CSX RobertJust remember that green does not mean go!
This came up as an issue in the wake of Three Mile Island where the semantics of emergency response were confused. One response in ITU group R10 was to provide repeaters for the remote valves that displayed 'correct' position as red and green (or yellow for transition) with blink modulation for more information, independent of the flow circuit meaning. Note that all the aspects were achievable with one bicolor LED per valve...
richhotrain I have followed this thread with interest, but I have not contributed since I am not a DC guy. So, when I saw your PM comment, I was disappointed that a solution to your issue might not become public. I do understand how you felt about the nature of the responses that you were getting.
I am a DC guy, and I am staying out of this one.
-Kevin
Living the dream.
Ablebakercharlie Thank you Mel and CSX Robert, Yes, polarity mismatch would have been a mutch better title for my question. If I was more experienced I probably would have used that title. But if I was more experienced I probably wouldn't have asked the question in the first place. The easiest solution is to use a bi-color LED as I have 12v bi-color LED's and I can solder them right in and be good to go. Maybe I am being silly for not originally being happy with accepting two different colors to mean the same thing. I still have to decide if that is going to annoy me if I put them on the control panel. The most elegant is surely Mel's and he has suggested to me a way to go about that. But I had to ask it there was another solution. It would have gnawed at me if I didn't. Hopefully we can put this thread to rest. I am a satisfied customer.
Yes, polarity mismatch would have been a mutch better title for my question.
If I was more experienced I probably would have used that title. But if I was more experienced I probably wouldn't have asked the question in the first place.
The easiest solution is to use a bi-color LED as I have 12v bi-color LED's and I can solder them right in and be good to go. Maybe I am being silly for not originally being happy with accepting two different colors to mean the same thing. I still have to decide if that is going to annoy me if I put them on the control panel.
The most elegant is surely Mel's and he has suggested to me a way to go about that.
But I had to ask it there was another solution. It would have gnawed at me if I didn't.
Hopefully we can put this thread to rest. I am a satisfied customer.
Rich
Alton Junction
CSX Robert Just remember that green does not mean go!
Just remember that green does not mean go!
AblebakercharlieThe best and easiest solution is to use a bi-color LED. I have 12v bi-color LED's and I can solder them right in and be good to go. It really is the most elegant solution and I am being silly for not accepting it as such.
RR_Mel CSX Robert jjdamnit How, with only one "color" illuminated to indicate polarity... Ablebakercharlie He doesn't want to indicate polarity, he only wants to indicate a mismatch in polarity. jjdamnit No matter what the "elegant solution" the OP is seeking, the physics of electrons dictates the outcome, no matter how much they want it. RR_Mel's circuit is the exact "elegant solution" Ablebakercharlie wants. Polarity mismatch, problem, LED on and always the same color - polarity the same, no problem, LED off. Thank you, I think we all missed not using the words “Polarity mismatch”.That is what he was looking for. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
CSX Robert jjdamnit How, with only one "color" illuminated to indicate polarity... Ablebakercharlie He doesn't want to indicate polarity, he only wants to indicate a mismatch in polarity. jjdamnit No matter what the "elegant solution" the OP is seeking, the physics of electrons dictates the outcome, no matter how much they want it. RR_Mel's circuit is the exact "elegant solution" Ablebakercharlie wants. Polarity mismatch, problem, LED on and always the same color - polarity the same, no problem, LED off.
jjdamnit How, with only one "color" illuminated to indicate polarity... Ablebakercharlie
He doesn't want to indicate polarity, he only wants to indicate a mismatch in polarity.
jjdamnit No matter what the "elegant solution" the OP is seeking, the physics of electrons dictates the outcome, no matter how much they want it.
RR_Mel's circuit is the exact "elegant solution" Ablebakercharlie wants. Polarity mismatch, problem, LED on and always the same color - polarity the same, no problem, LED off.
Thank you, I think we all missed not using the words “Polarity mismatch”.That is what he was looking for. Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
Thank you Mel and CSX Robert,
This is getting downright comical. Ablebakercharlie posted a question, admittedly confusing at first but he has explained his wiring and what he wants to accomplish. A simple and elegant solution has been posted, yet people are still posting alternative solutions that don't do what he wants because "it can't be done."
As far as all the suggestions to use a bicolor LED: that would mean no light is good, red light is bad, and green light is bad, I can certainly see why he wouldn't want that.
jjdamnitHow, with only one "color" illuminated to indicate polarity... Ablebakercharlie
jjdamnitNo matter what the "elegant solution" the OP is seeking, the physics of electrons dictates the outcome, no matter how much they want it.
Hello All,
CSX RobertAs has been mentioned, a bridge rectifier will do it.
How, with only one "color" illuminated to indicate polarity...
AblebakercharlieI need a light source that will light going in both directions.
What the OP is trying to do is ON/ON with no differentiation in color to indicate electron flow.
However, the OP does mention a difference in lumens to cue them on the polarity.
However, they do not want a complete On/Off solution.
A few lumens difference in a single LED...
AblebakercharlieWhen I am operating the trains and hitting all those DPDT switches like mad I sometimes forget what the polarity of a certain block is.
Won't really help.
RR_MelMy solution is a single LED, on for wrong polarity - attention needed, LED off for correct polarity, no attention needed.
But...
Ablebakercharlie...not an elegant solution in my opinion.
No matter what the "elegant solution" the OP is seeking, the physics of electrons dictates the outcome, no matter how much they want it.
AblebakercharlieI am just being stubborn and only want one color light to indicate a polarity discrepancy.
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
cv_acrNo it won't. It'll make a single light be constantly on regardless of polarity. Not sure how that would help "detect" the polarity and indicate which blocks have opposing polarity. He doesn't want to "correct" the polarity; [if I understand correctly] he wants to see which blocks have a "westbound" or "eastbound" polarity. (He's definitely doing something a little unusual.) I'm with jj; not sure how a single colour indicator can indicate three states (off, "normal" polarity, "reverse" polarity) You really need two lights/colours.
He's not wanting to know "eastbound" or "westbound" polarity, he just wants to know if they match (more specifically, a light that is on when they don't).
At a block boundary, you have four rails, for example, A1 and B1 at the end of block 1 and A2 and B2 at the end of block 2. You wire the rectifier and led across the boundary on the same rail side, A1-A2, or B1-B2.
If the polarity between the two blocks matches, there will be no voltage potential across the boundary, it will be + and +, or - and -, so the led will not light.
If the polarity between the blocks does not match, you will have a voltage potential across the boundary, either + and -, or - and +. Either way, the bridge rectifier will feed the led with the correct polarity and it will light.
Ablebakercharlie I am a visual person so if I have a light on my panel on the frontier between two blocks that can illuminate to tell me that I better change the polarity of the upcoming block or I'll get a short then I can keep the train merrily on its way.
If you allow going back to the idea of a bi-colour, or two LEDs...
A simple bi-polar/bi-colour LED, or separate red and green LEDs (and appropriate dropping resistor) wired in opposite directions across the track power would show red on the panel for one polarity and green for the other..
If on the panel you have two red lights beside each, or two green lights beside each other: good. Red and green lights beside each other: bad. (You could even provide an indicator at each end of each block on the board, so you can easily see the pairs of lights at each boundary.)
This would easily show which blocks have power (if you wire it in parallel across the power lead, it'll draw its own power and light up even if no train is in the block) and where your polarities are. Probably the easiest solution to wire.
Chris van der Heide
My Algoma Central Railway Modeling Blog
Ablebakercharlie I am just being stubborn and only want one color light to indicate a polarity discrepancy. To me the color of a light should mean something and using two colors to mean the same thing in not an elegant solution in my opinion.
A simple LED by itself already, inherently does "what you want" your light to do. Because it is a diode it only conducts in one direction or 'polarity' and not in the other (over the full range of significant current and voltage for model-railroad propulsion) and, because it is light-emitting in conduction it only lights in one polarity and not the other.
The beauty of the bicolor device is that it actually has two diodes side-by-side, operating in opposite directions. The actual 'diode' is very small, about the size of a piece of granulated sugar, so it is relatively easy to mount the two cores to common leads. Now one DC polarity will light one of the cores with the power on; reversing the polarity will light the other one. This does not help what you want the light to do (and worse yet it is difficult to modify the device so it lights in only one direction) but if you need a polarity detector that unambiguously shows both presence of DC power and its polarity, a bicolor device accomplishes the task with tiny parts count, no moving parts, tiny power draw, and enormous lifetime.
(Incidentally for those modeling searchlight signals, putting AC across a bicolor LED produces a yellow to orange color, and since AC need not be symmetrical if is possible to 'turn on' one of the cores longer than the other per cycle and thereby 'tune' the color over an interesting range...)
I still think you should PM one of the people here who have arranged 'preselector' control of routes by cab -- the 'next' block to be occupied is switched on to proper polarity before a given cab's train reaches it, so there is never a chance of a locomotive bridging the gap and shorting if a polarity switch isn't thrown in time or is mistakenly thrown the wrong way in error.
CSX Robert jjdamnit How do you expect one color to represent two (2) different states of electron flow positive and/or negative? As has been mentioned, a bridge rectifier will do it.
jjdamnit How do you expect one color to represent two (2) different states of electron flow positive and/or negative?
As has been mentioned, a bridge rectifier will do it.
No it won't. It'll make a single light be constantly on regardless of polarity.
Not sure how that would help "detect" the polarity and indicate which blocks have opposing polarity.
He doesn't want to "correct" the polarity; [if I understand correctly] he wants to see which blocks have a "westbound" or "eastbound" polarity. (He's definitely doing something a little unusual.)
I'm with jj; not sure how a single colour indicator can indicate three states (off, "normal" polarity, "reverse" polarity) You really need two lights/colours.
CSX Robert Ablebakercharlie Hence the suggestion from Mel to use a voltage limiter or Overmods' suggestion to use a buck booster. Both will give me a consistant voltage to feed the lights, no matter what voltage I use. Just to be clear, Mel's circuit uses a current limiter.
Ablebakercharlie Hence the suggestion from Mel to use a voltage limiter or Overmods' suggestion to use a buck booster. Both will give me a consistant voltage to feed the lights, no matter what voltage I use.
Just to be clear, Mel's circuit uses a current limiter.
Got it - sorry - wrong word. Learning about electricity is like learning a new language and I get the words messed up sometimes.
jjdamnit "Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
AblebakercharlieHence the suggestion from Mel to use a voltage limiter or Overmods' suggestion to use a buck booster. Both will give me a consistant voltage to feed the lights, no matter what voltage I use.
My solution is a single LED, on for wrong polarity - attention needed, LED off for correct polarity, no attention needed.I use it as a reminder to do something. I have a wye at the end of my loop and the LED on is a reminder that requires reversing the polarity to prevent an operational running problem. If the LED is on a toggle switch needs to be operated to prevent shorting. Super simple, LED on Do Something.Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
jjdamnitHow do you expect one color to represent two (2) different states of electron flow positive and/or negative?
If you are only running one locomotive, why the need to use an auxillary method to change directions (reverse polarity) with it is already built into the cab?
You seem to want to make your wiring more complicated than necessary and disregard physics.
Good luck.
How do you expect one color to represent two (2) different states of electron flow positive and/or negative?
I didn't know, that is why I wrote a post to ask the question to see if there was a solution. Although, from my experiments an incadecsent seemed like the right direction to go in.
jjdamnit So, as I understand you have the cab (throttle) set at a given speed for a locomotive on the "mainline" and then, without varying the speed you toggle the switch to another block with a locomotive and "shock" it into moving and then to stop it you "kill" the section. Then to reverse this same unit you "shock" it into the other direction via the switch. The problem you run with this "shock" & "kill" method is you can do physical damage to the plastic running gear(s) of the locomotive(s). Cracked drive train components are very common with certain brands. Adding this stress can exacerbate the problem.
So, as I understand you have the cab (throttle) set at a given speed for a locomotive on the "mainline" and then, without varying the speed you toggle the switch to another block with a locomotive and "shock" it into moving and then to stop it you "kill" the section. Then to reverse this same unit you "shock" it into the other direction via the switch.
The problem you run with this "shock" & "kill" method is you can do physical damage to the plastic running gear(s) of the locomotive(s).
Cracked drive train components are very common with certain brands. Adding this stress can exacerbate the problem.
Hello Bobby ,
Thanks for responding. Didn't mean to put you in a spot with the PM post.
Let me clarify my operating method. The goal of operation is to have a train operating without shortcircuits. What was happening was a train would go from one block and enter the next block with the wrong polarity and then stop because of the short circuit. I am trying to avoid that with visual cues.
So if I am understanding you correctly I am not shocking the engines, in fact just the opposite. I want them to run as smoothly as possible from one block to the next with no sudden stops and starts.
I think everyone is getting hung up on the running two engines at once with only one cab. If I took that out of the equation would everyone feel better?
I really don't want to get a second powerpack right now. Getting my tortoises and bluepoints installed and starting on the scenery is the priority right now.
And if I can ever figure out how to embed a picture in a post instead of a link I would be most happy to share my progress with the community and invite comments!
Thanks again for your thoughtful reply,
charles
Ablebakercharlie...only want one color light to indicate a polarity discrepancy. To me the color of a light should mean something and using two colors to mean the same thing in (is) not an elegant solution in my opinion.
Your only solution would be a single lamp; incandescent or LED, to indicate a singular polarity- -"On" or "Off" to the particular track section.
"Off" of the "indicator" lamp meaning the polarity has transposed to the other track.
The "elegant" solution you are seeking is dictated by the physics of electrons.
In DC wiring, despite what you have done, is based on positive (+) and negative (-) polarity, commonly expressed as red (+) and black (-) colored jackets on the wiring.
AblebakercharlieI am just being stubborn...
wjstixBTW I'm still not clear, given what you want to do, why bi-color LEDs wouldn't work?
It would totally work! I am just being stubborn and only want one color light to indicate a polarity discrepancy. To me the color of a light should mean something and using two colors to mean the same thing in not an elegant solution in my opinion.
I was going to ask you if I could share your PM, but I see you already have.
AblebakercharlieThe idea of polarity indicator lights comes straight from p. 28 of my Andy Sperandeo's 1990 edition of Easy Model Railroad Wiring when he offers this technique as a visual solution to remembering to switch polarity on reverse loops.
Thank you for sighting your source.
What Andy Sperandeo is talking about is different to the solution you are seeking.
AblebakercharlieI have one throttle and yes, I sometimes run two trains at once although not for any extended period of time.
It has been said that running trains in DC with block wiring is like playing piano with one hand."
AblebakercharlieWhy the DPDT switches - remember, this is DC not DCC. I want the ability to have trains be able to go in different directions on different blocks at the same time. Also, with stand alone blocks, if there is a wiring issue I can easily isolate the problem and address it. Maybe a more experienced person wouldn't need this technique but for me I think it works nicely.
As I posted earlier, unfortunately, you have taken this circuitry as far as physics will allow.
At this juncture, in my opinion, you have three paths:
You can keep what works for you and slow down the speed of your operations to accommodate how your pike is currently wired and how fast you can process these movements.
Or, as posted earlier, explore two (2) cab block control with common wiring. Getting The Complete Atlaswiring book will be a great addition to your model train library and allow you to "wrap your head around" what is possible.
Finally, take the jump to a simple DCC system before you start throwing time and money that could be better put towards DCC.
Because of the popularity of DCC, DC cabs are cheaply available on auction sites like eBay.
You already have the bulk of the switches and wiring so converting would not be a huge outlay of finances.
Please understand what you want to achieve in the short term, might be a larger headache and expenditure in the long term, but is achievable (see my signature).
Sorry to be the "Bobby Bummer".
gregcwouldn't a single led-resistor across the rails be sufficient? of course they all go off if powered by the track
Let me preface by saying that I do NOT purport myself to be an electriciy whiz. Not even close.
But without having to write a lot of words the short answer is no - it won't work using one rail as the LED lights only when the electricity is going in one direction and I need a light source that will light going in both directions.
Hence, Andy S's suggestion in his book is to use a 16v to 18v bulb. I used a 12v incadescent and at 3v, which is a very likely sized current of my layout during a session, I can't see the bulb as it is too dim. But if I use a lower volted bulb I will blow it out when I peak at say around 9-10 volts. Hence the suggestion from Mel to use a voltage limiter or Overmods' suggestion to use a buck booster. Both will give me a consistant voltage to feed the lights, no matter what voltage I use. (thank you Mel and Overmod!)
Really, thanks everyone for your suggestions and I really don't want to polarize this thread (pretty good pun, yeah?).
P.S. Greg, I like reading your posts too!
AblebakercharlieTo me, it seemed very logical that if you are going to do DC and have stand alone block wiring, why would you not want the ability to have multiple trains go in different directions at the same time.
That's true, but I think most of us prefer to be able to independently control two trains at once, rather than just run two via the same throttle but in different directions - like having a train running on the mainline while also doing some switching in a yard with another engine.
BTW I'm still not clear, given what you want to do, why bi-color LEDs wouldn't work? The blocks who's polarity are set one way would make the LED green, the blocks set to the opposite polarity would make them be red.
CSX RobertI believe he did: "I want the ability to have trains be able to go in different directions on different blocks at the same time."
sorry, i missed that
presumably a single throttle is used to control more than one train
so do you want in indication that adjacent blocks are different, or simply the polarity of a block?
wouldn't a single led-resistor across the rails be sufficient? of course they all go off if powered by the track.
greg - Philadelphia & Reading / Reading
Thank you Robert!
Works very good and super simple.Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.