First off I know almost nothing about electronics.

I recently received a Kasuga Cnc mill that was in the process of having the control switched over to gecko drives and mach software.

I also just got a American Rotary phase converter.

Now the problem is sometimes (ever 4 to 5 times) I turn the spindle on, the relay (I think?) shoots sparks off and seems to be melting the contact. I have no clue where to start.

Could it be bad leg on the phase converter? the machine ran within a year at another shop and SEEMED to be fine.

Could the relay be old and bad? where would I find another?

Thanks,
Matt