How do you set up a reverse loop
- Thread starter Mez
- Start date
steve parberry
G Scale Trains
It can be a bit of a challenge!! is it massoth?
The english instructions do not come with the unit but can be downloaded from the massoth web site,,, i have one installed and can do you a picture latter and feel free to ask me any questions.
The english instructions do not come with the unit but can be downloaded from the massoth web site,,, i have one installed and can do you a picture latter and feel free to ask me any questions.
Gizzy
A gentleman, a scholar, and a railway modeller....
This help Mez?
You need 4 isolating joiners which I've marked with yellow dots.
You should have 2 wires going to an input which you connect at the toe end of your point and 2 wires which you can connect anywhere within the loop.
MMTS uses one of these on his loop and it works fine....
You need 4 isolating joiners which I've marked with yellow dots.
You should have 2 wires going to an input which you connect at the toe end of your point and 2 wires which you can connect anywhere within the loop.
MMTS uses one of these on his loop and it works fine....
mmts
Registered
Gizzy said:
Oh yus I have one and it works fine
Digital trains just run over the isolating joiners and continue in the same direction
Analouge trains have to run up to them and change direction
Yellow circles are the isolating joiners and the red one is where the power is fed in,the module also takes power from the main line
Gizzy
A gentleman, a scholar, and a railway modeller....
Now there's a thing?mmts said:Gizzy said:
Oh yus I have one and it works fine
Digital trains just run over the isolating joiners and continue in the same direction
Analouge trains have to run up to them and change direction
Yellow circles are the isolating joiners and the red one is where the power is fed in,the module also takes power from the main line
I didn't realise that these work in Analogue mode too, similar to the LGB 1015 T units that I use on my railway.
You learn something new here every day....
steve parberry
G Scale Trains
Mez said:
Yes Massoth but i have gone for the all singing instalation version with the extra change over switching bit because i will have two and if they detect a short then they flip the current but with the sensor tracks no shorting to activate!! But its optional have mine wired up for my triangle
steve parberry said:Mez said:
Yes Massoth but i have gone for the all singing instalation version with the extra change over switching bit because i will have two and if they detect a short then they flip the current but with the sensor tracks no shorting to activate!! But its optional have mine wired up for my triangle
More considerations.
Will have to do some more thinking.
Cheers
GrahamMills
Many & various. In G scale it is American Diesel.
I have never understood reverse loops and partly as a result have never attempted them.
The bit that always confuses me is that a loco with multiple wheels picking up current must at some stage be bridging the insulated gap and therefore why does it not short.
In DCC land I understand that the direction that a loco travels is independent of the 'flow' of current to the track. Therefore why do you need anything other than one insulated gap? is that where my previous comment about shorting comes into play?
If anyone can explain this in a way that will enable me to understand the underlying principle i would really appreciate it.
The bit that always confuses me is that a loco with multiple wheels picking up current must at some stage be bridging the insulated gap and therefore why does it not short.
In DCC land I understand that the direction that a loco travels is independent of the 'flow' of current to the track. Therefore why do you need anything other than one insulated gap? is that where my previous comment about shorting comes into play?
If anyone can explain this in a way that will enable me to understand the underlying principle i would really appreciate it.
GrahamMills said:
Hi Graham,
I'll have a go....
If you had only one insulated gap on a reverse loop then when the loco runs over that gap, the short would occur as if there was no insulation whatsoever. So some clever bugger decided that the easiest way to avoid the short in DCC land would be to have 2 insulated joint just inside of the loop and a module that takes its power from the main track and provides power to the reversing loop.
This module (a reversing loop module!) switches the polarity of the reversing loop tracks if a short circuit is detected as the train bridges the gap over the insulation. So if a train enters the reversing loop and the causes a short, the polarity is reveresed and the short is no more.
Like wise, if a train enteres the reversing loop and the polarity of the reversing loop is correct, no short will occur but as the train exits the loop a short will occur and the reversing loop will change polarity.
Now, if you have more than one of these reversing loop modules on your layout a short cirbuit will normally trigger all of them to swap polarity.
Newer versions of them allow you to install "detector" rails at the entry and exit of the reversing loop which allow them to detect to correct polarity before the train enters the loop so that they can switch the reversing loop polarity to match without any short circuit.
Hope that helps and that I have not confused you any more than necessary
Neil Robinson
Registered
Deleted as previous reply was posted whilst I was formulating mine.
GrahamMills
Many & various. In G scale it is American Diesel.
Many thanks.
I was understanding well until you got to the 'detector' rails.
Presumably these mean that the loco goes into the loop without a short being created but a short still occurs when the loco exits the loop?
I guess that you can have problems if you have two locos entering/exiting the loop at the same time?
Is the appropriate Massoth component number 8157001?
I was understanding well until you got to the 'detector' rails.
Presumably these mean that the loco goes into the loop without a short being created but a short still occurs when the loco exits the loop?
I guess that you can have problems if you have two locos entering/exiting the loop at the same time?
Is the appropriate Massoth component number 8157001?
That's a very good explanation; but I would not worry about having two loops - one at either end of a "dog bone" for example - each with their own reversing module (LGB 55080 in my case). Unless a train hits one module break (or the corresponding insulated joint) at exactly the same instant as a train hits the other, the two modules will operate independently and a train in the other loop will just carry on. The loop has to be long enough to contain all vehicles which take power from the track. There is no problem with 3 axle locos travelling on over the gaps - my Corpets do it all the time - momentum seems to take them through, and of course the decoder doesn't mind which rail is which and carries on in the same direction...
GrahamMills said:
Yes the Massoth part no is 8157001, the LGB part no is 55080 for the older version or 55081 for the newer one (equivilent to the Massoth one).
Sorry about the "detector" rails. What I should have sais was that they are non powered track (about 1" long) that is placed between the main track and the reversing loop section where the isolation breaks are and thus can be used to detect the polarity on entry and exit of the loop.
GrahamMills said:
Sorry Graham - my last post went up before I read this one. The point is that the loop is independent of the main track power. It is double insulated at one end, and at the other, power goes through the module (I think Massoth 8157001 is LGB 55080 in a blue box). There is a short which ever way a train enters the loop - you can see the amps spike on a Navigator - but this is what triggers the module to reverse the current inside the loop. If a second train enters the loop while the first is still in it, then the current is right. When the first train exits the loop, current will change again. But - see above - this doesn't matter to the second train, which carries on. The only problem is if an exiting train hits the break at exactly the same moment as an entering train hits the other break; the poor module can't cope and everything shuts down. Move one train centimetres either side of the break and restart. Module not hurt at all.
GrahamMills
Many & various. In G scale it is American Diesel.
I must admit that I also worried about the spiking of amps during the short circuit. The control station is expensive enough (whatever make) not to want to damage it by surges. Readiing on the Massoth site I see that they claim their new modules don't do that:-
[BLOCKQUOTE]"Conventional units cause short term, short circuits when the train enters the loop to trigger a change in the polarity of the track voltage.
The new DiMAX Reverse Loop Module avoids just that. The deliberate overload of the Digital Central Station by this method does not exist anymore. The DiMAX Reverse Loop Module extends the lifespan of all components involved considerably."
edit: for spelling again[/BLOCKQUOTE]
[BLOCKQUOTE]"Conventional units cause short term, short circuits when the train enters the loop to trigger a change in the polarity of the track voltage.
The new DiMAX Reverse Loop Module avoids just that. The deliberate overload of the Digital Central Station by this method does not exist anymore. The DiMAX Reverse Loop Module extends the lifespan of all components involved considerably."
edit: for spelling again[/BLOCKQUOTE]