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Julius Wilkko
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Discussion Starter · #1 ·
Hi!

Since this subject hasn't been discussed before, I decided to add few lines. It can be useful for some of us home racers. Slotcar motor generates all kinds of electro-magnetic interference (EMI). This interference can be conducted via copper wires from motor to AC socket outlet or radiated directly from motor to surrounding devices. Usually it's radiated RF-interference and visible on TV screen. So, if your kids are racing and at the same time you want to watch Emmerdale or Bold and Beautiful on TV - you may have a problem.


I'm amazed how some manufacturers don't bother to reduce EMI at all. You cannot find EMI-suppression components in FLY, Proteus or Cartrix car at all. Naturally serious racers will remove extra components but for example most common EMI suppression method, 100nF capacitor across motor +/-, does not have any affect on car performance. Chokes such as in NINCO or Carrera won't tolerate excessive currents and should be removed if the car is upgraded with high RPM racing motor.

Here's circuit collection how different manufacturers have tried to reduce EMI

Scalextric/SCX:



NINCO:



Carrera:



Cheap chinese 1:32 set car:



2,2nF = ceramic capacitor, 2,2 nanofarads
22nF = ceramic caacitor, 22 nanofarads
10nF = ceramic capacitor, 10 nanofarads
100nF = ceramic capacitor, 100 nanofarads
6,8uH = choke, 6,8 microhenrys
10uH = choke, 10 microhenrys
22uH = choke, 22 microhenrys

The last car on the list is from cheap track set similar to Artin. Price of the car is 6euros and still it contains 5 EMI suppression components. This is not price issue, so I wish that some manufacturers would take EMI more seriously.

If you have a car that disturbs your family life, all it takes is some inexpensive components and basic soldering skills to reduce EMI. Remember that soldering these components is not 100% cure, but in will suppress some of the disturbance.


Julius

PS.
Serious racers should also pay more attention to this subject. Timing sensors and computers operating your track can also catch interference. Need for EMI reduction will increase with introduction of new digital systems.
 

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Beppe Giannini
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I suppose there's nothing more to be said


I'll just print it and keep it for future reference

Beppe
 

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This is an interesting subject - particularly the following
QUOTE some manufacturers don't bother to reduce EMI at all. You cannot find EMI-suppression components in FLY, Proteus or Cartrix car at all.
I had always been under the impression that UK laws demanded the fitment of EMI suppression to all electric motors. I am still not sure of this and I may be mistaken.

But, if this would happen to be true, then certain manufacturers could be in breach of UK Law in not providing appropriate suppression and we also, as individuals, could be in trouble if we remove that which has already been provided.

Looking particularly at the Carrera and 'cheap Chinese Car', and their comprehensive EMI suppression, one might question why all this is fitted unless at least one of their national sales destinations does not absolutely demand it? It seems safe to assume that the equipment is compulsory somewhere and it then must follow that those cars not so fitted are unable to be sold legally in that area of the world. I'll take a reasonably intelligent guess that one such country would be Germany itself.

Speaking of cheap Chinese cars at €6, I'd be very interested to take a look at the rest of the car if possible. That's the sort of price I like to pay!
 

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Brian Ferguson
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QUOTE I just cut all these off when I get the cars

they seem to sap a little power so I cant accelerate quickly

Translation = "They get in the way when I'm looking for space for my large 'booster' capacitor"...
 

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Well Fergy I wasnt going to put it that bluntly but the vectra IS in bits at the moment, dropping in a new motor.. yes it takes me a week or 2 to do this as i never have what I need or loose something. I need a trip to Maplins OR go to electronics on monday like I always do...


Rob
 

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Hey Julius, good topic idea, thanks. To carify for me, is what you are referring to as a choke the same as a resistor? ie: used to reduce the voltage to run low voltage motors or components? I am a bit fuzzy on the electronics and am trying to sort it all out.
 

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Julius Wilkko
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935 Posts
Discussion Starter · #8 ·
Hi !

Soapy, choke is not a resistor, it's an inductor. In practice thin wound copper wire. Voltage drop across inductor is small, but inductor/choke resists fast voltage transients that try to go through the component. This is how it suppresses EMI. Fast voltage spikes generated by motor are attenuated by choke. What's the difference between choke and inductor then? It's just one of those things where different people are using different terms for the same thing.
Usually electronics world calls small inductors that look like resistors as chokes. When you have a component where copper wiring is clearly visible then it's usually called inductor.

Tropi, it's European CE regulation that dictates the maximum allowable limit of EMI disturbance. Thing is that nobody controls CE regulation. Manufacturer just tells that its product will comply certain CE regulations. If you browse FLY car box you can see letters "CE" there. This means the company has in theory tested its products and they are within allowable limits. Also Proteus Lambourchini box contained CE markings although it's my worst car ever disturbancevice. One can ask have they just printed CE to their boxes and hoped for the best. How can other manufacturers get away with no suppression components installed and others have several components installed although motors are about the same with both.
I'll take a photo of that cheap 6e (£4) car shortly. Mostly I disassemble those and use pinion, motor and rear axle for my Revell easy kit cars.


Julius
 

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Reducing EMI interference? One way is not to buy any records produced by them!


Or another good way of reducing EMI is not to initiate any nuclear explosions!


Ahem...I'll get me coat then...

Actually, if your statement about the suppresion devices not detracting from car performance is correct (and I do not know enough about these things to disprove your comment), the devices still incur a weight penalty. WEIGHT IS THE ENEMY! Unless you can place it were you require it to optimise handling i.e. ballast.

Is it against the law to remove them in the UK? I don't know and quite frankly couldn't give a flying fish. If the plod want to check each and every slot car in the country then there is something sadly wrong with the fabric of society. When there are muggers, rapists, child molesters, gunmen, crackheads, bike thieves at large then a bit of static on a cathode ray tube pales to insignificance


Mark.
 

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Brian Ferguson
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Difflock, caution is advised.
The EMI police are everywhere. They're currently investigating Inte.
You could be next!
 

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I'm just going outside.... I need to go and pick a few things up that may have "accidentally" "fallen" out the window...

now wheres the soldering iron?
 

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capacitors are very light , they may even be lighter than the 2mm of wire and insulator they replace. Don't know about chokes
 

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About EMI control,

In some contries (e.g. Sweden) you can always call a 'signal emission control service' that can send someone who can come and measure what levels disturbances are at in your home. So for example if you get your TV program spoiled due to your neighbours playing (racing?) his latest slotcar he will be asked to stop his activity. Actually he could be fined if he continues his 'signal disturbance activity'...


There is something similar in Germany and Austria I believe due to regulations - but I am unsure how it is practiced...

In the UK - well... we... are supposedly part of europe so... I think




oh I must be doing something wrong since I usually end up adding weight to my cars once I take out the magnet...


 

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Julius Wilkko
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935 Posts
Discussion Starter · #14 ·
Yes ... I knew people wouldn't take EMI seriously
... and some racers seem to even think EMI directive as government conspiracy to reduce their car performance. Beware the EMI police!


But seriously - it's not against the law in any country to remove these filter components. The worst that could happen would be 180Kg bodybuilding neighbour who finally figures out link between your slotcar track and disturbances on his TV screen.


Julius
 

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In a semi-serious vein, Lordjw's advice is very sound and worth considering.

Its not that there are EMI police about hunting for speed crazed slotmaniacs. However, its can be a neighbour using one of those cheap rabbits ears TV aerials who complains to their local MP about intermittent interference while watching "Neighbours". There was someone asking about EMI suppression to solve this exact scenario only a few months back.
 

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Julius Wilkko
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Discussion Starter · #16 ·
Hi!

Here's a picture of that cheap £4 car for Tropi



Usually I just salvage parts for my Revell EasyKit cars. Here's modified Mercedes chassis.



I KNOW !! There are no filter components at the picture, those were installed to the car afterwards. Really. I guarantee i did the soldering. You can send EMI police to inspect me if you have any doubts.




Nice looking and very cheap 18e (£13.50) car.


Julius
 

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Julius Wilkko
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935 Posts
Discussion Starter · #18 ·
Cars are from nordic harware store chain called "Biltema". They have shops in Norway, Sweden, Finland and Denmark.

http://www.biltema.se/index.asp

in "sök" =find just write: "bilbana" this is slotcar track in swedish.

Julius
 

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Julius Wilkko
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935 Posts
Discussion Starter · #19 ·
Porsche seems to be Art n:eek: 45-353. Apparenly they have a web-shop but I don't know whether they deliver outside nordic countries or not.

Julius
 

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Do you realise what you have started here


Inte dosn`t need to worry about the `Old Bill` it`s the Inquisition that are after Witches!


so who will be the first to make a £4 car competitive then
 
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