[QuantumCNC]

Hello All,

I'm struggling to find the best method of mounting my power supplies in my enclosure. The mounting panel is aluminum and i'm going to be mounting SuperPID, KFLOP/KSTEP combo, 48VDC power supply, 3 X 5VDC power supply, and a few breakout boards for rj-45 connector, 26 and 16 pin connectors. There seems to be plenty of room but i'm unsure of the proper way to mount everything to provide the best grounding configuration.

For ease of maintenance I was thinking I could build a mounting plate for each power supply allowing me to mount using standoffs, otherwise it seems the power supplies would need to be mounted to the mounting panel directly and then the panel mounted into the enclosure.

Maybe this is desirable for some grounding reason? If so, should my mounting panel be used as a common ground for all my boards?


Thank you for any help that you can provide.

[Al_The_Man]

When you have a lot of hardware to mount in an enclosure it pay to pick up, S.H. if necessary, a commercial style enclosure that has a removable back plane, this way you can fit everything on the panel before installing into the enclosure.
Although its seems you are going this route, everything should be bonded to the back plane.
Also see this on grounding and bonding.
http://www.automation.siemens.com/do.../emv_r.pdf?p=1
Al.

[QuantumCNC]

This is starting to become a bit clearer. When you refer to 'everything should be bonded' do you mean grounded? And when you say 'everything' does this include power ground and ground on the electrical boards? I know there is a difference between earth ground and 'signal' ground, but i'm not entirely sure on how to make the determination as to which is which.

Thank you

When you have a lot of hardware to mount in an enclosure it pay to pick up, S.H. if necessary, a commercial style enclosure that has a removable back plane, this way you can fit everything on the panel before installing into the enclosure.
Although its seems you are going this route, everything should be bonded to the back plane.
Also see this on grounding and bonding.
http://www.automation.siemens.com/do.../emv_r.pdf?p=1
Al.

[Al_The_Man]

Earth Ground is the metallic chassis or metal mounting of the unit, the term Ground is usually used now for any voltage common, in most units, this comes as isolated from earth ground.
Whether you subscribe to earth grounding various supply commons is purely personal preference, as long as the unit allows it electrically.
Personally I generally make a point of E. Grounding these commons where possible.
The Siemens paper shows how to bond various earth ground points called equi-potential bonding, this applies to all metallic parts of the machine and motor frames, these ground conductors normally come back to a central point in the enclosure where they are connected to a star point ground plate, together with the service ground.
As past posts have shown, good grounding and bonding practice has eliminated spurious noise problems.
Al.

[mactec54]

QuantumCNC

Here is a Photo of how I mount,these types of Power supplies,which are similar to what you have, I think Al.has covered the Grounding/Bonding, Correct Grounding & wiring in general will eliminate any noise problems, that most hobby builders seem to have problems with

[QuantumCNC]

mactec54,

I like the picture, it gives me a few ideas as to how to mount mine. Although I have a limited set of tools and fabrication of such a mounting panel might be a challenge. At the very least I was thinking of cutting a piece of aluminum plate, mounting the power supplies to the plate and using stand offs to mount the plate to the panel. I only have one large power supply and the other four are rather small.

If you don't mind me asking, what are you using to join the common ground/live wires together?

[mactec54]

QuantumCNC

I make the Terminal Blocks, what you see in the photo the 110/120V ac is a 4 to 1, meaning it can have 4 power wires, 4 neutral wires, 4 Ground wires connected on one side of the terminal Block & one for each out the other side, this keeps wiring things like this tidy

The low voltage DC side is similar but only ( 2 ) Terminals ( 1) for the Plus +/Minus - wires, this is a 4 into 1 also

[Al_The_Man]

What I use is the DIN rail mount terminals, makes a neat job, they have the advantage of using a copper bar across the centre to common up the terminals, also allows entering the terminals from both sides without doubling up on connections.
This example shows the ground type, the same principle works for +v & commons etc.
Lot of 10 Weidmuller WPE 2 5 Terminal Blocks | eBay
Al.

[mactec54]

Al_The_Man

I use the same DIN rail mounts as well, with the combination of my terminal blocks makes for a lot less wires running everywere