Which DEC function is available when the DEC is in lockout?

Which DEC function is available when the DEC is in lockout?

• A. NG Limiting
• B. TQ limiting
• C. Rotor Speed Hold
• D. NP overspeed protection

Answer: (D)

When the DEC is in lockout, active DEC control functions are disabled, but a safety protection that monitors rotor speed remains available. NP overspeed protection is designed to operate independently of DEC command to prevent the rotor from exceeding its maximum safe speed. It acts as a last line of defense, tripping or limiting NP to keep rotor speed within safe margins, regardless of the DEC’s state. The other limiting and control features, such as limiting NG or torque and holding rotor speed, rely on the DEC’s active control; without the DEC, those functions aren’t available, so NP overspeed protection is the protective function that stays operative during lockout.

When the DEC is in lockout, active DEC control functions are disabled, but a safety protection that monitors rotor speed remains available. NP overspeed protection is designed to operate independently of DEC command to prevent the rotor from exceeding its maximum safe speed. It acts as a last line of defense, tripping or limiting NP to keep rotor speed within safe margins, regardless of the DEC’s state. The other limiting and control features, such as limiting NG or torque and holding rotor speed, rely on the DEC’s active control; without the DEC, those functions aren’t available, so NP overspeed protection is the protective function that stays operative during lockout.