controller RF interference

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controller RF interference

Postby stillvodka » Sat Apr 06, 2019 10:38 pm

Hello all

Seeking some advice
I am about to purchase one of these https://www.sutronics.com/ProductDetail ... =PC240-20P

In the description it say that it will need a suitable RF interference filter ,

Do I really need the RF filter ? with it being used outside in the shed ,

I am sure I had one of these controllers a number of years back , I cant every remember fitting a filter

Thanks
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Re: controller RF interference

Postby Yummyrum » Sat Apr 06, 2019 11:06 pm

It won’t stop it working . It will just stop it causing interferance .

All phase controllers generate a lot of interference .I’d say they are covering their arse to comply with FCC interference rules . To be honest , it would ‘t have cost them more than a dollar to add the filter components .

Just don’t expect you or your neighbours to listen to any AM radio stations while its running .

There is a lot to be said for using zero mains crossing SSR’s and controllers like Auberins DSPR1 .... not the cheapest puppy but very FCC compliant .

Did I say I used to be a HAM radio guy . :?
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Re: controller RF interference

Postby stillvodka » Sat Apr 06, 2019 11:52 pm

Thanks for the reply yummyrum

So a filter is not really needed then ? It's not going to cause problems

Just out of interest, if you were to install a filter , what one would you use and where would it go on the wiring

Thanks
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Re: controller RF interference

Postby shadylane » Sun Apr 07, 2019 9:48 am

I wouldn't worry about RFI unless your a ham radio operator or you live near an airport with a ILS
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Re: controller RF interference

Postby shadylane » Sun Apr 07, 2019 9:51 am

stillvodka wrote:Just out of interest, if you were to install a filter , what one would you use and where would it go on the wiring
Thanks

Plan B
Instead of a filter, put the controller in a grounded metal box
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Re: controller RF interference

Postby stillvodka » Sun Apr 07, 2019 11:52 am

shadylane wrote:
stillvodka wrote:Just out of interest, if you were to install a filter , what one would you use and where would it go on the wiring
Thanks

Plan B
Instead of a filter, put the controller in a grounded metal box



Thanks shadylane, That is what I will do
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Re: controller RF interference

Postby Kindafrench » Tue Apr 09, 2019 11:05 am

If you‘re interested in the subject, google snubber circuit. But I wouldn‘t design or add one myself. It’s usually a capacitor and a resistor in series, parallel with the triac. Maybe you could use a noise supressing coil. Easy to build if you find a suitable ferromagnetic coil (broken computer power supply for example). Plugin noise filters are available online. There is no big magic inside them. A shielded metalbox, like said before helps. My poor solar radio gets the noise from my controller on AM, wide frequency range. 10 meters away from the controller, the noise is still there, but much lower intensity. No RF freaks around, as far as I know. I‘m gonna listen to it from a more far distance later.

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Re: controller RF interference

Postby Kindafrench » Sat Apr 13, 2019 8:12 pm

Some news about the SCR RF interference. As I tested the controller / heating element function, I took my radio on a garten trip. The controller was set to a range that I could hear 50 Hz hum in the boiler. About 50 meters away, I could hardly hear the hum anymore. I can imagine that there is still some effect at nearby neighbors range.
My SCR is one of these 4 kW ones, in a small aluminium caseing. I put it in an old computer power supply housing. All grounded.
There could be a wrong resistor in the snubbing circuit, as Big Clive said. No idea if that causes more humming.
More details on the SCR here: https://www.youtube.com/watch?v=_4PwYm_7HKg&feature=share

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Re: controller RF interference

Postby bolek » Mon Apr 29, 2019 1:40 pm

Specially to Stillvodka, Shadylane and Kindafrench

Metal box and RC snubber not reduce distortion from this regulator, band can be end at ~50MHz. This noise is called "conducted", it goes everywhere via wire who start to work as big antena also. Here is a bit of theory http://www.kemet.com/Lists/FileStore/PartnerHub%20PTM%20AC%20Line%20Filters%206.18.14.pdf

If neighbor at the other end of town like to talk through CB then situation can be not nice :D It's demand from local law. In Europe this neighbor can call to special office and sad man come with antenna and try to find source. So invite outsider to your secret place is not good idea

Is not hard to reduce this distortion. Search for "AC filter" like on picture, schematic is simple, so if you try to buildt it by yourself then you lost maybe 15USD. I think that filter with single 4,7...6,8mH commom mode coil, CX= 220nF, CY=2,2...3,3nF wil be enough. But remember- working current must be suitable to your consuption.
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Re: controller RF interference

Postby Hoosier Shine9 » Tue Apr 30, 2019 8:59 am

Yummyrum wrote:It won’t stop it working . It will just stop it causing interferance .

All phase controllers generate a lot of interference .I’d say they are covering their arse to comply with FCC interference rules . To be honest , it would ‘t have cost them more than a dollar to add the filter components .

Just don’t expect you or your neighbours to listen to any AM radio stations while its running .

There is a lot to be said for using zero mains crossing SSR’s and controllers like Auberins DSPR1 .... not the cheapest puppy but very FCC compliant .

Did I say I used to be a HAM radio guy . :?


CQ, CQ, CQ
Victor Kelo, de Kelo Bravo
not to hijack the thread
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Re: controller RF interference

Postby shadylane » Tue Apr 30, 2019 3:54 pm

"Radio frequency interference"
If there's nobody near by to interfere with
There's no problem. :lol:
On a side note about generating massive RFI :ewink:
I find the sound, sight and smell of Tesla Coil with a rotary spark gap to be quite invigorating "emoji for evil scientist laughing"
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