The quote of mine above is several months old when I understood this to be the myth as it related to DCC and things have moved on.
From another topic where this discussion spilt over.
QUOTE You just don't get it, do you? You don't have the first idea what causes Electro magnetic interference, what measures are taken to combat it and what a consumer's duty is once he has a piece of equipment. Neither do you want to know or understand that fitting a decoder fundamentally alters the electrical circuit which may give rise to the interference in the first place. The potentially interfering circuit for which the counter measures were fitted no longer exists.
Or perhaps I have misunderstood you because you are being too circumspect in your target. From your posts I take it that Bachmann, Lenz, ESU and a host of others are in your eyes "breaking the law". Is this correct? If it is not correct, perhaps you would correct me by stating explicitly who you do mean. It would also help me if you would provide a reference to the statute and section number you believe is being violated because I am convinced that you are mistaken. An individual is still innocent until proven guilty in the UK, or least I thought that was the case.
From the ZTC
website:-
QUOTE Q: Should I remove the EMC suppression components from my Locomotives?
A: We NEVER recommend the removal of the suppression circuitry.
First, it is illegal for us, or for that matter any other manufacturer to recommend the removal of a third parties EMS suppression devices. These components are fitted to ensure that the products do not interfere with TV`s and the like, which causes a nuisance and inconvenience. However this also includes some much more important items such as Pace Makers which are life critical.
Secondly, all of ZTC`s Decoders are designed to work with these components installed, as we believe are those produced by other manufactures, but only they can confirm this.
Thirdly, These components are also a necessary requirement to enable the various locomotive manufactures to obtain the obligatory EMC approvals. This testing permits them to print a CE mark on their products, which is also a legal requirement for all electrical equipment sold throughout the European Community.
In an effort to try and clarify this recurring confusion, ZTC Controls Ltd. formally tabled the question at the NMRA DCC working Group (of which other DCC manufactures and we are members) in September 2004 in Salzburg.
The question was "Does any manufacturer of DCC decoders recommend the removal of the locomotive suppression components when fitting a decoder in to a locomotive".
There were 30+ members present and not one said that they would, or do recommended their removal. The working group then minuted this fact.
This information was picked up, and later published on the Yahoo DCC web site by a qualified EMC Engineer, but the myth still seams to prevail that they should be removed.
Incidentally tests conducted by ZTC engineers indicate that many decoders properly installed, from a variety of manufactures including ourselves often do not work as well with these components removed.
ZTC as manufacturers will have the answer you seek so why not pop them an email and see if they answer?
They may be unhappy that the statement they have made and the information relating to their question and answer put to the NMRA commitee has been regarded as spin!
It is my understanding that privately Hornby have a similar interpretation of the law and no doubt there are discussions with the NMRA behind the scenes. As ZTC have already gone public with their interpretation they are in a better position to provide your answer.
Lenz decoders do function perfectly well with EMC devices in place and no doubt those of other manufcaturers mentioned in your list do to.
In another forum member Gordon H said
this:-
QUOTE Sorry, but this second sentence is utter nonsense!
What has the power source got to do with it when the aim of the capacitor is to suppress motor brush arcing and the RF interference it causes? This occurs regardless of control method.
To be effective in its task, such a capacitor needs to be mounted as close as possible to the motor brushes to minimise the current path of the RF interference signal they produce. This usually means directly mounting on the brush terminals. Removing the motor capacitor and relying on the effect of the decoder output stage to do it for you does not give the same level of suppression, as the decoder wires themselves can act as transmitting aerials.
The whole point here is whether a particular decoder is designed to be able to drive a small capacitive load or not. Lots of factors are involved in this, such as PWM rate, motor inductance, capacitor value etc. Each case has to be assessed on its own merits. Also bear in mind that removal of any suppression components may cause the loco to no longer conform to EMC regulations which the manufacturer must adhere to when designing their products these days.
I may be right or wrong but I do believe Gordon H is a member of MERG.
LizaP4 said this in another forum when discussing why Digitrax and Lenz have different instructions. Note the Lenz instruction that Richard Johnson was reading from may have been an Australian version. Digitrax do request CE EMC device
removal:-
QUOTE the rules are a little differant in the EU compared to the US, if Lenz or ZTC or any european manufacturer were to include instructions to remove a suppression device they'd probably get either a massive fine or shut down.
Hence the differance between the ZTC and Digitrax instructions.
Most DCC experts know LisaP4!
Gordon H also said
this:-
QUOTE Pill-46 wrote:
With respect although the manuafacturer may need to comply with EMC regulations I do not, provided I'm not causing a problem.
Try telling that to the man from the DTI if he knocks on your door. How can you know you are not causing a problem to someone else?
Quote:
There are quite a few models in the Bachamnn range which have no Supression devices and I don't think they have ever caused problems.
No reported problems, perhaps, but that doesn't mean they will be immune from the 'EMC police' if they choose to act.
Quote:
There's a considerable difference in size between the motor in a tumble dryer and a small model can motor. However it is a known fact that certain decoders react badly to supression devices, and run far better without.
That's why I said each combination of decoder, motor, and suppression components must be assessed separately. Unfortunately there is no 'one size fits all' solution to this issue.
Quote:
With the capacitor in place they can interfer with 2 areas of decoder function: motor drive, PWM, and BEMF. The decoder may not be able to supply optimum power settings to the motor. The loco's starting and low speed performance will be effected, and overal control will suffer.
Exactly the point I was making - the combination of components, their values, and how they are used has to be engineered to suit each case
Quote:
The decoder it's self does offer a reduction in motor footprint IE elctrical interferance.
To some extent, by the action of the diodes which are inherent to the MOSFET output stages. However, they are in the wrong place relative to the motor brushes themselves, i.e. there is a length of wire in between.
Quote:
Having run a large DCC layout for many years within a short range of TV's and radio's removal of the capcitors and chokes has no effect on applicances, but a large improvement in operation performance can be had by their removal.
Or by re-engineering their arrangement and values to suit a typical representative decoder output stage.
My interpretation of what Gordon H is saying is that when fitting a decoder and unless it is a specific design of decoder for a specific model designed to provide a perfect match with its characteristics and CE EMC, under all other circumstances if you remove a CE EMC device fitted to a loco then you will suffer reduced CE EMC performance.
And then be at risk of a visit from the DTI police!
With the Mattel China situation right now then the last thing Hornby and Bachmann and others will want is a visit from the DTI police!
Happy modelling
Gary
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