VFD load wiring

[kwired]

"The(re) is not any direct connection between input and output sections of a VFD."

I wouldn't say that. It's not a transformer. There is a rectifier section, a capacitor section, and an inverter section. The same electrons that come in and out of the line side go out and in on the load side.

The rectifier is in a way a check valve and only allows energy to flow one way.

If the DC bus is below full charge, energy flows in, if it is overcharged from energy coming back from the motor it does not go back through the rectifier, and can not until it reaches a level that will cause damages. This is why braking resistors are needed for certain cases, a way to bleed off that excess energy.

Edit: Sorry I didn't read through to last post, I see you figured this out