[Big John]

If it's tripping on overucrrent, what are the current values per phase during a trip? What's the normal running current? Is it belt-driven or direct? Is the plenum shared by any other blowers?

 

[Big John]

I dont highly recommend using a vfd to drive a fan, or blower
due to the fact that loss of power will result in feedback from the magnetic field collapse will create a massive and catastrophic spike back through the vfd and frying it...

I don't follow. How does turning off a blower differ from turning off any other motor load?

You never disconnect the load side of a running VFD regardless of what it's connected to.