Re: 500w chinese spindle interference
The first thing I noticed is that your AC supply to the DC PS has been marreted off, (insulated).
Your PS case needs to be earth grounded, the star ground is just that, a star point where all grounds that require to be earthed are connected to, a set of terminals or a plate with holes tapped to take ring terminals etc.
All motor frames should be grounded as well as PS negative terminals if possible in order to avoid random triggering.
Do a search here for my posts on equi-potential bonding. Many over the years.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.