VFD Protection

[augie47]

Elementary question.
If a VFD nameplate calls for 200 max overcurerrent protection, is there any allowance that allows you to feed it with a conductor smaller than 3/0
(The motor is 100 HP/480v)

 

[infinity]

What is the nameplate input current of the drive?

 

[augie47]

Its not given, but for conversation sake lets say 175 amp

 

[don_resqcapt19]

Its not given, but for conversation sake lets say 175 amp

Then 430.122(A) will require a conductor ampacity of 218.75 amps, requiring 4/0 copper. Note that if the horsepower rating is greater than 100 hp, the VFD instructions may provide a lower input amp rating for the 100 hp motor.

 

[infinity]

Its not given, but for conversation sake lets say 175 amp

Then as Don stated 175 amps*125% for the conductors feeding the drive. The OCPD is typically sized by the drive manufacturer.