VFD error

[Jonathan]

Check the resistance between each of the UVW terminals and the DC bus, as if just one is short circuited you'll still measure a high resistance between the phase connections.

I wouldn't worry so much about the Chinese VFDs - how many recent threads have you seen where the VFD hasn't worked, due to the product not the user? Also adding a potentiometer to either isn't difficult, so I wouldn't make a decision based on that.

2.2 ohms sounds about right for the DC resistance.

Edit: Also, regarding whether to get vector controlled or not - with vector control you will get more torque from the motor (at mid-low speed) and better efficiency, but if you're currently happy with the torque from the motor then it's not really gaining anything so you might as well go for the cheaper option.