Hello,

Quote Originally Posted by kostas1 View Post
What do you mean by 'housing'?
Well, the spindles housing or "body" - basically the whole outside of the spindle...

Quote Originally Posted by kostas1 View Post
The power wiring of the VFD to spindle is the following: I wired the U,V, and W VFD outputs to the 3 pins of the spindle and I left the pin 4 non-connected.
Could it be this the cause ?
Also the ground terminal of vfd has been connected to the ground from the wall.
No - but you're playing with your life if you just ground the VFD but not the spindle itself...
Again: VFDs can kill you - even if disconnected the input capacitors may still be charged to about 325V for a while.
I'd also not rely too much on things some guys tell you over the internet if you're not familiar with this kind of equipment.
Give both spindle and VFD to an electrician - he has the equipment to see what is defect and whether it makes sense to repair or not.

The part is most likely a varistor like Al_The_Man said.


Christian