Episode #10: What Is A Mains Filter?

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Continuing on talking about electrical noise, I often times have suggested mains filters to customers and they say, “Well I'm not shipping my system to Europe so I don't need it.”  But there are very good reasons for putting a mains filter on your system even when you're not shipping it to Europe.  Let's take a look at this.  I'm Cory Foster at Valin Corporation. 

Let's talk about a few reasons for having mains filters on there.  One of them is, of course, if you want to ship internationally and you need CE compliance.  Here's a graphic on the right-hand side from one hardware installation guide from one manufacturer that I discussed at great length in my last episode, Episode 9.  Check that out if you want to understand it in more detail.

Another reason is to reduce the electrical noise output.  And again, in the last episode I talked about this greatly.  You don't really reduce the output so much as you manage that output and control the path of that electrical noise.  That, of course, is the reason for the CE(EMC) compliance.  But it also may be that you're having a problem in your system, or a system next to it, or some other system.  It could be bouncy sensors.  It could be feedback problems.  There could be a number of other things going on that you don't even know are electrical noise.  

fig 1 electrical noise
Another reason that people don't think about is to protect against the input of electrical noise.  Your system may work fine in your clean controlled environment in your facility.  But when you ship it to your end-user, your customer, or another facility, you may find that you start having problems because there might be dirty power there.  For example, the power grid may not be as clean as it was in your facility.  Also, there could be external noise sources that are in that facility that weren't where you produce the system.  There could be welders right next to it.  There could be VFDs, pumps, HVAC.  While those aren't your problem, guess who gets the blame?  You do!  Your system gets the blame because your system is the one that's not working.  So, when you measure it in your system, the ground may look like this:
fig 2 electrical noise

But then when you get it to the new location, your ground may look like this.  Really dirty! 

So, I suggest putting a mains filter on there.  That few hundred bucks, five, six hundred bucks maybe, is not worth the hassle of having to deal with this noise that you don't know is going to be there.  I'm Corey foster at Valin Corporation.  Give us a call.  Drop us an email.  I hope this helps!

If you have any questions and are wanting to know more, reach out to us (855) 737-4716, or fill out our online form.