DCC Loop problem

[Fuzzy49]

Well here go's...

First, I am a new member and new to DCC. I have a Roco z21 White system as a starter set, just to get to know the way DCC works. To me at this point it is very "Confusing". But I am learning as I go.

Now I need to know...I made a sample LOOP track [see picture] and when I move the engine from the main track around the Loop and back onto the main track going the other way the engine reverses and stops. I am using an ATLAS INSULFROG Turnout [without their point motor]. How then do I wire up the Cobalt IP Digital so it can change the polarity when I exit the Loop?

Cobalt Digital IP point motor to the Turnout using a Red and Black wire to connect to the Buss Line to power it, this I got so far. But where do I hook up the Green Frog wire to the Turnout and Cobalt so it can switch the polarity of the track? The turnout has an insulated Frog. Or is there some other way to achieve this?

I was told that for a return loop you would need to use an auto revers-er, connected to the loop this changes the polarity automatically. But what is the best choice and most reasonable for a system?

I don't want to go broke doing this. I will be expanding my layout too. Not quit sure just how big yet.

My old DC system was two 4' x 8' a 3' x 2' a 8' x 2' and a 8' x 6' sections in my basement. I do have it listed on Craigs list, but if I can't get rid of it then I will re-do the whole set up to DCC.

 

[RAF96]

You have what is known as a reverse loop which invokes a short circuit that will trip your controller out.

 

If you say one rail is red and the other is black then trace it round the track as you traverse the loop then back through the points red becomes black and vice-versa.

 

You need a reverse loop module which monitors the DCC track polarity  and automatically swaps it over in the loop.

[newbryford]

 

As per the same question you raised on another forum a couple of days ago - you do not need frog wiring - it is an insulfrog point.

As it says there and as Rob repeats above - you have a reverse loop that requires both rails to be polarity switched.

It is nothing to do with frog polarity/switching.

 

To understand this from your photo  - from the point, follow your "+" rail around the loop - when it comes back - it will now be your "-" rail".

Do the same with your "-" rail around the loop in the same direction. It will become the "+" rail.

Hence the need to reverse the section around the loop as the train travels around it.

 

( I know DCC isn't + and -, but if it helps the OP to recognise his two rails, then let's keep it at that)

 

If you reverse the two wires on a DCC system, the loco will not reverse direction as it does on a DC/analog system. 

The DCC loco simply receives the same command - i.e. forwards is still forwards regardless of which way the DCC is connected to the rails. In simple terms: if you have a loco travelling chimney first, pick it up, turn it around 180 degrees and place back on the track - it will still travel chimney first.

 

Using the likes of a DCC auto-reverser, the polarity change should be fairly seamless and not noticeable

[Nigelcliffe]

following the two posts above, this website may help,  scroll down and there is a diagram of a loop almost exactly like the one in the question.   The maker is one of many offering auto-reversing devices. 

 

http://www.blocksignalling.co.uk/index.php/dcc-autoreverser-rev1

[Suzie]

I am assuming that you are feeding your DCC into the loop. In this case you can use your point motor to do all the reverse switching. There is no need to buy anything else.

1. Fit insulated joiners in the outer rails of the point where it meets the loop. No need for any other insulated joiners.
2. Jumper 1-5 and 2-4 on your Cobalt IP motor.
3. Connect the DCC in from your track to to terminals 1 and 2 (DCC in) of your Cobalt IP Digital motor.
4. Connect terminal 3 (frog) to one rail of the point.
5. Connect terminal 6 to the other rail of your point.

If you are seeing a short when the train crosses the insulated gaps then reverse the wires going to terminals 3 and 6.

 

It is a bit complicated, but follow the steps and you should be OK.

[newbryford]

12 hours ago, Fuzzy49 said:

Well here go's...

First, I am a new member and new to DCC. I have a Roco z21 White system as a starter set, just to get to know the way DCC works. To me at this point it is very "Confusing". But I am learning as I go.

Now I need to know...I made a sample LOOP track [see picture] and when I move the engine from the main track around the Loop and back onto the main track going the other way the engine reverses and stops.

 

 

 

 

 

It looks like your sample loop uses a DC controller to test it - that's why your loco reverses after it goes around the loop.

If it was DCC, it would short out - unless an auto-reverser was used.

[newbryford]

4 hours ago, Suzie said:

I am assuming that you are feeding your DCC into the loop. In this case you can use your point motor to do all the reverse switching. There is no need to buy anything else.

1. Fit insulated joiners in the outer rails of the point where it meets the loop. No need for any other insulated joiners.
2. Jumper 1-5 and 2-4 on your Cobalt IP motor.
3. Connect the DCC in from your track to to terminals 1 and 2 (DCC in) of your Cobalt IP Digital motor.
4. Connect terminal 3 (frog) to one rail of the point.
5. Connect terminal 6 to the other rail of your point.

If you are seeing a short when the train crosses the insulated gaps then reverse the wires going to terminals 3 and 6.

 

It is a bit complicated, but follow the steps and you should be OK.

 

 

Terminals 3 and 6 should be connected to the two rails of the loop beyond the isolated gaps - not the point.

But:

The break before make of the Cobalt will most likely cause the train to stop in the loop - not a problem if Fuzzy is already stopping the train in the loop anyway - or if there is a decent stay alive capacity within the loco.

[Suzie]

I was assuming that the main feed was in the loop judging from where the controller was, but if not...

 

... the wiring will be a lot easier since the inside rail of the loop will be fed from the insulfrog point, only the outer rail will need to be switched with the frog connection, no need to use terminals 3, 4, and 5.

[Fuzzy49]

On 15/03/2020 at 19:17, newbryford said:

 

As per the same question you raised on another forum a couple of days ago - you do not need frog wiring - it is an insulfrog point.

As it says there and as Rob repeats above - you have a reverse loop that requires both rails to be polarity switched.

It is nothing to do with frog polarity/switching.

 

To understand this from your photo  - from the point, follow your "+" rail around the loop - when it comes back - it will now be your "-" rail".

Do the same with your "-" rail around the loop in the same direction. It will become the "+" rail.

Hence the need to reverse the section around the loop as the train travels around it.

 

( I know DCC isn't + and -, but if it helps the OP to recognise his two rails, then let's keep it at that)

 

If you reverse the two wires on a DCC system, the loco will not reverse direction as it does on a DC/analog system. 

The DCC loco simply receives the same command - i.e. forwards is still forwards regardless of which way the DCC is connected to the rails. In simple terms: if you have a loco travelling chimney first, pick it up, turn it around 180 degrees and place back on the track - it will still travel chimney first.

 

Using the likes of a DCC auto-reverser, the polarity change should be fairly seamless and not noticeable

To everyone on my post...

I am so sorry that I never responded back to your answer to my problem.

DCC Loop Problem dated back in March 15, 2020.

I was new to this Forum back then [in fact any Forum] and I'm not sure how to set up to get responses to me in my Email.

I will investigate this and try to fix it so I will receive responses. When next I have a question or a problem.

I think I fixed it, so respond if you would like. I would like to here from you all.

Thank you

Fuzzy49