Load Charts and Capacity Flashcards

On a mobile crane load chart, what does the term 'gross capacity' represent?

Answer: The total rated lift before deducting the weight of rigging and load-handling devices

Gross capacity is the chart value before subtracting rigging, hook block, and other load-handling device weights.

To find the net capacity for a lift, what must be subtracted from the gross capacity?

Answer: The weight of the hook block, rigging, and any load-handling devices

Net capacity equals gross capacity minus the weight of the hook block, slings, and other load-handling devices.

Which two factors are typically used together to locate a rated capacity on a load chart?

Answer: Load radius and boom length

Most capacity values are read at the intersection of the load radius and the boom length on the chart.

As the load radius increases on a mobile crane, the rated capacity generally:

Answer: Decreases

Capacity drops as the load moves farther from the center of rotation because leverage on the crane increases.

What does a bold line or shaded area on a load chart commonly indicate?

Answer: The point where the limitation changes from structural strength to stability (tipping)

The line separates capacities limited by structural strength from those limited by stability/tipping.

Capacities based on structural strength rather than stability are most often limited by what?

Answer: The strength of the boom and crane components

Structural-strength ratings are governed by the load-bearing limits of the boom and other components.

Why should you always use the load chart for the specific machine you are operating?

Answer: Capacities vary by model, configuration, and counterweight even on similar cranes

Each crane's capacities depend on its exact model, boom, and counterweight configuration, so charts are not interchangeable.