What torque is specified for NR power-off transient?

What torque is specified for NR power-off transient?

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

Answer: (B)

When a power-off transient is considered, the test defines how much torque and for how long the machine must withstand the sudden change. The specified scenario uses a torque at 80% of the rated value held for 10 seconds. This level is enough to exercise the drive and control systems during a power loss without pushing the mechanical or thermal limits, giving a meaningful but safe transient response. Higher torque values, like 90% or over 100%, would impose stress beyond what the design typically tolerates in a controlled transient, and different durations wouldn’t match the standard window used to observe the system’s response. The 80% for 10 seconds setting strikes the right balance for a representative power-off event.

When a power-off transient is considered, the test defines how much torque and for how long the machine must withstand the sudden change. The specified scenario uses a torque at 80% of the rated value held for 10 seconds. This level is enough to exercise the drive and control systems during a power loss without pushing the mechanical or thermal limits, giving a meaningful but safe transient response.

Higher torque values, like 90% or over 100%, would impose stress beyond what the design typically tolerates in a controlled transient, and different durations wouldn’t match the standard window used to observe the system’s response. The 80% for 10 seconds setting strikes the right balance for a representative power-off event.