For normal shutdown operations of the rotor brake, what NR condition is specified as the maximum?

For normal shutdown operations of the rotor brake, what NR condition is specified as the maximum?

• A. NR below 40%
• B. NR below 60%
• C. NR below 20%
• D. NR below 50%

Answer: (A)

The rotor brake is designed to be engaged only when the rotor is spinning at a low speed, so the brake can absorb the stopping energy without excessive heat or stress on the system. For normal shutdowns, the procedure specifies a maximum rotor speed at which you apply the brake, to keep the engagement within the brake’s limits. That means the brake should be used when Nr is below 40%. Engaging the brake at higher rotor speeds would subject the brake and drive train to too much load and heat, risking damage. The other thresholds exceed this safe limit, which is why they aren’t the correct choice.

The rotor brake is designed to be engaged only when the rotor is spinning at a low speed, so the brake can absorb the stopping energy without excessive heat or stress on the system. For normal shutdowns, the procedure specifies a maximum rotor speed at which you apply the brake, to keep the engagement within the brake’s limits. That means the brake should be used when Nr is below 40%. Engaging the brake at higher rotor speeds would subject the brake and drive train to too much load and heat, risking damage. The other thresholds exceed this safe limit, which is why they aren’t the correct choice.