How do you set up a reverse loop

[philkelly]

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]

Ooo, the things they don't tell you when you buy expensive kit. 1200Z has a factory default setting before it shuts off because of a short circuit which (I don't have the manual to hand) is set to allow the short circuit to do its bit with the module without shutting down the 1200Z. So this setting (used in accordance with instructions) is shortening the life of my 1200Z, is it? I wonder how the Massoth module works if it isn't by detecting the short circuit - probably just better electronics detecting it and changing the current more quickly? I am reconfiguring my railway and will need another reversing module. I will get a 8157001 and see if the amps spike...

 

[muns]

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]

Ooo, the things they don't tell you when you buy expensive kit. 1200Z has a factory default setting before it shuts off because of a short circuit which (I don't have the manual to hand) is set to allow the short circuit to do its bit with the module without shutting down the 1200Z. So this setting (used in accordance with instructions) is shortening the life of my 1200Z, is it? I wonder how the Massoth module works if it isn't by detecting the short circuit - probably just better electronics detecting it and changing the current more quickly? I am reconfiguring my railway and will need another reversing module. I will get a 8157001 and see if the amps spike...

The Massoth unit and the LGB 55081 CAN use detector rails, placed in the track at the same place as the isolating gaps that are used by the module to tell it what rail polarity the reversing loop should be so that it can switch it before the train enters the section and thus no short circuit. The same happens when exiting the loop.
They can use short circuit detection as well.

Never managed to get my Massoth unit to work correctly using the detector rails method.

 

[Mez]

Good info.
Keep it coming

 

[muns]

Wiring for the Massoth unit

Detector rails:

 

[philkelly]

The Massoth unit and the LGB 55081 CAN use detector rails, placed in the track at the same place as the isolating gaps that are used by the module to tell it what rail polarity the reversing loop should be so that it can switch it before the train enters the section and thus no short circuit. The same happens when exiting the loop.
They can use short circuit detection as well.

Never managed to get my Massoth unit to work correctly using the detector rails method.

Paul: How are the detector rails wired? 55080 is simple - inner rail to inner, outer to outer, through the module. Do they need to be insulated from both loop and main?

 

[philkelly]

OOps - missed post above; looks excessively complicated...

 

[Mez]

So is that the good ways as in muns post.

 

[korm kormsen]

Graham,

there need no short to be.

the easiest analogue way for a loop is to completely isolate a part of the track in the loop.

from there on you got two possibilities:
manual:
reverse the power, when the loco stops on the dead track - then connect the reversed power with a pushbottom to the dead track.

automatic:
connect the "dead" track with diodes to the power, that it always has the same direction of current, no matter, if the power is in reverse, or not.
place a reedcontact, that the train, while on this part of the track, activates the switch of the loop's turnout.
if you use LGB switches, you just put the addition-switch, that changes the polarity of trackpower.
(needed: 2 loops, two turnouts, two electric switches, one additional switch, two reedcontacts, one magnet per loco)

 

[whatlep]

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]

Graham

The Massoth text is entirely accurate, provided that you use the "detector" feature which has been described earlier. Otherwise, the Massoth unit is as dumb as an LGB 55080 (an earlier and cruder Massoth design badged for LGB).

There is another BIG benefit from using the Massoth kit in "detector" mode, in that you can have multiple reversing loops on a layout which act completely independently of each other. With a 55080, all reversing loops change polarity whenever any requires a polarity change. Not good if you have a trackplan like mine (reversing loops at either end of the run) and want to run two trains freely!

At the risk of giving you brain ache, the Massoth reversing loop module can work in two ways:

1) Short-circuit detection (LGB 55080 look-alike). As others have described, the unit detects if a short-circuit occurs as a train enters or leaves the isolated section of track which forms the reversing loop. The electronic switching is designed to be quicker than the short-circuit trip in the central station. As Massoth make LGB's as well as their own, you may be confident that the design is robust, BUT over time the spike may affect components and certainly will cause some pitting of wheels and track. You can hear the spark happen if you are close to the isolating joints in a quiet area like mine! You can also see loco headlamps flicker for an instant
2) Advance switching of polarity using either "detection tracks" or a reed switch with magnets on the loco. The detection tracks have been described above, but the concept is simple. As a pair of electrically conductive wheels run over the track, they complete a circuit (completely separate from the power to the tracks) and the module knows which way to switch polarity inside the reversing loop before the train crosses the isolating joiners either on the way out or in. No short-circuit ever occurs, so no spark does either, nor do the lights flicker.

There is a small jumper connection inside the Massoth module which you can use to turn off short-circuit detection and I'd receommend that you do so and go for scheme (2).

If you want practical help on this, feel free to PM me or we can talk by phone.

 

[GrahamMills]

Thanks everybody.
The new layout that I recently laid is one where some of the obvious extensions could require a reversing loop which is why I expressed my interest in how it all works.
When I have the money available I will acquire a reversing module and see how we go.
If I have any problems i will get back to you very helpful guys.

 

[whatlep]

Thanks everybody.
The new layout that I recently laid is one where some of the obvious extensions could require a reversing loop which is why I expressed my interest in how it all works.
When I have the money available I will acquire a reversing module and see how we go.
If I have any problems i will get back to you very helpful guys.

Graham

No problem! While you were penning your message, I popped out and photographed one of my reversing loops for a practical example:

Here's a broad view of the loop. You should be able to see the detection tracks in the foreground. The reversing module ideally wants to be as close to the track feeds (main part of layout and reversing loop) as possible to reduce voltage loss, but also needs to be in a water-resistant environment. Mine is in the bird box visible top left of picture. It's about 3 metres away which is farther than I'd like, but it is definitely OK in the bird box, having survived the worst that the 2009-10 winter could throw at it.

This is a closer view of the detection tracks. Note that I only have the two detecting circuits wired in. The power feeds are located elsewhere.

The black box screwed to one track is a reed switch which is an alternative to the detector rails, though this particular one is used for another purpose: it automatically switches the point exiting the reversing loop when triggered by a magnet underneath a passing loco. There is a second reed switch which controls entry to the loop. Another clever feature you get on a Massoth unit (the point module this time) you can't get on an LGB one!

 

[Mez]

Whatlep.
So the pics above are the non shorting version
or number two listed above.post#29

 

[whatlep]

Whatlep.
So the pics above are the non shorting version
or number two listed above.post#29

Yes to both.

 

[stockers]

Thanks Whatlep and all. Seeing as my extension will have a return loop thats all very informative.
Cheers

 

[coyote97]

I know this is not helpful at all:


but seeing this, i remembered some reasons why to go on RC accu-power.


Greetings

Frank

 

[3Valve]

Having just received two reverse loop modules this is all really informative stuff. Just one question Peter (whatlep) if I may?

The wiring of your loop seems different to the piccy provided by Mark (and in the instructions for the unit). Your wiring looks waaay simpler. Just curious as to why the different wiring setup?

Now the general numpty question. What are the diodes for and where to I stick em? (be nice now )

 

[beavercreek]

Hi Gareth
The four diodes are for the sensor tracks (two per segment one for each track.
These are used only if you are using the sensor operation otherwise the the unit will just use the short circuit detection mode.
The diodes are to help 'operation' issues with the sensors and can be left out if everything behaves itself.
I have them on both reverse loops with also the internal jumper set to 'short circuit detection' mode just in case the sensors don't cut it (ie if they were saturated, confused etc).
The diodes should be wired to the sensors and the module as in the piccy from the manual

 

[muns]

Having just received two reverse loop modules this is all really informative stuff. Just one question Peter (whatlep) if I may?

The wiring of your loop seems different to the piccy provided by Mark (and in the instructions for the unit). Your wiring looks waaay simpler. Just curious as to why the different wiring setup?

Now the general numpty question. What are the diodes for and where to I stick em? (be nice now )

The wiring will be the same....the diagram in the manual (and in my post) concentrates all the connections around the detector rails. As Peter says in his post

This is a closer view of the detection tracks. Note that I only have the two detecting circuits wired in. The power feeds are located elsewhere.

Diodes as per the previous post.

 

[steve parberry]

Won't even post a note about how to wire in a triangle with detectionbut if you are interested then drop me a PM lets just say there are more wires than the Massoth diagram

 

[3Valve]

Having just received two reverse loop modules this is all really informative stuff. Just one question Peter (whatlep) if I may?

The wiring of your loop seems different to the piccy provided by Mark (and in the instructions for the unit). Your wiring looks waaay simpler. Just curious as to why the different wiring setup?

Now the general numpty question. What are the diodes for and where to I stick em? (be nice now )

The wiring will be the same....the diagram in the manual (and in my post) concentrates all the connections around the detector rails. As Peter says in his post

This is a closer view of the detection tracks. Note that I only have the two detecting circuits wired in. The power feeds are located elsewhere.

Diodes as per the previous post.

That all makes perfect sense. Thanks folks.

Steve. Nope I ain't going for no triangle, no way.