pinion's ability to move axially.