What is the minimum pitch diameter ratio for boom hoisting sheaves compared to the nominal diameter of the rope used?

The minimum pitch diameter ratio for boom hoisting sheaves is an important specification that ensures the longevity and proper functioning of the hoisting system. The correct answer indicates a ratio of 15 times the nominal diameter of the rope used.

This ratio is essential because it minimizes bending stress on the rope as it traverses the sheave. A larger pitch diameter allows for a smoother path for the rope, reduces wear, and helps prevent premature failure of both the rope and the sheave. When the pitch diameter ratio is lower than recommended, it can lead to excessive bending, kinks, and potential rope damage, significantly affecting safety and performance.

Selecting a sheave diameter that is at least 15 times the rope diameter aligns with industry best practices and recommendations, ensuring the operational integrity of the crane's lift system.