Reducing noise from random sources - Page 1
Forum section: electronics / beginners

author: Saco
author_rank: Contributor
timestamp: January 10, 2021, 10:12:24 am
content: Hello,I know this is a widely talked about topic but it's usually at circuit design time or regarding shitty low-cost equipment in which case its better to just replace them.In my situation I have several appliances that are generating massive noise which I noticed when I couldn't get a PowerLine system going.I have tried to isolate the biggest contributors and I could identify a set of LED lamps (not sure if this amplifies the problem, but they're connected in series).From my searches on the internet, ways to solve the issue include using a UPS, an electrical noise filter or a ferrite core choke.The UPS makes sense as it effectively isolates the LED from the grid, but if I understand correctly the other two options are only meant to filter input noise (please correct me if I'm wrong).So, what would you guys suggest in terms of cost effectiveness?

author: Kleinstein
author_rank: Super Contributor
timestamp: January 10, 2021, 10:30:44 am
content: If you care about EMI, the best is not to use PowerLine LAN. Often it is one of the largest offenders.Besides EMI from other noise sources Powerline network can also be negative effected by simple filters in instruments - some also absorb the crab from the grid, as they may have not much more than a X-cap directly across mains. The filters by itself are usually OK - they don't break the rules. For such instruments an addition series choke can help. Another point is having the network over one fuse or at least 1 phase only. It does not couple well to other phases and the fuses may also dampen the signal.There are different types of LED lamps - some cause EMI problems and some not. Often it is easier to buy the lower noise lamps than to later add fitlers to the lamps.An UPS for the lights is not a solution: The inverters in an UPS are more a likely source of EMI, just next to PowerLine networking. It is more like to avoid an UPS at the computer and have notebook instead.

author: Terry Bites
author_rank: Super Contributor
timestamp: January 10, 2021, 02:42:32 pm
content: LAN over mains is crap.Save your money, don't buy a load of filters or a UPS, buy a good wireless extender or a wireless router.Do you need all over place LAN or point to point? Better still run LAN cables. A UPS will put even more unwanted noise on your mains.If you want to put filters on serious offenders. Best to go with a suitably rated filter that has common and differential mode rejection.

author: Siwastaja
author_rank: Super Contributor
timestamp: January 10, 2021, 06:57:44 pm
content: LAN over mains just sounds a terribly, terribly bad idea. No wonder it doesn't work. The problem isn't at devices "generating" "noise", your LED lights are likely all / most perfectly within the (fairly tight) legislation. It's just that such LAN over mains devices are not supposed to work but may work by luck. They are entertainment.Likely building a classical LAN, wireless or wired, would be far easier and cheaper than trying to properly choose and/or filter each device on mains, including your neighbors.