MASS Load Charts and Capacity 2 — Questions and Answers
Question 1: On a mobile crane load chart, what does the term 'gross capacity' represent?
- The total rated lift before deducting the weight of rigging and load-handling devices (Correct answer)
- The weight of the crane itself
- The net weight available for the customer's load only
- The maximum counterweight allowed
Correct 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.
Question 2: To find the net capacity for a lift, what must be subtracted from the gross capacity?
- The weight of the hook block, rigging, and any load-handling devices (Correct answer)
- The boom weight
- The outrigger pad weight
- The fuel weight
Correct 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.
Question 3: Which two factors are typically used together to locate a rated capacity on a load chart?
- Load radius and boom length (Correct answer)
- Engine RPM and oil pressure
- Wind speed and temperature
- Tire pressure and axle weight
Correct 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.
Question 4: As the load radius increases on a mobile crane, the rated capacity generally:
- Decreases (Correct answer)
- Increases
- Stays the same
- Doubles
Correct answer: Decreases
Capacity drops as the load moves farther from the center of rotation because leverage on the crane increases.
Question 5: What does a bold line or shaded area on a load chart commonly indicate?
- The point where the limitation changes from structural strength to stability (tipping) (Correct answer)
- The maximum travel speed
- The recommended idle setting
- The location of the cab heater
Correct 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.
Question 6: Capacities based on structural strength rather than stability are most often limited by what?
- The strength of the boom and crane components (Correct answer)
- The amount of counterweight only
- The wind direction
- The operator's reach
Correct 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.
Question 7: Why should you always use the load chart for the specific machine you are operating?
- Capacities vary by model, configuration, and counterweight even on similar cranes (Correct answer)
- All cranes share one universal chart
- Charts are only legal suggestions
- The chart only applies to new cranes
Correct 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.
MASS Load Charts and Capacity 2
On a mobile crane load chart, what does the term 'gross capacity' represent?