Power Supplies External to Control Box

[Mr.Hotwire]

Has anyone done this? I'm going to try and keep the control box as cleanly wired as possible, and thought about having the power supplies (2 x 48v, 24v, and 5v) in a separate box. Thinking that might help with electrical noise, and cooling.

[spillage]

That’s kind of what I’m doing... two boxes side by side, one with power supply for the axis drivers and the VFD, and the other with the small power supplies for the controller and accessories, the controller and the drivers. potentially noisy stuff in one box, the clean stuff in the other box... All cables shielded.

[A_Camera]

Has anyone done this? I'm going to try and keep the control box as cleanly wired as possible, and thought about having the power supplies (2 x 48v, 24v, and 5v) in a separate box. Thinking that might help with electrical noise, and cooling.

I have external PSUs to power my CNC. In fact, two of them, one for the CNC movement and one for the linear actuators used for lifting the CNC up. I am in the process of building a third one dedicated for the 4th axis, it will supply 48V 7A, which is enough with good margin for the 3A motor.



Here you can see the control box with the electronics and above that is the PSU box supplying the power. The Linear actuators have a separate 12V 82A PSU, but that's not visible here.

[beefy]

This thread has got me asking the question:
Does having the power supply, drives, electronics all in one box cause issues due to noise.

I've seen quite a few systems where everything is in the one box, yet most noise issues seem to be fixed by proper grounding techniques, screened cables, etc.
Does anyone know of any cases where noise related issues were sorted by moving the power supplies to a separate box.

I've got a nice shiny big electrical box and am thinking of having everything inside. That did get me wondering about noise.

[ger21]

I would think that every industrial machine you'll see will have everything in one box.

[spillage]

For me, everything wasn’t going to fit in a single box that was suitably sized for my machine, so two boxes made sense and allowed me to segregate items that are potentially more noisy from those that are more sensitive to noise, and allow for a neater/less crammed layout.
In a bigger box you can strategically place items to gain the separation to avoid noise effects.

[Mr.Hotwire]

I didn't think I was going to get it all into one box either. But.. with some "Creative arrangement" I was. things are stacked, but not in a way that compromises anything. Ill take pics later on this weekend.

[A_Camera]

I would think that every industrial machine you'll see will have everything in one box.

I really doubt this. "Industrial machines" come in many shapes and sizes and there is no self justification in stuffing one box full with all the needed electrical installations in that single box. Maybe you mean in one cabinet, not one box, which I guess is the case many times, and in which case there are several boxes in that cabinet. But I have actually seen industrial, large CNC machines with electronics spread out for practical reasons also, since in that case it was easier and cheaper to wire that way than having everything in one cabinet. Generally speaking, it is not a good idea at all to mix low voltage equipment with high voltage devices in one and the same box, but in some cases it is more practical than having things separated in several boxes.

[ger21]

Yes, "cabinet", not box. But no boxes in the cabinet.
I've used a few $150,000 routers in the last 25 years, and have looked at a lot more pre -purchase. And getting another new one in a month or two.
All electronics are always in one big cabinet. Power supplies, servo drives, VFD's, and everything else.

[Spuds]

I agree with Gerry.
Proper placement, routing, conductors and grounding strictly adhered to is key.
Only things I typically see mounted externally are transformers and disconnects.