Q. What is the Code rule for sizing short circuit and ground fault protection for a motor feeder? A. Feeder conductors must be protected against short circuits and ground faults by a protective device ...

Annex D3(a) of the 2011 NEC provides a good example of feeder conductor sizing. It's more detailed and complex than the simple feeder example in Annex D3. In Annex D3, much of the work is done when ...

Oversizing often happens when engineers try to match the inertia between the load and the motor rotor, so that they can tune the drive’s velocity, torque or position loop relatively tightly to meet ...