Track Snubber

[Fazy]

I've been told I might need to build a Track Snubbber. 

 

Below is the question I asked.

 I am having trouble with one or the other. I am building a layout and having fitted the frist six points motors . I am currently testing the layout before moving on to anymore building.

 

The point motors are feed of the track busbar.

 

I managed to get the frist 4 fully working. A couple of days later I weird up the next two which worked fine but the frist 4 would not work. After much testing nothing seemed wrong I reset them long story short all six worked fine.

 

Come to day none are working. I haven't reset them yet.  I ran a couple of loco's but one did not respond  to its ID and needed to be re-a dressed.  

 

now if i know correctly the id is kept on the dcc chip or point motor in this case. So the question is have i got six faulty point motors or is the controller going wrong 

 

Can someone please in lighten me.

[Chrissaf]

The point motors are fed off the track busbar.

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As written, this infers that you are operating the point motors as manually operated point motors via electrical switches, but using DCC track power as the power supply source.

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If this inference is incorrect, can you please clarify exactly how you are powering the point motors?

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I would like to assume that you are using the DCC track power to connect initially to 'DCC Accessory Decoders'. If so what brand / model?

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What brand / model of point motors are you using?

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If you are indeed using DCC track power to manually operate point motors via manual switches as you have inferred, then it is no wonder that you are experiencing other DCC issues. DCC track power is not designed for that task. If you are going to operate the points manually and not via DCC commands, then you must use an appropriate separate power supply [preferably via a CDU for Solenoid based point motors] to power them.

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Or is it that the vital bit of information that you failed to put in the post, is that you are using DCC Concepts iP Digital point motors that have their own integrated Accessory Decoders. You must remember that we are not familiar with your layout build and have to rely totally on what you write in your post.

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If you are using iP Digitals. Then what DCC Controller are you using?

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There are loads of posts on here regarding iP Digitals that just seem to stop working and lose their configurations for no logical reason and that these affected decoders seem to be near impossible to reset and recover. Resulting in getting replacements from DCC Concepts under their 'No Quibble Warranty'.

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You mention a 'Snubber' - fitting one would normally be advised if and when decoders start to lose their configurations after a transient track short circuit. Snubber theory can be viewed here:

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PS - Operational DCC Address IDs are stored in the decoders.....nowhere else. In the case of DCC Concepts iP Digitals.....the decoder is physically inside the iP Digital point motor case.

 

[Fazy]

Sorry Chrissaf I must have deleted a line by mistake.

The point motors are the  dcc concepts  Colbolt ip motors. these have a dcc chip inside them removing the need for accessories decosees the controller is the Bachmann Dynami. I found some snubbers,  and thinking of making one just trying to find a diagram for on

[Chrissaf]

Here you go......

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I recommend that the 100 Ohm resistor is rated at 2 watts. This resistor will get very warm to the touch (mine do) this is normal. The 0.1uF capacitor is a 'ceramic' disc type and should be rated at 50 volts or better. The thick black lines represent the DCC track bus that connects to the track and the iP Digitals. Substitute the reference to R8247's in the schematic with iP Digitals [this is a previously drawn schematic I am just re-posting].

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I would only fit one snubber, two at absolute most. I do not recommend fitting an individual snubber on a one per iP Digital basis, as too much current will be taken from your controller supply if you do. Each snubber you fit, will draw about 100mA from your DCC controller supply. Hence why they get very warm (hot).

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/media/tinymce_upload/a0d109690547958f6a4dd94449d96ec2.jpg

[Fazy]

Ohh that simple brilliant

 

thank you Chrissaf

[Chrissaf]

Post bumped to bring my later edits to your attention.

[Fazy]

I see I'll let you know how I get on. After reading the link I'll also redo the bus bar.  as the one I did was a temporary one just to get the layout running.   Thank you again Chrissaf

[Fazy]

Maybe a daft question I've ordered what you suggested  disc type which I ordere.   But there's different shapes dose the shape make a differenc?

[Chrissaf]

The shape doesn't really matter. The main thing is the material it is made of and the spec. The brown disc type is one of the most common available, but other manufacturers do make them in other shapes such as square and in different colours such as blue.

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As long as the product spec states that it is a "ceramic" capacitor.

That the value is 0.1uF (0.1 microfarads)

That the voltage rating is 50 volts or better (personally I would go with 100 volts which is another standard rating value for this type of capacitor).

[Nick_]

There are arguments both for and against snubbers. In my opinion unless you are building a really large layout such that your DCC bus is really long (say 20m+) then there is really no need for a snubber. I once installed one on the DCC bus of a 2.8m x 2.8m layout powered by an eLink with a 4A power supply and it actually made things worse!I once had a problem that sounds somewhat similar to yours and it eventually turned out to be a wiring fault so I would really recomend double double checking all your wiring. 

[Fazy]

My layout is 18ft by 10 which is about 18 meters running length 

[Fazy]

/media/tinymce_upload/7922c6aca380f7ecffc7f334c849a1c5.jpg

[Chrissaf]

My own layout is 34 metres (total) of track in a condensed area about 2.5 metres square. I had DCC issues which my 'snubbers' (2) totally resolved. In general, I personally would say that they are a good insurance policy for any layout (regardless of size). This is the very first time I have heard anybody say that a well designed and properly installed 'snubber' made something worse (see post on previous forum page).

[Nick_]

My own layout is 34 metres (total) of track in a condensed area about 2.5 metres square. I had DCC issues which my 'snubbers' (2) totally resolved. In general, I personally would say that they are a good insurance policy for any layout (regardless of size). This is the very first time I have heard anybody say that a well designed and properly installed 'snubber' made something worse (see post on previous forum page).

I eventually found that my problem was being caused by a restive short circuit. This meant that my eLink was supplying over 3A continuously (my eLink has the 4A supply). Adding snubbers simply increased the current draw further! I have discovered that running an eLink at near its maximum continuously can distort the DCC waveforms and thus cause problems. Once the restive short circuit was removed everyting worked perfectly without snubbers. That's why I suggest it is worth double checking the wiring first...

[96RAF]

You obviously have a way of monitoring the eLink waveform.

Any chance you could post a picture of the scope trace so we can see what sort of distortion you are getting.

It would be interesting to test other controllers at heavy load as this is the first time I have heard of the problem.