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

[@philipchristian9935]

Thanks for the info! Guessing you don't sell the cable anymore?

[@corvetteguy50]

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

[@dd_Dedsec]

Here you have coupled the spindle ground and the shield ground wire together, so basically when you are connecting that at ground bus from vfd side, isn't the shielded wire now connected to ground from both ends just see and the reason why i am saying this is because at the other end which is your spindle is metallic body and that body is always in contact with the gantry metallic surface and the whole gantry is grounded thus creating 2 different ground points that can cause ground loops. Correct me if i am wrong or do we need to conductively isolate spindle from getting in contact to metallic chassey of gantry on the y axis to prevent it from making the spindle side as another ground point.

[@corvetteguy50]

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

[@dd_Dedsec]

@@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?

[@corvetteguy50]

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

[@dd_Dedsec]

@@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)?

[@corvetteguy50]

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

[@LyleWallaker-oz2gr]

Hi Vince, great info in this video, I’m looking to upgrade my CNC from router to spindle/vid but I’m thinking 20’ cable is way too much for me. Do you have a link to a 10’ cable that is preassembled for installation?

[@corvetteguy50]

Thank you for your support. I don't have a link in my store as each cable is quoted based on my clients female spindle power connector as each different one requires a different amount of labor to install. If you would like a quote please email me a picture of it, and I'll forward the quote. Thank you, Vince

[@AntiVaganza]

Hi Vince, Binging your videos now as he have to retrofit a used machine. Anyhow, I have been scouring the internet and one thing still confuses me, it seems some people say to never terminate the shield at both ends and some do terminate them at both ends. It's still a bit unclear to me, how you approach this? Also, my limit switches (inductives w. three leads) are not shielded. Should I replace the cable with shielded cable for those? And on that same note, would it be ok to share the power and ground between the switches, so I can use connectors with fewer pins? If it didn't make sense, then say I have 6 switches, that would be 18 pins on the connectors between the machine and the cabinet as each switch has three wires. But only one of them is a signal wire, so that's just 6 wires for the signals. And then I could run power on two more pins and the total would be 8 pins - instead of 18 pins.

[@corvetteguy50]

The answer to your first question is back in 80-90's all shielded cables regardless of their applications were grounded on one side only to avoid potential "ground loops", and now many all of a sudden claim to ground both ends. This information started from VFD manufacturers. The same ones that released their own kits for this specific purpose. Seems like a coincidence huh? I look at this from the point of "if it isn't broke then don't fix it" There's not a single Google post of someone claiming their VFD was damaged from EMI from not grounding both ends of their cable with good reason as it was a tried, and true method that worked in the decades I listed. I still practice grounding only one end as it was best practice then, and in my opinion still is. "Daisy Chaining" isn't best practice, and in your example for your switch connections a terminal splitter is to be used in best practice. All cables on your system in best practice supporting switches, motor signals, and anything carrying control signals should be double shielded. If the system isn't using them then replace those cables with the correct ones. Thank you, and Happy Thanksgiving! Vince

[@ericbuzz]

Vince, great info but I wonder if the Controller/Machine (120V) and the VFD (240v) are on separate circuit breakers will there be possible issues with ground loops? should I for example disconnect the ground (green) wire going into the 120v wall socket and connect it to the 240v sockets ground so they share the same line?

[@corvetteguy50]

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

[@sateeshum394]

three phase motors run in reverse if the pairing changes isn't it, it just takes two wires to change though.. on spindles which support reverse (counter clockwise) one may need to be careful

[@corvetteguy50]

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

[@martyn1678]

hi, i have a question 😓 please dont bit my head off i have search the internet for a answer to no avail, where do i connect the earth from my 3pin uk socket. Do i connect it to pin 9 so id have 2 ring connectors one from my uk wall sock and one from the spindle? thanks martyn

[@corvetteguy50]

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

[@martyn1678]

@@corvetteguy50 ok thanks, 👍

[@gavinkealy5882]

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

[@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