In NR power-off, the transient torque is specified as which value?

In NR power-off, the transient torque is specified as which value?

• A. 90%
• B. 108% (10 sec)
• C. 110% max
• D. 80% (10 sec)

Answer: (D)

Torque during a power-off transient is kept low to protect hardware as speed decays. For NR power-off, the transient torque is limited to 80% for 10 seconds. This conservative limit helps absorb inertia and prevent large shocks to the drivetrain and generator during shutdown, keeping control responses stable when power is removed. Higher limits would allow bigger torque spikes at the moment of turn-off, increasing wear, stress, or risk of instability, which is why 80% for 10 seconds is specified.

Torque during a power-off transient is kept low to protect hardware as speed decays. For NR power-off, the transient torque is limited to 80% for 10 seconds. This conservative limit helps absorb inertia and prevent large shocks to the drivetrain and generator during shutdown, keeping control responses stable when power is removed. Higher limits would allow bigger torque spikes at the moment of turn-off, increasing wear, stress, or risk of instability, which is why 80% for 10 seconds is specified.