[cadguy247]

First let me say that I know absolutely nothing about electronics, so I apologize for the basic question.

I want to relocate the control panel on my PM-25 from the head to outside the enclosure. Do I need to run a ground from the panel back to the mill or some other place or will grounding to the box itself be fine? I would think that to the box itself would be ok since that's how the control boxes I purchased are grounded, but would like to make sure before I blow something up

Thanks in advance

[Fastest1]

As long as you either ground the box independently or physically attach the box to a grounded section of machine itself, you will be fine. I am doing just that right now.

[cadguy247]

As long as you either ground the box independently or physically attach the box to a grounded section of machine itself, you will be fine. I am doing just that right now.

so attached the ground to the metal casing of the control panel will be fine? Sorry, like I said I know nothing about electronics... It's actually kind of embarrassing sometimes

Also, if the control panel is no longer attached to the mill, does the mill need to be grounded to anything too? I wouldn't think so, but with the addition of the motors and homing sensors I wonder if it needs to be grounded and if so, what is the best method to do so?

Thanks

[Fastest1]

It would be best to remove the paint from both surfaces if you were to mount the control box to the machine frame (just enough to insure bonding). The mill does not need to be grounded to actually operate but for your safety it would be best. There is still a spindle motor with high voltage, if it goes South and shorts out, it would be best if its path isnt thru the operator as he investigates why the spindle isnt moving.

Dont feel bad about your lack of electrical understanding. That is why the forums exist. I am at a loss as we get in a little deeper.

[cadguy247]

It would be best to remove the paint from both surfaces if you were to mount the control box to the machine frame (just enough to insure bonding). The mill does not need to be grounded to actually operate but for your safety it would be best. There is still a spindle motor with high voltage, if it goes South and shorts out, it would be best if its path isnt thru the operator as he investigates why the spindle isnt moving.

Dont feel bad about your lack of electrical understanding. That is why the forums exist. I am at a loss as we get in a little deeper.

Thanks!

So I think I would like to ground the mill then, how should I go about this? Just run a wire from a bare spot on the mill to the ground of a wall outlet?

[Fastest1]

The best procedure is called a "Star ground". This is where you create a central grounding point. Bring your ground from the wall outlet to a single bolt or screw. Tie all of your grounds to this point, shields from your stepper and limit wiring attach there too. This minimizes the potential for noise to cause false triggers in your system. That includes grounding the machine itself. control box and anything metal attached or a part of the system.

[Al_The_Man]

+1 on post #6
This is also called equi-potential bonding of all metalic parts of the machine,
http://www.automation.siemens.com/do.../emv_r.pdf?p=1
Al.

[Fastest1]

+1 for Al stepping in! Here is the man with the understanding. I wouldnt know what a star ground was if it werent for him.

[cadguy247]

Thanks guys for all the help!

[Fastest1]

We want to see you successful in your build and post some machine porn videos!

[TroyO]

I used something like this.... not a star but all grounds hit this bar and get screwed in place.

Square D by Schneider Electric PK7GTACP 7 Terminal Ground Bar Kit - Grounding Bar For Circuit Panel - Amazon.com

I believe it serves the purpose, but wiser minds may see something I missed. I just couldn't fathom how to get 10-15 grounds all on ring terminals and screwed to a single point.

[Bill1959]

I

[Fastest1]

TroyO, i think this is acceptable. Din rails are used that way. They sell individual ground blocks that use the rail as the ground.

[Al_The_Man]

I used something like this.... not a star but all grounds hit this bar and get screwed in place.

I believe it serves the purpose, but wiser minds may see something I missed. I just couldn't fathom how to get 10-15 grounds all on ring terminals and screwed to a single point.

Star Ground does not necessarily mean all the terminations under one screw, the Square D link is a typical method.
JUst all grounds at one central point.
I often make up mine with a piece of copper bar drilled and tapped #10-32 etc to take all the screw terminations.
Al.