# Reversing loops and momentum on Aristocraft TE



## Spule 4 (Jan 2, 2008)

All-

The current plans for my branchline out of Nove Mesto is to have a return loop on the end, so a down train becomes up on return.

Now.....

The traditional method of reversing loops is total isolation, enter same direction at all times, the loop section is controlled with bridge for set direction travel, and manditory reverse of the throttle when the entire train (or at least the bits that pick up power, ie. loco, and pax cars with lighting) are in the totally isolated section.

However....

As a user of two 10 channel Aristocraft TEs, one has some momentum, the other has (unfortunately) more.

So the question is, will the movement through the loop work from the standpoint of being able to fully reverse before the departure of the train out of the other end, ie, preventing a dead short? 

I imagine enter the loop, estimate the distance of coast once reversed, hit the reverse on the throttle, which will give a "set speed - > slow -> stop - > slow - > return of set speed behavior?

This is anticipated by accidental hits of "reverse" during normal operations, not good for motors, but hey, does happen.


----------



## toddalin (Jan 4, 2008)

First off, it is not necessary to enter the loop the same way or even use a bridge rectifier. There are simple ways around this using the LGB EPL system or simple relay logic.

Second, the reversal of the power to the track has nothing to do with what happens at the TE. In other words, you don't need to touch your remote. It is all accomplished beyond the TE's control "at the track level."

At one time someone on this forum stated that the trains had to enter the same way and use the bridge and on a bet that it didn't, I came up with the following relay logic. This will work with dc, dcc, or any system that takes power from the track. BTW, he never paid up on the bet.


----------



## toddalin (Jan 4, 2008)

Sorry but this site has a REAL PROBLEM in that if you edit a post with a picture, you loose the picture and can't get it to appear again in that post. This new software is screwy! 

Anyway:


----------



## Spule 4 (Jan 2, 2008)

So the relays actually reverse the polarity of not just the loop but the remainder of the line outside the loop? 

Thanks, let me send this on to my dad (EE and 50+ year layout builder). Looks like a lot of work, the kind of stuff he likes!


----------



## krs (Feb 29, 2008)

Garrett - 

Don't know if the search capability on MLS was ever fixed, or do the search on MLS via google, but this subject on reverse loops in analogue layouts has been discussed in detail a number of times including this particular relay circuit.


There are many ways to accomplish this reverse loop operation - the simplest from a wiring and cost point of view is the diode bridge approach you originally mentioned.
I find that works best if you can incorporate a small station stop in the loop and use a manual switch that one can cut open but that lass back to its original position like the LGB manual switches.


Then there are various ways to control the polarity reversal using either a set of auxiliary contacts on LGB electric switches, or using a bi-polar latching relay or using the above relay circuit, but all of those require reed switches in the track and a magnet to trigger them on every loco that is expected to run through the reverse loop.

And then there is the latest version of the Massoth reverse loop controller which is designed to work for analog as well as for DCC.


- Knut


----------



## Spule 4 (Jan 2, 2008)

Hi Knut- 

Thanks, I thought about the station, and while there will be one (yet to be named) station there, that may be a solution for a manditory stop of all traffic. There will also be an industry to be shunted just up from the return loop, so there will be operational options with the loop itself. 

I will check the archives, but I have had some problems with searches, so I honestly did not even try...


----------



## toddalin (Jan 4, 2008)

Posted By krs on 08 Jun 2010 07:26 PM 
Garrett - 



Then there are various ways to control the polarity reversal using either a set of auxiliary contacts on LGB electric switches, or using a bi-polar latching relay or using the above relay circuit, _*but all of those require reed switches in the track and a magnet to trigger them on every loco that is expected to run through the reverse loop*_.

And then there is the latest version of the Massoth reverse loop controller which is designed to work for analog as well as for DCC.


- Knut 




No.

The principals of the Tortoise Bump Accident Sentinal System (Bump A.S.S.) can be applied and alleviate the need for the reed switches and magnets. The Bump A.S.S., documented here many times in the past, is a simple gap in the rails with an insulator on either side. When the engine or rail car crosses the gap, it shorts out this little section of track (about half the size of an LGB turnout frog) sending 6 volts to the relay triggering the system. It will work with any engine or rail car with metal wheels. Many here have seen the Bump A.S.S. in operation and watch in amazement for time on end.


----------



## Spule 4 (Jan 2, 2008)

Wait, the relay version requires a brief short? Not liking that if this is the case....


----------



## toddalin (Jan 4, 2008)

Posted By Spule 4 on 09 Jun 2010 08:11 PM 
Wait, the relay version requires a brief short? Not liking that if this is the case.... 

No, not a "short" circuit at all in any way or form. Maybe "shorts out the section" is a bad choice of words. 

OK, how about this. The wheels create a "bridge" (rather than short) that lets the current flowing through the track flow into that little section of track sending a pulse to the relay.


----------



## East Broad Top (Dec 29, 2007)

That sounds like the Massoth reverser as well. It's basically an unpowered section of rail (about 1" long) that is only powered when the train's wheels bridge power onto it (such as power flowing from the lead driver to the pilot truck, or the rear axle of a diesel power truck to the front axle.) The controller reads the polarity of this power, and compares it to the power forward of the insulated section of rail. If it's the same, it does nothing. If it's different, it changes the polarity to match. It's a pretty slick way to do business. No shorts, no magnets, just a few extra wires to run to the contoller (which can be located nearby in a building or some such). If I recall, the Massoth unit has some different wiring to run for regular DC track power (it needs a constant DC source to power the electronics), but that's it. The manual is on Massoth's web site if you want to check it out. 

Later, 

K


----------



## toddalin (Jan 4, 2008)

Posted By East Broad Top on 09 Jun 2010 09:16 PM 
That sounds like the Massoth reverser as well. It's basically an unpowered section of rail (about 1" long) that is only powered when the train's wheels bridge power onto it (such as power flowing from the lead driver to the pilot truck, or the rear axle of a diesel power truck to the front axle.) The controller reads the polarity of this power, and compares it to the power forward of the insulated section of rail. If it's the same, it does nothing. If it's different, it changes the polarity to match. It's a pretty slick way to do business. No shorts, no magnets, just a few extra wires to run to the contoller (which can be located nearby in a building or some such). If I recall, the Massoth unit has some different wiring to run for regular DC track power (it needs a constant DC source to power the electronics), but that's it. The manual is on Massoth's web site if you want to check it out. 

Later, 

K 
Yes, my concept very similar to what Massoth copied







, but simpler and far cheaper.


----------



## TonyWalsham (Jan 2, 2008)

Todd, 
Somebody copied the ideas of someone else? Never!!! 

Big Multi Nationals would never do that. Surely?


----------



## krs (Feb 29, 2008)

Posted By toddalin on 08 Jun 2010 11:30 PM 
The principals of the Tortoise Bump Accident Sentinal System (Bump A.S.S.) can be applied and alleviate the need for the reed switches and magnets. The Bump A.S.S., documented here many times in the past, is a simple gap in the rails with an insulator on either side. When the engine or rail car crosses the gap, it shorts out this little section of track (about half the size of an LGB turnout frog) sending 6 volts to the relay triggering the system. It will work with any engine or rail car with metal wheels. Many here have seen the Bump A.S.S. in operation and watch in amazement for time on end.



I know what you mean technically but I have never seen a description of that here on MLS (you write it has been documented on MLS many times).
I tried google using both terms - Tortoise Bump Accident Sentinal System and Bump A.S.S. - but all that came up was actually this particular thread on MLS, nothing else.


Could you post a link to some earlier MLS discussion on this product or a link to a product page if there is one?

I'm specifically interested in the voltage range it operates over and if it requires its own power or is powered by the track - cost would be another factor.


----------



## krs (Feb 29, 2008)

Posted By TonyWalsham on 09 Jun 2010 11:31 PM 
Todd, 
Somebody copied the ideas of someone else? Never!!! 

Big Multi Nationals would never do that. Surely?


Well, this is not exactly a new idea.
The H0 and N-scale people have had these more or less forever - don't know why none of the G-scale manufacturers ever produced one.


Here is a Version that was offered by Trix:










Marklin has a version, Arnold had one in N-scale - there are probably others.

And then people of course made their own:


----------



## SteveC (Jan 2, 2008)

Maybe this will help.

Traditional Power/Topic: Track sensor/switch - 30 Dec 2003[/b]

Traditional Power/Topic: SWITCH TRACK STIGNALS - 03 May 2004[/b]

Traditional Power/Topic: Diodes: Size and rating for track use? - 24 Jan 2005[/b]

Traditional Power/Topic: Secrets of the Tortoise Bump Accident Sentinal Sys - 23 Jan 2006[/b]

Traditional Power/Topic: LED Circuit Question - 17 Sep 2006[/b]

Traditional Power/Topic: Basic DC track questions but I have to ask them - 26 Oct 2006[/b]

Traditional Power/Topic: Semi-autonomous trains? - 03 Feb 2007[/b]

Traditional Power/Topic: Remote Parking of Trains? - 13 Jun 2007[/b]

Traditional Power/Topic: Looking for signal circuits - 23 Jul 2007[/b]

Beginner's Forum/Topic: Crossing - collision prevention - 05 Jul 2005[/b]

Beginner's Forum/Topic: How to detect train to activate accessories - 07 Apr 2007[/b] 

Beginner's Forum/Topic: block signaling - 03 Feb 2008[/b] 

Beginner's Forum/Topic: how can I do this (crossing question)? - 24 Feb 2008 11:26 AM[/b] 

Traditional Power/Topic: Block Signals - 03 Mar 2009 10:37 AM[/b]

Traditional Power/Topic: wiring reverse loops - 24 Aug 2009 01:44 PM[/b]


----------



## krs (Feb 29, 2008)

Thanks Steve - 

This is actually the thread that describes the concept, all the other ones just refer to it.









http://www.mylargescale.com/Community/ForumArchives/tabid/100/Default.aspx?TOPIC_ID=36352 
Turns out that I had seen this at the time, the name chosen for this concept just didn't stick in my mind - Tortoise Bump Accident Sentinal System - still not sure what the name is supposed to mean.


But a general question - one of the earlier threads mentions that Lewis Polk decided to commercialize a similar concept by Atlas rather than this concept.
Is there actually an Aristocraft product that implements this concept? I wasn't aware of one.

- Knut


----------



## East Broad Top (Dec 29, 2007)

Todd, if I'm reading your schematic correctly, you're isolating only one rail for the detection, the other is continuous. Simplistically speaking, it's essentially an electronic version of a magnetic reed switch. For a reverse loop, you've got to gap both rails. I'm not sure how that plays into the schematic as you've posted it. Would you have two of these circuits on either side of the gap, or is there a different schematic for wiring it for reverse loop applications? 

Later, 

K


----------



## kormsen (Oct 27, 2009)

the point is, that the short piece of rail is part of a seperate circuit, and is NOT connected to the trackpower. 
powerpack - > piece of rail -> gap -> rail -> switch (to change polarity of trackpower) -> powerpack


----------



## krs (Feb 29, 2008)

I find the schematic rather hard to follow because it's drawn in such an unconventional manner.

In fact, I had to redraw it to actually see the details.

The specific schematic I was looking at:










is a modified version of the basic circuit (which I assume was posted at some earlier date on MLS - not one of the links Steve posted) for a specific application.

The basic circuit would be the diode bridge connected between theinsulated trigger portion of the track on one side and the other rail on the other side of the AC input of the bridge.
The positive side of the bridge feeding the 6 volt regulator which in turn drives the relay.

With the components show, one would need about 8.5 volts on the rails to activate the circuit - there is a 1.4 volt drop across the rectifier bridge and about a 1 to 1,5 volt drop required across the regulator.
By using Schottkey diodes for the bridge andf a low drop-out regulator, one can reduce that activating voltage a bit.

I would also add a snubber diode across the relay coil to be on the safe side and protect the output device of the regulator.

It might help with the understanding of the circuit if someone redrew the base schematic (the one on the left) in a conventional manner.


- Knut


----------



## East Broad Top (Dec 29, 2007)

the point is, that the short piece of rail is part of a seperate circuit, and is NOT connected to the trackpower. 

Absolutely. That part I understand. The problem is, in a reverse loop, you've got to gap both rails to avoid the short, and you've got to do it on both ends of the loop (usually--but not necessarily--shortly after the switch). The Massoth unit uses 4 of these isolated sections of rail as part of the circuit; two on each end of the loop. These isolated sections create the gaps in both rails needed to eliminate the short. Todd's circuit diagram (shown above) only shows one sensor, with no indication as to how it controls the polarity of the loop, which would still need to be gapped to avoid the short. I think it's a neat system, and not having to install magnets on your locos definitely has merit (especially if you've already got magnets for triggering sounds). I'm just trying to figure out how it works as a system. I reviewed the Massoth unit for GR a few months ago, and was quite impressed with it. I'm keen to get my head wrapped around this system as well. I'm definitely all for cool, simple, and innovative ways to make DC track wiring easier. Later, K


----------



## krs (Feb 29, 2008)

Todd's schematic from one of the earlier links shows the application of this trigger circuit for one specific application that had nothing to do with reverse loops.

His original point was - when I commented that one needs a magnet on the loco and a reed switch to control some of these reversing circuits we discussed earlier in this thread, that
this "tortoise" circuit could be used instead of the magnet/reed switch option.

I redrew the basic circuit here:










Well - it's up on my MLS webspace but for some reason when I try to insert the sketch all I get is a blank page.

(PS - Sorry, the drawing did show up just not here in the location where it was supposed to be. 


Try this link:

http://1stclass.mylargescale.com/krs/G Scale Trigger Circuit.jpg


Each one of these circuits replaces the conventional magnet/reedswtich combination except of course that you don't need a magnet and that this circuit will also trigger with some cars, for instance lit passenger cars that pick up power from the track. You still need the rest of any of the reversing circuits that were discussed.


For use as the trigger device for a reversing loop, I would make it more sensitive - use a 3VDC DIP relay for instance with either 1 or 2 amp contacts which is plenty for that application, and use Schottky diodes and a low drop-out regulator.

The last thing you want in a reversing loop circuit is the possibility that it doesn't trigger and you end up with a short.

- Knut


----------



## East Broad Top (Dec 29, 2007)

Thanks. That's kind of what I thought was going on, but wasn't sure. It's not quite identical to the Massoth reverser, but works on the same basic principle and in conjunction with Todd's first diagram does the same job. 

Later, 

K


----------



## toddalin (Jan 4, 2008)

Posted By East Broad Top on 10 Jun 2010 11:34 AM 
Thanks. That's kind of what I thought was going on, but wasn't sure. It's not quite identical to the Massoth reverser, but works on the same basic principle and in conjunction with Todd's first diagram does the same job. 

Later, 

K 

OK Kevin, if you go back and look at the provided diagram, there are double gaps at the rails leading into the loop.

When I first dreamt up the _Tortoise Bump Accident Sentinal System_ (Bump A.S.S.) it was to protect a 30 degree crossing on the _Tortoise & Lizard Bash RR_. The track gaps detect an oncoming train and open a relay for the block of the opposing traffic so when it approaches the crossing it stops and waits. I did not want to rely on magnets and reed switches to accomplish this all important task and it had to work with anything and everything I would throw at it. The duration that it waits is set by pot on the 555 chip and it is simply a matter of setting it long enough for the train to clear the crossing and reach the track gap on the other side (which retriggers the 555) before releasing the other train. _ Hence the name Tortoise Bump Accident Sentinal System (Bump A.S.S.)._

I asked Lewis Polk if they were interested in the system and he said that they were, but only to activate a set of lights. Hence the schematic that was posted. Note that it is used to control a pair of LEDs and nothing else. I built Lewis a prototype and sent it off to their engineering department. While they liked the concept and paid me for the prototype, Lewis said that they had decided to go with the Atlas system under development, that also used a similar track gap scenario. Unforetunately, the Altas system got tied up in development and well... never happened.

The schematic, as shown takes its power from the track. It works extremely well down to ~7-8 volts and is fine for protecting the crossing as we never run our trains that slow though it. But as I inferred, the system can be made even easier and cheaper and will work _at any track voltage _simply by giving it its own power supply. This can be any voltage just so that the voltage matches the relays.

Let's say we want to use 6 volt relays. We buy a 6 volt wall wart for $


----------



## SteveC (Jan 2, 2008)

Posted By krs on 10 Jun 2010 08:48 AM 
_{snip...}_ This is actually the thread that describes the concept, all the other ones just refer to it. _{snip...}_
Actually, no, there are four topics in the above that have an explanation of the circuit.


----------



## krs (Feb 29, 2008)

Posted By SteveC on 10 Jun 2010 03:35 PM 
Posted By krs on 10 Jun 2010 08:48 AM 
_{snip...}_ This is actually the thread that describes the concept, all the other ones just refer to it. _{snip...}_
Actually, no, there are four topics in the above that have an explanation of the circuit.










Yes - that is probably true.
I just scrolled through each of the links quickly looking specifically for a schematic - all the other schematics I saw were identical to the first, so I just kept going looking for something different.

Do any of the other links provide any additional information?

- Knut


----------



## toddalin (Jan 4, 2008)

Posted By krs on 10 Jun 2010 05:42 PM 
Posted By SteveC on 10 Jun 2010 03:35 PM 
Posted By krs on 10 Jun 2010 08:48 AM 
_{snip...}_ This is actually the thread that describes the concept, all the other ones just refer to it. _{snip...}_
Actually, no, there are four topics in the above that have an explanation of the circuit.











Do any of the other links provide any additional information?

- Knut 




Get it right from the horse's mouth. What would you like to know?


----------



## krs (Feb 29, 2008)

Well - I'm always interested how well a circuit functions at the extremes.
For instance: 


You wrote:

>>And, it works with ANY engine or rail car with metal wheels, not just lighted ones.  When a metal wheel crosses the rail insulator it touches both the outter section of rail and the short insulated section twice (coming and going) as does every subsequent rail car. So there is LOTS OF REDUNDANCY in the system and even if one wheel faisl to properly bridge the gap, many others will.


----------



## toddalin (Jan 4, 2008)

Posted By krs on 10 Jun 2010 08:04 PM 
Well - I'm always interested how well a circuit functions at the extremes.
For instance: 


You wrote:

>>And, it works with ANY engine or rail car with metal wheels, not just lighted ones. When a metal wheel crosses the rail insulator it touches both the outter section of rail and the short insulated section twice (coming and going) as does every subsequent rail car. So there is LOTS OF REDUNDANCY in the system and even if one wheel faisl to properly bridge the gap, many others will.


----------



## Spule 4 (Jan 2, 2008)

Anyhow.....


We are back to using a simple diode method (should have never sold the LGB reversing loop sets I had) and a manditory station stop due to the geographical location of the loop on the railway anyhow. 


The Massoth reverser might be a future option for any run through of freight (mineral, limited LCL and petroleum service in this end of the railway on other sidings) while stops are obvious passenger service for trains (railbus service on a dedicated siding).
This will keep the reverse method simple and deal with the momentum "feature"







of the TE.


----------



## toddalin (Jan 4, 2008)

Posted By Spule 4 on 10 Jun 2010 09:26 PM 


Anyhow.....


We are back to using a simple diode method (should have never sold the LGB reversing loop sets I had) and a manditory station stop due to the geographical location of the loop on the railway anyhow. 


The Massoth reverser might be a future option for any run through of freight (mineral, limited LCL and petroleum service in this end of the railway on other sidings) while stops are obvious passenger service for trains (railbus service on a dedicated siding).
This will keep the reverse method simple and deal with the momentum "feature"







of the TE.




OK Spule 4, nothing personal intended, but this is for KRS.

This is exactly why I typically don't go into great detail with my circuits. Over 99% of the people aren't interested. Of those that are, most are familiar enough with electronics and the concepts that if presented with the idea (Gee whiz, why didn't I think of that!), they can recognize what it takes to carry though and make it work, even if it is putting a diode or capacitor across a relay to make it work or knowing that a diode is a rectifier diode rather than a signal diode. Those that want to try to construct the circuit but don't have the familiarilty will ask for help, and always receive it.

But when most are presented with anything that looks like a road map of wire, they turn tail and run. There were those that thought that wiring the relays on the Tortoise Loop Control was too complicated. Sorry, but I even color coded the lines and can't make it any simpler than that.

Of the 5 or so years I've been posting these circuits, I don't know that anyone has actually followed through and built any.


----------



## Spule 4 (Jan 2, 2008)

Toddalin et al- 

I have some people (two EEs) very interested in the diagram. It is just for my needs, that the simple diode situation is the best for now (not my suggestion, but someone elses off-board). Not saying that your method will or will not work, but right now it is not the direction I would need to go if we will be stopping all trains anyhow? 

As far as reading it/understanding it. I did not break it down step by step myself (I have been on the road for work all week) but having worked on, and even re-wired (fire/melted harness) a few 1960s-1980s era European cars with realys to control some aspects of them (horns, lights, etc.) I get the general concept and kind of like your application of them in this service. Actually, it is a clever solution. 

However, I habe also dealt with relays that stick, fail etc. So in cases where one can go "solid state" this may be a better solution (until you fry something, then you are sunk). 

The one question unfortunately that was never addressed, or in other wiring in the MLS threads, but then maybe I did not ask the question correctly, is how to handle the momentum situation? As this will STILL be a problem, even with the diodes, if one "over runs" the breaks in the loop? (zap!)


----------



## toddalin (Jan 4, 2008)

Posted By Spule 4 on 11 Jun 2010 04:48 AM 
Toddalin et al- 

The one question unfortunately that was never addressed, or in other wiring in the MLS threads, but then maybe I did not ask the question correctly, is how to handle the momentum situation? As this will STILL be a problem, even with the diodes, if one "over runs" the breaks in the loop? (zap!) 


As I noted, momentum has no bearing on the system nor does stopping the trains within the loop. If you were to try to run the train into and around the loop and stop, or have not yet reached the proper "trigger" whether it be a track gap or reed switch, the loop polarity is still in sync with the main line.

If you got far enough around the loop, either by driving it around, or because of the momentum carried you around, and came to the "trigger" you would sync the mainline with the loop, but nothing actually changes within the loop so the train is fine as long as it is still within the loop.

If you got far enough around the loop, and activated the trigger and stopped the train still within the loop and the momentum carried it out to the mainline, no problem because the trigger has synced the main line and loop together.

Maybe I'm just not understanding your concern?


----------



## krs (Feb 29, 2008)

Posted By toddalin on 10 Jun 2010 08:46 PM 
1. I can run trains through the crossing at speeds generated by 20+ volts. When I do, I hear the relays clicking as each wheel hits the gap. The system has never failed in this respect. 
2. I can use either PWC or linear power on my TEs and either works fine.

3. Works fine down to between 7-8 volts as shown. Use lower voltage relays and you can go maybe a couple volts lower. (The chip needs about 4.5 volts to operate.) It can work with _*any track voltage*_ if provided with its own power supply.

4. Yes. As I noted, it is not necessary to use the bridge rectifiers and voltage regulators if the system is powered by a wall wart (or 6 volts worth of batteries for that matter). This simplifies the circuit (the detector is now just the relay and the rectifier/regulator are not necessary for the timing circuit).

There is no sense trying to further improve upon something that is working fine to begin with and has been working fine in active service for the last 5+ years.





I must say I expected more than "I tried it and it works fine" as an answer.

But let's just leave it at that - however, I don't see how the detection will work at _*any track voltage*_ even if one provides a separate power supply.

Current still has to flow through the detection diode bridge and whatever drives the relay.

I just measured the minimum DC voltage at the track that will still run the LGB 2010 Stainz - 1.85 VDC using a standard LGB power pack.

The existing circuit would certainly not detect a voltage pulse of this magnitude even with a separate power supply.

How would you modify it to work?

-- Knut


----------



## krs (Feb 29, 2008)

Posted By toddalin on 11 Jun 2010 10:55 AM 
If you got far enough around the loop, and activated the trigger and stopped the train still within the loop and the momentum carried it out to the mainline, no problem because the trigger has synced the main line and loop together. 
Maybe I'm just not understanding your concern?


Remember - *there is no trigger!*

Garrett is using the diode bridge approach for his reverse loop - the polarity has to be reversed while the train is in the reversing section that is powered via the diode bridge and with the momentum feature that may not be possible.

The only thing that comes to mind as a possible solution is to not reverse the direction at all with the TE but use a separate external DPDT switch to do that. 
One could for instance set that up somewhat automatically by using the auxiliary contacts on an LGB turnout and then throwing the turnout when the train is in the reverse loop.

-- Knut


----------



## toddalin (Jan 4, 2008)

Posted By krs on 11 Jun 2010 02:24 PM 

1. I must say I expected more than "I tried it and it works fine" as an answer.

2. I don't see how the detection will work at _*any track voltage*_ even if one provides a separate power supply.

Current still has to flow through the detection diode bridge and whatever drives the relay.

3. I just measured the minimum DC voltage at the track that will still run the LGB 2010 Stainz - 1.85 VDC using a standard LGB power pack.

The existing circuit would certainly not detect a voltage pulse of this magnitude even with a separate power supply.

How would you modify it to work?

-- Knut 


1. If you want a more definitive answer, breadboard one for yourself. I'm not about to disassemble something that has been working perfectly for years nor am I your R&D department.


2. Then you don't understand basic electronics and the use of a common rail. As I noted, if given its own power supply, it is simply a matter of putting the relay voltage to the rail, and letting the wheel span the gap to trigger the relay. What bridge is involved?

3. It doen't need to detect 1.85 volts. It only needs to detect the 6 volts for the trigger that you feed into the rail from the wall wart/battery.

As I keep saying, using a separate power supply the rectifers/regulators are removed from the circuits. The trigger is simply the track gap and when a wheel spans it or an engine or lighted car pass over the gap, this lets the 6 volts flow to the relay. The rail doesn't don't care if it carries one leg of the a power supply for the engine (regardless of voltage) and one leg of a separate power supply for the trigger of the Bump A.S.S. at the same time. You should know that. 

Similarly, there is no need for the rectifier/regulator on the chip set because you're providing a continual 6 volt source.

Now this is where you say, "Gee Whiz, Why didn't I think of that!"


----------



## toddalin (Jan 4, 2008)

Posted By Spule 4 on 11 Jun 2010 04:48 AM 
Toddalin et al- 

The one question unfortunately that was never addressed, or in other wiring in the MLS threads, but then maybe I did not ask the question correctly, is how to handle the momentum situation? As this will STILL be a problem, even with the diodes, if one "over runs" the breaks in the loop? (zap!) 

If you are intent on using the bridge rectifier and you don't want to stop the trains, you must do it "at the track level." See the included diagram.


----------



## toddalin (Jan 4, 2008)

BTW, as an after thought, I see no reason why the reed switches in the provided diagram could not be replaced by the Bump A.S.S. track gap method with just minor modification to the circuit. Also, the probably hard to find latching relay could be replaced by a few conventional relays that would perform exactly the same provided you don't turn off the power while operating. 

(BTW, I would have added this to my last post, but that would have destroyed the graphic as editing posts seems to do.)


----------



## krs (Feb 29, 2008)

Posted By toddalin on 11 Jun 2010 04:58 PM 
1. If you want a more definitive answer, breadboard one for yourself. I'm not about to disassemble something that has been working perfectly for years nor am I your R&D department.

2. Then you don't understand basic electronics and the use of a common rail. As I noted, if given its own power supply, it is simply a matter of putting the relay voltage to the rail, and letting the wheel span the gap to trigger the relay. What bridge is involved?

3. It doen't need to detect 1.85 volts. It only needs to detect the 6 volts for the trigger that you feed into the rail from the wall wart/battery.

As I keep saying, using a separate power supply the rectifers/regulators are removed from the circuits. The trigger is simply the track gap and when a wheel spans it or an engine or lighted car pass over the gap, this lets the 6 volts flow to the relay. The rail doesn't don't care if it carries one leg of the a power supply for the engine (regardless of voltage) and one leg of a separate power supply for the trigger of the Bump A.S.S. at the same time. You should know that. 

Similarly, there is no need for the rectifier/regulator on the chip set because you're providing a continual 6 volt source.

Now this is where you say, "Gee Whiz, Why didn't I think of that!"




Wow!

First you offer to answer any questions

Get it right from the horse's mouth. What would you like to know?

and then all I get is snarky comments.

As to common rail and occupancy detection, that requires that the car draws power from the track last time I looked, just a single metal wheel which is what we are talking about would not do it.

Could you post a sketch how this is supposed to work?


-- Knut


----------



## toddalin (Jan 4, 2008)

Posted By krs on 11 Jun 2010 06:10 PM 
Posted By toddalin on 11 Jun 2010 04:58 PM 
1. If you want a more definitive answer, breadboard one for yourself. I'm not about to disassemble something that has been working perfectly for years nor am I your R&D department.

2. Then you don't understand basic electronics and the use of a common rail. As I noted, if given its own power supply, it is simply a matter of putting the relay voltage to the rail, and letting the wheel span the gap to trigger the relay. What bridge is involved?

3. It doen't need to detect 1.85 volts. It only needs to detect the 6 volts for the trigger that you feed into the rail from the wall wart/battery.

As I keep saying, using a separate power supply the rectifers/regulators are removed from the circuits. The trigger is simply the track gap and when a wheel spans it or an engine or lighted car pass over the gap, this lets the 6 volts flow to the relay. The rail doesn't don't care if it carries one leg of the a power supply for the engine (regardless of voltage) and one leg of a separate power supply for the trigger of the Bump A.S.S. at the same time. You should know that. 

Similarly, there is no need for the rectifier/regulator on the chip set because you're providing a continual 6 volt source.

Now this is where you say, "Gee Whiz, Why didn't I think of that!"




Wow!


As to common rail and occupancy detection, that requires that the car draws power from the track last time I looked, just a single metal wheel which is what we are talking about would not do it.

Could you post a sketch how this is supposed to work?


-- Knut 





No, it doesn't. All it has to do is provide a path. See diagram for block occupancy detector that will change lights as trains proceed through.


----------

