How To Connect A CNC Spindle Cable To An HY VFD... 

Thank you for your support. I certainly do. The video's description has links. I also build custom spindle cables. Thank you, Vince

If the 120v, and 240v breakers are sharing the same ground bus in the electrical box its not possible to have a ground loop as their sharing the same central grounding point. Also remember all the double cable's shield drains are only terminated to the ground bus on one end. This prevents ground loops. Thank you, Vince

Thank you for your support. You're correct. The other option to reverse the direction of the spindle is to press REV on the digital display of the VFD. Thank you, Vince

The shield drain isn't the same as the ground lead on the spindle's power cable run to the spindle motor. Connecting both of these leads to the ground on the VFD only provides one connection to this ground point for each of the leads (shield drain, and ground lead for the motor). The ground lead you then discuss for the spindle's power connector, and the conduction point of the spindle's body on the CNC chassis to be specific the gantry as you pointed out would then properly add a grounding point to the end users CNC chassis. This ground point then has many variables affecting it being effective such as conduction between all mounting adjoining surfaces to properly allow grounding of the chassis. If for instance any of surfaces are plastic, or anodized, coated then they are not allowing conduction to the remaining portions of the CNC chassis, in which case these areas of the chassis should be using a "Star Point" ground to ground the entire unit. CNC chassis don't come from the factory grounded ever, so if an end user decides to ground their chassis aside from mounting their spindle to their Z axis mount which 98% of end users don't ever do then they may only have potential for a "ground loop" if they don't pay attention to the spindle being grounded at the VFD end. Attention to detail as you just pointed out is everything. Thank you, Vince

@@corvetteguy50 So in a nutshell what i can conclude is that at the spindle side, the spindle should be conductively isolated from the metal surfaces of z axis slider plate and thus getting in contact by any other metallic surface of y axis to prevent it from getting grounded from machine gantry side. Am i correct?

That's not what I typed. Please reread what I explained. If you plan on grounding your chassis independent of your spindle then yes, you would isolate the spindle. This would essentially make no sense as the chassis is required to be grounded as well, and using the spindle as a ground terminal eliminates the work of having to ground the CNC chassis as a separate entity. The only time you would need to ground the chassis by itself is if the end users Z axis uses nonconductive components/coatings not allowing grounding to be achieved by simply mounting your spindle. Thank you, Vince

@@corvetteguy50 What i want to say is the Sheild wire in both the cases still grounded at one end? like, Case:1 the spindle is conductively isolated from Chassey thus the ground at vfd is the only point Case 2: When spindle is also grounded with chassey, so the sheilded wire is only connected to ground at vfd side but it is also connected to wire (Ground of spindle) which is connected to 2 different points. So technically is the sheild wire still grounded at one end (vfd side)?

If the spindle's power cable is grounded at the spindle motor's terminal 4 using one of the cables leads, and then that lead attaches to the VFD's ground bus along with the shield drain of the cable being connected only at the VFD end the unit is grounded correctly as the shield drain, and ground lead are both grounded to the same single point which is the ground bus on the VFD end. They're not connected twice as the cable's ground lead. and shield drain are both utilizing the same single ground point which is the VFD's ground terminal only. The chassis of the CNC is to either be grounded by itself as I discussed in the previous explanations, or to be grounded by using the spindle through conduction that we already identified. This is pending of course the Z axis for the spindle for the end user's CNC chassis is able to do so without any insulation obstructing conduction. If the Z axes once again isn't conductive where the spindle mounts, then grounding the CNC chassis is to be done separately as a single unit. If you require more support on the topic we can setup a consultation. Please contact me using the video's description above. Thank you, Vince

Thank you for your support. Yes, if you're using the HY VFD you're correct in what you wrote. Thank you, Vince

@@corvetteguy50 ok thanks, 👍

would that be the same for australia 220v cheers @@corvetteguy50

Thank you for your support. Terminal location 9 on the HY VFD is allocated to ground which means the ground from your spindle's power cable is to use this terminal along with the spindle's double shielded cable drain lead to dissipate any EMI. Thank you, Vince