What type of scale depicts the mast moment indication when rotor RPM is above 70%?

• A. Circular scale
• B. Linear scale
• C. Digital display
• D. Gradual scale

Answer: (A)

A circular scale is specifically designed to provide visual feedback on various parameters, such as mast moment indication, in a way that allows for quick interpretation. When rotor RPM is above 70%, the circular scale effectively represents changes in the mast moment by displaying a sweeping pointer that moves around the dial. This visual format is intuitive, allowing operators to easily recognize and understand the status of the mast moment as conditions change, particularly at higher rotor speeds.

Other scales, such as linear scales, digital displays, and gradual scales, may not represent the data in a manner as straightforward as a circular scale. While these alternatives may provide readings, they can be less effective in conveying immediate changes and understanding at a glance, especially in dynamic situations that require quick decision-making. The design of the circular scale harmonizes well with the needs of operators in managing and monitoring lifting systems, particularly under the specified rotor RPM conditions.