magic smoke escaped from my chinese VFD

[IanParkin]

When you say you tested it with no load ? does that mean you started it with no motor connected?

[paulus.v]

No, running the spindle with or without any tool inserted and without machining any material.

And yes now I remember that when I connected the water hose some days ago I forgot to reconnect the motor power plug and started it for a few seconds without the motor.

After that it has run ok for about half an hour until I have applied some load (4mm end mill 3mm deep in acrylic), the bit didn't broke and the cut was clean.

[EddyCurrent]

How long is the cable between vfd and motor ?

Edit: I see from a previous thread you mentioned 5.5m, that should not cause any issues. Long cable runs could give you flames at the vfd.

Whats the full model number of the vfd ?

I think those red wires in the photos are the ones leading down to U,V,W terminals so my advice would be to check the spindle motor wiring for short circuits. This could be either inside the motor windings, the plug/socket on the motor, the motor cable.
Before you do anything, disconnect the wires from the U,V,W terminals and check the wire using a multimeter on ohms. This is because sometimes if you start at the motor end, just moving the wires can take the fault away and you will think it's fixed. With the meter connected move the wires around to see if a short circuit comes and goes, it could be between any of the three wires.