VFD is blowing my RCD

[Mr*Beaver]

Good evening,

I'm working on my first CNC build previously I have used and heavily modified a shapeoko. I'm in the final stages of my build (putting everything back in the garage and tweaking). Over the weekend I took my 2.2kw Chinese spindle and Huanyang off my shapeoko and fitted it. Thinking this would be a simple job I hooked it up the same way it had been connected.

The PWM going to the VI, ACM going to ground and DCM and For shorted - upon stating a job it would start and stop on stop.

Now I'm running of an Arduino mega board with external drivers and electronics. When the For and DCM are shorted if I turn the power of the VFD my RCD will blow within a few seconds.

I then shorted with a 2k resistor which actually worked. However I have been told I should use a relay. I went off and bought a 5v low voltage trigger relay rated at 10a 240v and now have that hooked up with For and DCM being linked when the relay is triggered.The relay is powered from the USB powered ardunio. Whilst this works if my usb disconnects for any reason my RCD trips. It's almost as if the surge of the power stopping is triggering the rcd, and previously it was the surge of it starting.

I've had the same vfd and spindle setup for almost a year and not had this issue.

In an ideal world this would not happen. I really don't like tripping the power in my house even if it is a unlikely situation/cause.

And here is a picture of my build :D it has a 80 x 80 x 15 cut ability. I designed and cut the entire frame on my shapeoko 3.