Low Voltage (Toys, Models and Novelties) Directive 2016

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The Low Voltage (Toys, Models and Novelties) Directive (also known as 16/0401/EC) is the next step towards unification of electrical safety legislation across the EU, and we expect the directive will be ratified later today. This directive is especially relative to railway modellers because it restricts the permitted voltage of exposed electrical conductors such as track to 8.5 volts DC or the equivalent AC value. Analogue motors designed for 12 volts will now reach only two-thirds of their maximum speed, and this revision is clearly far-reaching for many modellers.

 

This paper describes the suggested workarounds for traditional analogue systems and popular DCC systems. We expect Marklin to announce a dedicated solution for their system shortly. We will describe the implications for analogue systems today, then DCC in the weeks to come.

 

Micro Layouts

Owners and operators of micro layouts, shunting planks and similar small systems are almost untouched by the new directive. The lower track voltage will have no visible effect on train operations and will reduce accident damage following heavy-handed operation.

 

A certified zener diode assembly will be available for all existing DC controllers to restrict their output to the mandatory 8.5 volts. A bare-bones component kit will be available for experienced modellers, and we are expecting Peco to supply the diode ready-wired to a pair of leads with crocodile clips for easy installation by beginners and people averse to soldering. All kits will of course be lead-free and certified RoHS-complaint for distribution and use across the EU.

 

Continuous and Main-Line Layouts

Operators of continuous and main-line layouts will need to modify express locomotives and multiple-unit trains to let them achieve better than a scale 85-90 mph. The recommended approach is a fit-and-forget DC-DC convertor module, available as a kit from major stockist. The module fits into any DCC decoder socket in place of the existing header plug, without needing any further modification of the model. The approved “smart 2016” convertor gets its name from a clever non-linear motor drive characteristic, maintaining delicate low-speed control whilst giving a proportionally larger speed increase about and above a scale 90 mph. Built-in back-emf detection circuits handle reasonable main-line gradients up to about 1:40 to maintain a reasonable visible performance from the lower track voltage.

 

Special Cases

1. Advance Passenger Train

We are hoping to begin a detailed discussion with Rapido Trains to facilitate the retro-fitting of a high power DC-DC converter to their APT-E train. This will allow the train to reach a scale 155 mph from the limited 8.5 volt track.

 

2. Pendolino Sets

There are special problems with N-gauge Pendolino sets, where a purely electronic solution can achieve no more than a scale 125 mph, and mechanical re-gearing is impractical. We have tried to contact the procurer of the prototype, but the reply was remarkably curt: “we bought 140 mph trains for 140 mph signalling - and now the hobbyists can feel our frustrations too”. We will try to continue this discussion on a better day.

 

3. Eurostar and TGV Trains

We are expecting all Eurostar and TUV models (00 and H0 scales) to be handled by Hornby International, but unfortunately we have not had any correspondence with the appropriate department here.

 

Forum-based Help and Other Information

The decision to convert and upgrade is straightforward for most models, but a dedicated forum will be set up for borderline cases like analogue users of class 170 DMUs and some class 47 locomotives where emotional as well as technical support will be available to undecided modellers. Specialised advisors will offer recommendations and counselling for modellers of British main-line routes with large numbers of permanent speed restrictions and steep gradients. Advice will of course be free of charge, and indeed available through private messages (PM) for more sensitive members.

 

We expect the directive will be ratified later today, and we hope to publish an update this afternoon, 1 April 2016.

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No replies … I posted this a day early, which was an “oh no” moment, but I guess it was all a bit too convoluted - sorry. I spend too much of my days with the outputs from the EU and IEC and the like …

 

A long time ago I built up a panel-mounted controller into a box with a nominal 12V transformer. It still works beautifully, but I forgot about my design decisions for my current layout.

 

The layout has been running from a “16V AC” transformer of a type widely sold for model railway applications. Having a small layout, this provided plenty of power to run a train, some stall motors for points, a rolling road, and some LED lighting. Small layout, simple power supply, simplicity. I used some linear voltage regulators for the stall motor supplies and set them to give me around 10V DC output - low enough to give a nice slow action, high enough to hold the blades in place. Perfect.

 

The trouble was, these voltage regulators were getting very hot indeed. I fitted some clip-on heat sinks during the build but they would still take my skin off. I would run the layout for an hour or so at a time, but never leave it unattended. Eventually I put a voltmeter onto the input to the regulators (after the rectifiers) and realised the transformer was putting out just over 22V (!). So the regulators were dropping 12V each, and drawing half an amp left them dissipating 6W each. With their tiny heat sinks, no wonder they were jolly hot.

 

I bit the bullet and ordered up a 9V transformer. Probably not enough to run a train, but the numbers said I could make these regulators a lot more efficient. I swapped the transformer in, got myself 13V instead of 22V into the regulators, tweaked the regulator outputs to give me 10.5 out, and soak-tested the power supplies overnight. And now, if I touch the heat sinks, they are barely lukewarm.

 

Finally I tried running some trains. The analogue controller I have is specified to run from 16V AC and only manages to put 7V onto the track, but all of my trains manage to move, and all but one manages to go fast enough to look reasonable on my little end to end layout. If I bought a 12V transformer and tweaked up the regulator outputs (to minimise their voltage drop) I could have faster trains at the expense of faster point blades. Good enough for any application, except perhaps an APT-E.

 

On my last layout with point motors I used solenoid motors driven from a capacitor discharge unit, I ran this unit from a 24V AC supply, and it worked well. Better than it would from 16V AC, especially for the old H&M motors.

 

Now (to get to the point) … I can get 24V AC across two 12V windings … I can run trains and stall motors and lighting from 12V windings … so why are the trade still selling us 16V AC transformers for general model railway use?

 

8.5V is simply the rms value of a 12V p-p AC waveform - sorry. All the other AC values I have quoted are rms.

 

- Richard.