Had an E/C call today and ask how the Code addresses the following:
He has (1) 20 HP Drive feeding (2) 10 HP motors. He says the equipment manufacturer calls for that arrangement. The drive has only the one output.
THe design calls foe a fusible disconnect ahead of each motor (on the load side of the VFD).
It seems to me that he would need to protect the drive input per nameplate. (I believe it calls for a 40 map circuit).
In addition he needs overload protection for each motor.
This leads to my first question: Can he accomplish overload protection by sizing the fuses in his disconnect per 430.32(A)(1) ?
Second question: Would over=temperature protection be required for each motor per 430.126(B) ?
Third question: Will the fuses in his disconnect suffice for motor shot-circuit protection ?
He has (1) 20 HP Drive feeding (2) 10 HP motors. He says the equipment manufacturer calls for that arrangement. The drive has only the one output.
THe design calls foe a fusible disconnect ahead of each motor (on the load side of the VFD).
It seems to me that he would need to protect the drive input per nameplate. (I believe it calls for a 40 map circuit).
In addition he needs overload protection for each motor.
This leads to my first question: Can he accomplish overload protection by sizing the fuses in his disconnect per 430.32(A)(1) ?
Second question: Would over=temperature protection be required for each motor per 430.126(B) ?
Third question: Will the fuses in his disconnect suffice for motor shot-circuit protection ?