DCC Beginner

[RWBKing]

Dear all,

 

Please show a bit of mercy in the level of descriptions as I do struggle with the concept of electrical contacts and flows….I can design and implement an all encompassing and integrated business computer system in a multi-national company…..

 

….but I can't work out how best to connect up my new DCC Elite controller.

 

I've designed the layout and I've even converted my first DCC ready locomotive….next will be to convert a non-DCC ready locomotive - which should be fun….bur first things first! 

 

My first questions are around having multiple circuits and sidings as I have 3 track all within each other and all connected via points, inside of this I have a multi-pointed set of sidings for shunting etc. and on the outside line I have two further sidings -

 

1. How do I connect everything up so that the one DCC controller/power source functions all the way round?

I've realised I need to get the special contacts to convert all of my points….but will these points converters resolve any of the current issues have with losing power in certain places on the laid out test circuit?

 

Is it better to connect up additional circuit to circuit connectors to provide a more direct linkage or leave it to the points connectors to remove the isolation problem?

 

 

2. How do I motorise my points with control from my DCC Controller

I know I'm being a bit dim here but I can see all the different types of electric points but how do I link these to the DCC controller please?

 

 

Any help for a novice very welcome as I have two young lads waiting for the magic touch….where's Harry Potter when you need him!?

 

Many thanks all

[Phil S]

'Special Contacts' are not required for the points - they simply form an easy, off-the-shelf solution to de-isolating the tracks connected to the points.

'All that is required' is for all the 'previous analogue sections' to be connected together .... ie back to the elite main track output.

You don't actually mention which make, or makes, of pointwork you are using: With Fleischmann Profitrack, for example, these 'de-isolating clips' are supplied pre-fittred as standard - and are only removed by the use, if they want point-sleected isolation.

Assuming you have Hornby Pointwork - then the clips are a simple and quick method of de-isolating, but if you are happy using a soldering iron, then they are unneccessary.

 

Some more basics about 'dcc wiring':  In basic theory, there is no need for any isolation, except for reverse-loops,  and 'bridge-sections linking analogue or other digital systems including special 'braking sections', and your Elite ... ... all of which we can probably ignore for now!

 

1/ Stop thinking 'analogue' and its need for isolatable sections to allow individual movement of locos.

2/ Start thinking, that like a House's Ring Main circuit (UK),  you desire to ensure that (the same) electricity (ie the dcc signal from the Elite) reaches ALL parts of the track at ALL TIMES.

 

3/ IF and only if, you have a 'very large layout' .... with a large number of current consuming locos on it at the same time, such that a single elite's output was insufficient, then 'Boosters' would be required, which have identical COPIES of the Master DCC signal, and THESE AREAs need to be electrically separated from each other.

Note that physical size is not the real criteria here, but total current consumption (locos, track powered devices etc) compared to the output of your controller.

 

For example, modern locos each take about 0.25-05A each when running, and an LED lit coach maybe 10-40mA.  An Elite has 4A output capability with the larger power supply

My loft layout is divided into 4 'Power Districts', each capable of supplying nearly 4 amps each, at the same time [ie a 4 Amp MASTER, and 3 more 4 Amp Boosters .... mine are actually Roco ]

However, most of the time, the current being taken in any of the 4 power districts is less than 0.5A ... but adding coach lighting and sound locos has increased this to over 1 Amp at times.

SOME 'starter DCC controllers' only have a 1-2Amp output, and these will 'need' the use of a Booster at an earlier stage.

 

4/ Thinking about your DCC Controlled Pointwork: The DCC CURRENT demand varies considerably between makes of both point motor and accessory decoder....

The 'conventional' ('historical') assumption is the use of an ACCESSORY DECODER to decode the DCC signal, and control 4 locally-connected points using their existing 'analogue' motors.

Typically this has 4 pairs of outputs. SOME (including the Hornby POINT decoder) have an inbult CDU, and take their power from the track, slowly, others usng track power can take 3A or more.

 

I use a mixture of Lenz LS150 6-output Accessory decoders; this NEEDS 16vac for point power, and therefore does not add demand to the dcc supply, but the  4-ouptut ESU/Bachmann SwitchPilot CAN be track powered, or from dc or ac... the latter being more usual .   

Because I use Roco points, I also use Roco Point motors: some analogue (via the decoders above) and others are DIGITAL: ie self-contained and dcc powered (but less than 1A each.)

 

5/ Think about Fault-finding: Faults DO happen occasionally:  With household wiring, the fuseboard separates Lighting, Power Sockets, Cookers, Showers etc

    In the same way, LAYOUT WIRING can be divided logically into TRACK and ACCESSORIES (including DCC pointwork), so that a derailment (track) does not stop points being controlled (accessories).

The larger the layout (physically), the better it is to sub-divide it into more 'areas' [NMRA terminology = Sub-Districts], and I believe in doing this 'geographically' ie 'board by board' or 'route by route' or other logical aid to grouping - and this has NOTHING TO DO with 'Analogue' sections ... although, in converting a layout, many people would simply use (ie retain) these because the wiring and section breaks already exist.

 

6/ AND 'FINALLY' think about SHORT CIRCUITS: What happens when these occur ? How much current flows ? How is you layout or controller protected ? ... SHORTS WILL OCCUR....

SOME OF THE ANSWERS TO THIS depend on your chosen controller, and its current capability !!   IN ANALOGUE this was probably about 1A maximum normal current, and cutout at maybe 2A.

With a  'low current' DCC controller - with only 1-2Amp MAXIMUM normal current capability, the SHORT CIRCUIT CURRENT will only be 2-3Amps BUT with a 4 Amp NORMAL MAXIMUM controller, such as theRoco Amplifier or Hornby Elite, the SHORT CIRCUIT CURRENT will be MORE THAN 4A  before protection circuits will operate ... the CAPACITY OF THE WIRING used NEEDS to take account of this !!

Those who 'reuse' their 'analogue wiring' which was probably designed for 1A per section (ie 1 loco per section) MIGHT MELT if  FOUR AMPS was to be continuously taken ( which is a VALID current for an ELITE ), BUT on the other hand, that wiring might be so thin, that it has so much resisitance that 4 A could not flow, and therefore the 'FAULT CURRENT' would NEVER be reached..

and no protection will be experienced!

To put it another way: the WIRING used should be ADEQUATE for the NORMAL (NON FAULT) MAXIMUM current to flow without any appreciable voltage loss at the furthest part, AND IT NEEDS TO HAVE LOW ENOUGH RESISTANCE so that WHEN A SHORT OCCURS, enough current DOES flow, that the Over-Current Protection CIrcuit in the Controller operates and CUTS the POWER!

 

The LARGER THE LAYOUT, AND THE HIGHER THE CONTROLLER NORMAL MAXIMUM Current, the thicker the wiring needs to be.

The 'Coin Test' - in which a COIN is placed across the track, MUST make the PROTECTION CIRCUIT operate..... or the wiring has too much resistance.

[HLT 0109]

You ask how to connect your Elite - there are red and black clamp connectors from the AC circuit from which you need a wire to each rail on a piece of track; ie a red wire from the red clamp to one rail and a black one to the other rail.  Thus you have power to your track.  Traditionally, the power is passed to the next piece of rail by the fishplates or rail joiners, which is fine whilst they are new and a tight fit but once they get dirty, you lose power.  So it is good practice to bypass the rail joiners by soldering wires "droppers" to the bottom (or outsides) of each rail on each piece of track and connect it to the same side rail on the next piece of track.  That is one way; the other is to run a "power bus" underneath the baseboard and connect the droppers to the appropriate wire of the power bus.  You do that for the points also.  That ensures that all your track is powered.  As Phil has suggested, the point clips to which I think you refer in your paragraph numbered 1 are unnecessary if you are prepared to rely upon the contact between the switch rail and the stock rail to conduct the current but, as those also get dirty it is much better, before laying the points, to solder a small wire to the bottom of the stock rail and the bottom of the switch rail (at a spot that is fixed).  In theory, good rail joiners, and point clips do the job of the power bus and the droppers but experience tells us otherwise.  The power bus and droppers need to be quite chunky - I use 2.5mm sq for the power bus and 1.00mm sq for each dropper.  I used to use the point clips but found them to be a nightmare; like the fishplates, the get dirty and fail to do their job; I have had them glow red hot too!  I have also had them cause derailments as they get dislodged.

 

Expanding on Phil's point number 4, the accessory decoder (eg Hornby's R8247) can be fed from any place on the power bus so the wires can be quite short - they do not need to go back directly to the Elite.  There are then finer wires from the decoder to each point motor.  Each outlet on the decoder is given an address (much like the locomotives) and is called up on the Elite when you want to change the point from which that outlet is fed.

 

I hope, between Phil and me, we have given you helpful information.

 

Harold.

[RWBKing]

'Special Contacts' are not required for the points - they simply form an easy, off-the-shelf solution to de-isolating the tracks connected to the points.

'All that is required' is for all the 'previous analogue sections' to be connected together .... ie back to the elite main track output.

You don't actually mention which make, or makes, of pointwork you are using: With Fleischmann Profitrack, for example, these 'de-isolating clips' are supplied pre-fittred as standard - and are only removed by the use, if they want point-sleected isolation.

Assuming you have Hornby Pointwork - then the clips are a simple and quick method of de-isolating, but if you are happy using a soldering iron, then they are unneccessary.

 

Some more basics about 'dcc wiring':  In basic theory, there is no need for any isolation, except for reverse-loops,  and 'bridge-sections linking analogue or other digital systems including special 'braking sections', and your Elite ... ... all of which we can probably ignore for now!

 

1/ Stop thinking 'analogue' and its need for isolatable sections to allow individual movement of locos.

2/ Start thinking, that like a House's Ring Main circuit (UK),  you desire to ensure that (the same) electricity (ie the dcc signal from the Elite) reaches ALL parts of the track at ALL TIMES.

 

3/ IF and only if, you have a 'very large layout' .... with a large number of current consuming locos on it at the same time, such that a single elite's output was insufficient, then 'Boosters' would be required, which have identical COPIES of the Master DCC signal, and THESE AREAs need to be electrically separated from each other.

Note that physical size is not the real criteria here, but total current consumption (locos, track powered devices etc) compared to the output of your controller.

 

For example, modern locos each take about 0.25-05A each when running, and an LED lit coach maybe 10-40mA.  An Elite has 4A output capability with the larger power supply

My loft layout is divided into 4 'Power Districts', each capable of supplying nearly 4 amps each, at the same time [ie a 4 Amp MASTER, and 3 more 4 Amp Boosters .... mine are actually Roco ]

However, most of the time, the current being taken in any of the 4 power districts is less than 0.5A ... but adding coach lighting and sound locos has increased this to over 1 Amp at times.

SOME 'starter DCC controllers' only have a 1-2Amp output, and these will 'need' the use of a Booster at an earlier stage.

 

4/ Thinking about your DCC Controlled Pointwork: The DCC CURRENT demand varies considerably between makes of both point motor and accessory decoder....

The 'conventional' ('historical') assumption is the use of an ACCESSORY DECODER to decode the DCC signal, and control 4 locally-connected points using their existing 'analogue' motors.

Typically this has 4 pairs of outputs. SOME (including the Hornby POINT decoder) have an inbult CDU, and take their power from the track, slowly, others usng track power can take 3A or more.

 

I use a mixture of Lenz LS150 6-output Accessory decoders; this NEEDS 16vac for point power, and therefore does not add demand to the dcc supply, but the  4-ouptut ESU/Bachmann SwitchPilot CAN be track powered, or from dc or ac... the latter being more usual .   

Because I use Roco points, I also use Roco Point motors: some analogue (via the decoders above) and others are DIGITAL: ie self-contained and dcc powered (but less than 1A each.)

 

5/ Think about Fault-finding: Faults DO happen occasionally:  With household wiring, the fuseboard separates Lighting, Power Sockets, Cookers, Showers etc

    In the same way, LAYOUT WIRING can be divided logically into TRACK and ACCESSORIES (including DCC pointwork), so that a derailment (track) does not stop points being controlled (accessories).

The larger the layout (physically), the better it is to sub-divide it into more 'areas' [NMRA terminology = Sub-Districts], and I believe in doing this 'geographically' ie 'board by board' or 'route by route' or other logical aid to grouping - and this has NOTHING TO DO with 'Analogue' sections ... although, in converting a layout, many people would simply use (ie retain) these because the wiring and section breaks already exist.

 

6/ AND 'FINALLY' think about SHORT CIRCUITS: What happens when these occur ? How much current flows ? How is you layout or controller protected ? ... SHORTS WILL OCCUR....

SOME OF THE ANSWERS TO THIS depend on your chosen controller, and its current capability !!   IN ANALOGUE this was probably about 1A maximum normal current, and cutout at maybe 2A.

With a  'low current' DCC controller - with only 1-2Amp MAXIMUM normal current capability, the SHORT CIRCUIT CURRENT will only be 2-3Amps BUT with a 4 Amp NORMAL MAXIMUM controller, such as theRoco Amplifier or Hornby Elite, the SHORT CIRCUIT CURRENT will be MORE THAN 4A  before protection circuits will operate ... the CAPACITY OF THE WIRING used NEEDS to take account of this !!

Those who 'reuse' their 'analogue wiring' which was probably designed for 1A per section (ie 1 loco per section) MIGHT MELT if  FOUR AMPS was to be continuously taken ( which is a VALID current for an ELITE ), BUT on the other hand, that wiring might be so thin, that it has so much resisitance that 4 A could not flow, and therefore the 'FAULT CURRENT' would NEVER be reached..

and no protection will be experienced!

To put it another way: the WIRING used should be ADEQUATE for the NORMAL (NON FAULT) MAXIMUM current to flow without any appreciable voltage loss at the furthest part, AND IT NEEDS TO HAVE LOW ENOUGH RESISTANCE so that WHEN A SHORT OCCURS, enough current DOES flow, that the Over-Current Protection CIrcuit in the Controller operates and CUTS the POWER!

 

The LARGER THE LAYOUT, AND THE HIGHER THE CONTROLLER NORMAL MAXIMUM Current, the thicker the wiring needs to be.

The 'Coin Test' - in which a COIN is placed across the track, MUST make the PROTECTION CIRCUIT operate..... or the wiring has too much resistance.

WOW!!….Thank you….think I need to re-read carefully - as mentioned my electrical skills are slightly naive / close to stupid at times (a frustrated electrical engineer as a father during my school days and since!)…hope he can help me now.

 

I bought my track largely second hand although some has come out of well worn Hornby boxed sets…am sure they are all isolated.

 

Thanks you so much for taking time out to respond and I'm sure it will all prove to be very useful.

 

Kind regards,

 

Ian.

[RWBKing]

You ask how to connect your Elite - there are red and black clamp connectors from the AC circuit from which you need a wire to each rail on a piece of track; ie a red wire from the red clamp to one rail and a black one to the other rail.  Thus you have power to your track.  Traditionally, the power is passed to the next piece of rail by the fishplates or rail joiners, which is fine whilst they are new and a tight fit but once they get dirty, you lose power.  So it is good practice to bypass the rail joiners by soldering wires "droppers" to the bottom (or outsides) of each rail on each piece of track and connect it to the same side rail on the next piece of track.  That is one way; the other is to run a "power bus" underneath the baseboard and connect the droppers to the appropriate wire of the power bus.  You do that for the points also.  That ensures that all your track is powered.  As Phil has suggested, the point clips to which I think you refer in your paragraph numbered 1 are unnecessary if you are prepared to rely upon the contact between the switch rail and the stock rail to conduct the current but, as those also get dirty it is much better, before laying the points, to solder a small wire to the bottom of the stock rail and the bottom of the switch rail (at a spot that is fixed).  In theory, good rail joiners, and point clips do the job of the power bus and the droppers but experience tells us otherwise.  The power bus and droppers need to be quite chunky - I use 2.5mm sq for the power bus and 1.00mm sq for each dropper.  I used to use the point clips but found them to be a nightmare; like the fishplates, the get dirty and fail to do their job; I have had them glow red hot too!  I have also had them cause derailments as they get dislodged.

 

Expanding on Phil's point number 4, the accessory decoder (eg Hornby's R8247) can be fed from any place on the power bus so the wires can be quite short - they do not need to go back directly to the Elite.  There are then finer wires from the decoder to each point motor.  Each outlet on the decoder is given an address (much like the locomotives) and is called up on the Elite when you want to change the point from which that outlet is fed.

 

I hope, between Phil and me, we have given you helpful information.

 

Harold.

Hi Harold, Many thanks for your time and efforts to respond, this has been extremely useful and would also extend my thanks to explaining things at my level of understanding.

 

I'm sure this will frustrate you but I'm a bit unsure by the sentence…and yes I really am that dim!….especially for a business systems implementation consultant! :-)

'run a "power bus" underneath the baseboard and connect the droppers to the appropriate wire of the power bus.'

1) I'm unsure what you mean by a power bus (is this purely a wire circuit under the base board which then connects to the Elite controller?

2) If it is, is a dropper soldered from this circuit to the track through a hole in the base board

 

My father would be slapping his forehead and groaning at me by this point - I'm hoping I can ensure my sons are less ignorant than I - and what better way than to all learn together! :-)

 

I just hope we don't blow the whole thing up…..on a separate note and older train seemed to blow it's motor, rather telling smell and smoke as it was trying to reverse, is there a simple way to test the motor?

 

Many thanks again for your time and efforts to educate and to help, I'll hopefully post a picture of my efforts and a progress report at some point.

 

Kind regards,

 

Ian.

[Tricky Dicky]

Ian

 

You are correct about what a power bus is and that the droppers are the connections between the bus and the rail. Be aware the power bus needs to quite hefty wire as it carries the total current consumed by your layout but more importantly does not cause a voltage drop at the extremes. The droppers can be thinner wire as long as they are not long. Brian Lambert's site has a good graphical explanation of a typical power bus in the DCC section.

 

http://www.brian-lambert.co.uk/DCC.html#Comparison

 

Richard

[RWBKing]

Ian

 

You are correct about what a power bus is and that the droppers are the connections between the bus and the rail. Be aware the power bus needs to quite hefty wire as it carries the total current consumed by your layout but more importantly does not cause a voltage drop at the extremes. The droppers can be thinner wire as long as they are not long. Brian Lambert's site has a good graphical explanation of a typical power bus in the DCC section.

 

http://www.brian-lambert.co.uk/DCC.html#Comparison

 

Richard

Many thanks Richard…..I'm feeling a tad more confident about the next steps thanks to you all.

 

Kind regards,

 

Ian. 

[HLT 0109]

Ian,

 

Richard has beaten me to it.  I sense that you are happy with a soldering iron, and soldered joints are generally the best but I made my power bus in 2' lengths joined by terminal blocks with screws which gave me places to attach the droppers from the rails.  I soldered the droppers to the bottom of the rails after removing the webbing between two sleepers, then the wires pass through a single hole in the baseboard, positioned in the 4ft (ie between the rails).  The screws in the terminal blocks can become loose after a while and may need to be checked and tightened - I found this after about a year but, having tightened them once, they appear to be still OK after a further four years.

 

Regarding the train smoke - that is rather worrying and I don't know what to suggest.  If other locos still run, it suggests a problem with the loco rather than the track; it could be a short within the loco wiring or motor, or it could be that the there is too much friction in the drive somewhere causing an overload for the motor.

 

Good Luck!

Harold.

[RWBKing]

Ian,

 

Richard has beaten me to it.  I sense that you are happy with a soldering iron, and soldered joints are generally the best but I made my power bus in 2' lengths joined by terminal blocks with screws which gave me places to attach the droppers from the rails.  I soldered the droppers to the bottom of the rails after removing the webbing between two sleepers, then the wires pass through a single hole in the baseboard, positioned in the 4ft (ie between the rails).  The screws in the terminal blocks can become loose after a while and may need to be checked and tightened - I found this after about a year but, having tightened them once, they appear to be still OK after a further four years.

 

Regarding the train smoke - that is rather worrying and I don't know what to suggest.  If other locos still run, it suggests a problem with the loco rather than the track; it could be a short within the loco wiring or motor, or it could be that the there is too much friction in the drive somewhere causing an overload for the motor.

 

Good Luck!

Harold.

Many thanks again Harold - Greatly appreciated and yep ready to do battle with the soldering iron that was one thing I learnt from Dad at an earlyish age…probably somewhat out of practice 35yrs later though! :-)

 

Kind regards again to all and will feed back on progress at some point - this has all been a great help.

[BR60103]

Ian:

the smoke could be the DCC chip, too.  One chipping consideration is that the input side (to the wheels) has to be isolated from the output side (to the motor).  Lots of older locos are not made this way. 

I talked to Herr Lenz a dozen years ago and he said that there was a 3-wire chip on the way to handle this -- I haven't heard any more.