Noise for the electronics.

Status
Not open for further replies.
E

ENI

Member
Location
Lathrop CA
Occupation
Facilities director.
The structural steel bond is creating a lot of noise in the control panels for the equipment we work with, is there an alternative way to bond the building? or a filter that will get rid of it?
 
Could it possibly be a bad power supply or something else in the equipment? Or does it happen on every install you do? Maybe some ferrites in key locations could help?
 
ENI said:
The structural steel bond is creating a lot of noise in the control panels for the equipment we work with, is there an alternative way to bond the building? or a filter that will get rid of it?
Click to expand...
Welcome to the forum.

What bond are you referring to, one at the service or at the control panel?

As long as there is a proper EGC run with the circuit, that's all you need.
 
LarryFine said:
You mean GEC.

I was thinking unwanted ground-looping.
Click to expand...
Yes that’s what I meant. To fix ground noise on your electronic equipment try replacing the equipment grounding conductor for the receptacle powering your electronic device with an isolated ground which means you buy an isolated ground receptacle and run an insulated ground from the receptacle isolated ground termination all the way to the panel ground bus without splicing to any other EGCs or structural steel
 
The steel could very well be noisy and that would not be uncommon. It is serving it's purpose plus some unintended but otherwise occurring purpose as well.

The noise is not getting though the control power supply. That is not happening.

The noise could be picked up by the IO field wiring as well as control IO wiring passing too close to the power wiring inside the control cabinet. That would be very common and likely to happen.

You could try a two front approach of looking for the steel noise source and trying to mitigate that, which could prove to be too big an apple to bite. The other approach is your control system field wiring is supposed to be noise immune. This was a problem discovered in the 1980's and solved back then.

Fast forward to the 1990's when all those guys who knew that got fired, then forward some more to today when noise induced problems of the 1980's are recreated by today's job holders. Likely your IO control wiring supposed to be noise immune is not and that is where the problem source may originate.
 
IME, it's almost never a "ground" problem; its an equipment and connections problem. For instance, using the protective ground (AKA EGC) as a signal reference- might work great in a single cabinet but it'll be lousy for anything more than a few feet away.
 
Jpflex said:
Yes that’s what I meant. To fix ground noise on your electronic equipment try replacing the equipment grounding conductor for the receptacle powering your electronic device with an isolated ground which means you buy an isolated ground receptacle and run an insulated ground from the receptacle isolated ground termination all the way to the panel ground bus without splicing to any other EGCs or structural steel
Click to expand...
It seems like the best path to take for this problem. I’m going to try that. Otherwise I guess you’ll be hearing from me again. Thanks everyone. All great suggestions.
 
LarryFine said:
Welcome to the forum.

What bond are you referring to, one at the service or at the control panel?

As long as there is a proper EGC run with the circuit, that's all you need.
Click to expand...
At the control panel. My thought on this is that there are several large circuits that are all controlled by these panels. There is the two press motor 250 A each the hoist motors 150A x 2. And an assortment of smaller circuits distributed among conveyors and furnace controls chiller loop controls and various pumps. All this is likely to have create noise, but nothing a good ground couldn’t take care of but it hasn’t so far. We have not tried a dedicated ground yet but as was suggested, it will be our next step although the service is very far from where the equipment is.
 
ENI said:
It seems like the best path to take for this problem. I’m going to try that. Otherwise I guess you’ll be hearing from me again. Thanks everyone. All great suggestions.
Click to expand...
I’m not certain but the isolated ground and circuit wires supplying this piece of equipment may have to be in its own conduit such as ungrounded conductor(s), grounded conductor (neutral), and isolated or dedicated equipment ground conductor mentioned so that these wires are not sharing conduit from other wires different circuits. But if not don’t worry so much as I think it will still work for your purpose.

Also the receptacle box can be isolated from the upstream conduit by a nonmetallic fitting, this way the ground to your device is totally independent and isolated from other EGC equipment ground conductors.
 
What sort of noise are you getting and what sort of issue is it creating on the equipment?
If the equipment is susceptible to RF interference, the structural steel can act as a large antennae amplifying it's effect. Isolation equipment from the structural steel might fix it if that is the issue.
 
Jpflex said:
Also the receptacle box can be isolated from the upstream conduit by a nonmetallic fitting, this way the ground to your device is totally independent and isolated from other EGC equipment ground conductors
Click to expand...
If there is an IG feeding the equipment isn't the equipment already isolated from the mechanical EGC used for bonding the box?
 
Status
Not open for further replies.
Top