Which system measures and indicates bending moments on the rotor mast?

• A. Mast Moment Indicator
• B. Torque Meter
• C. VEMD
• D. Rotor Tachometer

Answer: (A)

Bending moments on the rotor mast are all about how the mast flexes under wind and rotor forces. The Mast Moment Indicator is the system designed to measure and show these moments, usually by using strain sensors on the mast to detect bending and then converting that data into moment values that are displayed for operators. This helps assess structural loading and fatigue risk so maintenance and safety decisions can be made.

Other options focus on different measurements: a torque meter tracks torque along the shaft, not how the mast bends; a rotor tachometer gives rotor speed; and VEMD monitors other conditions like vibration or related diagnostics, not the specific bending moment on the mast.