Date   
Re: Auto Reversing circuit rail gaps

Douglas Krahn
 

I believe I read somewhere that the two gaps should be staggered by 1/8 inch..

Doug


On Tuesday, March 3, 2015 9:13 AM, "lee.hanna60@... [WiringForDCC]"


 
This may have been addressed before, so please forgive me if it has.  Do the rail gaps that separate a section controlled by an auto reverse circuit have to be opposite each other, or can they be offset?

Thanks much in advance.

Lee


Re: Auto Reversing circuit rail gaps

Vollrath, Don <dvollrath@...>
 

The insulating gaps can be directly opposite or offset. It doesn’t make any difference. If the polarity needs correcting, the short circuit created on either rail, or even both rails simultaneously, will be detected and trigger the A-R unit to fix the rail polarity problem… on both rails. After it is corrected, there will be no problem at the location of a later spaced gap crossing at the same end of the A-R section.

 

DonV

 

From: WiringForDCC@... [mailto:WiringForDCC@...]
Sent: Monday, March 02, 2015 8:58 PM
To: WiringForDCC@...
Subject: [WiringForDCC] Auto Reversing circuit rail gaps

 




This may have been addressed before, so please forgive me if it has.  Do the rail gaps that separate a section controlled by an auto reverse circuit have to be opposite each other, or can they be offset?

 

Thanks much in advance.


Lee




Re: Auto Reversing circuit rail gaps

Ross Kudlick
 

Lee,

 

I suggest checking the instructions for the specific auto-reverser you are using.

 

I am partial to the DCC Specialties PSX-AR; the instruction manual (page 9) says:

“When setting up gaps for reverse sections, we recommended that the gaps be staggered about 1/8 “. Perfectly aligned gaps may reduce the current needed for PSX-AR to reverse properly.”

We have installed them where “directly opposite” gaps pre-existed without difficulty; where new gaps were required we have off-set them.

 

http://www.dccspecialties.com/products/pdf/man_psxar.pdf

 

YMMV

Regards,

Ross Kudlick

 

From: WiringForDCC@... [mailto:WiringForDCC@...]
Sent: Monday, March 02, 2015 9:58 PM
To: WiringForDCC@...
Subject: [WiringForDCC] Auto Reversing circuit rail gaps

 

 

This may have been addressed before, so please forgive me if it has.  Do the rail gaps that separate a section controlled by an auto reverse circuit have to be opposite each other, or can they be offset?

 

Thanks much in advance.


Lee

Re: Auto Reversing circuit rail gaps

Dale Gloer
 

Bruce Petrarca, who has a lot of DCC experience, recommends that the gaps be offset by a small amount, maybe 2 or 3 tie spaces.  This is to prevent the auto reverser from being confused by nearly simultaneous inputs if the gaps are exactly opposite each other.

Dale Gloer

Auto Reversing circuit rail gaps

Lee Hanna
 

This may have been addressed before, so please forgive me if it has.  Do the rail gaps that separate a section controlled by an auto reverse circuit have to be opposite each other, or can they be offset?


Thanks much in advance.


Lee

Re: Separation Between Reverse Loop and HARE "Trigger Rails"

dvollrath@...
 

Oops... After reading the diagram again, the official answer is that you need a small section of fixed polarity track to separate the trigger rails of the Hare from the auto-reversing section.

But I wonder if that can be circumvented by powering the Hare from the A-R tracks instead of fixed polarity mains. Might be worth a try. I don't have any of these gadgets to play with.

DonV

  • 0 Attachment




    Re: DCC Interior Coach Lighting - Need A SIMPLE Circuit

    wirefordcc
     


    Here is a "simplist of circuits" for constant lighting.  It contains the LM317 that Len mentions.  There are several circuits shown.  You will need to scroll down to the fourth circuit using LEDs.


    http://www.wiringfordcc.com/gorhlite.htm#a17


    Allan Gartner

    Wiring For DCC


    Re: DCC Interior Coach Lighting - Need A SIMPLE Circuit

    jazzmanlj
     

    Some diodes such as UF4001 for rectifiers and 3 terminal regulator with input and output caps. My preference is the LM317 which is adjustable for output.


    Len Jaskiewicz

    Re: DCC Interior Coach Lighting - Need A SIMPLE Circuit

    george hohon3
     

    Very detailed and well presented, thanks.

    Hoot


    On Feb 28, 2015, at 8:20 PM, "Thomas Stephens deerpen4@... [WiringForDCC]" <WiringForDCC@...> wrote:

     

    Hoot
    Here is one solution:
    Tom



    From: "george hohon3 hohon3@... [WiringForDCC]" <WiringForDCC@...>
    To: "WiringForDCC@..." <wiringfordcc@...>
    Sent: Saturday, February 28, 2015 5:22 PM
    Subject: [WiringForDCC] DCC Interior Coach Lighting - Need A SIMPLE Circuit

     
    Can anyone provide suggestions, recommendations or links to the simplest of circuits for providing a "flicker-free" lighting circuit for LEDs for the purpose of lighting interior coach spaces, made from readily available parts, from an easy to reach supplier?  A definitive parts list would also be appreciated.  Thanks in advance.

    Hoot Gibson


    Re: DCC Peak Voltages and TVS Diodes

    mikea442
     

    The most notable decoders that fail on me are older TCS T1's. I also have many NCE D13SR's with no issues. I do not notice after a short, but I do notice the problem happens more when I start up system for running. What worked yesterday, doesn't work today.

    Mike

    Re: DCC Peak Voltages and TVS Diodes

    mikea442
     

    I do not have any sound decoders, but I do have older TCS T1's which as I mentioned are the most frequent culprits. Also have numerous NCE D13SR's with no problems.

    Mike

    Re: DCC Interior Coach Lighting - Need A SIMPLE Circuit

    Thomas
     

    Hoot
    Here is one solution:
    Tom



    From: "george hohon3 hohon3@... [WiringForDCC]"
    To: "WiringForDCC@..."
    Sent: Saturday, February 28, 2015 5:22 PM
    Subject: [WiringForDCC] DCC Interior Coach Lighting - Need A SIMPLE Circuit

     
    Can anyone provide suggestions, recommendations or links to the simplest of circuits for providing a "flicker-free" lighting circuit for LEDs for the purpose of lighting interior coach spaces, made from readily available parts, from an easy to reach supplier?  A definitive parts list would also be appreciated.  Thanks in advance.

    Hoot Gibson


    DCC Interior Coach Lighting - Need A SIMPLE Circuit

    george hohon3
     

    Can anyone provide suggestions, recommendations or links to the simplest of circuits for providing a "flicker-free" lighting circuit for LEDs for the purpose of lighting interior coach spaces, made from readily available parts, from an easy to reach supplier?  A definitive parts list would also be appreciated.  Thanks in advance.

    Hoot Gibson

    Re: Separation Between Reverse Loop and HARE "Trigger Rails"

    dvollrath@...
     

    Yes, the trigger rails can be adjacent to the auto-reverse loop tracks . See http://dccspecialties.com/products/pdf/man-hareng.pdf page 6

    DonV

    Re: DCC Peak Voltages and TVS Diodes

    dvollrath@...
     

    Early versions of Tsunami would sometimes drop out the consist number. About the only thing could blame it on was a short time pick-up drop-out as it always seemed to happen as the loco crossed through a turnout with a very quick headlight blink. Adding 10 uF between the blue wire (+) and the negative rectified bus seems to have cured it.

    DonV 

    Re: DCC Peak Voltages and TVS Diodes

    Paul O
     

    Mike, fwiw, the only decoders I ever have the ‘loosing address’ problem with are the TCS-T1’s.

    Doesn’t happen that often, but when it does, it’s always after a derailment that causes a short.

    Reading the resultant address on the program track shows no pattern of dropped/picked-up bits after that happens.

     

    Paul O

    Re: DCC Peak Voltages and TVS Diodes

    mikea442
     

    Thanks for the reply. I will make note of the decoders involved, try to add Zener diodes and research capacitor idea.

    Some of my locos have my own design Keep A Live type capacitors (as long as decoder has a good ground point to attach to), but it did not appear that these had any issues.

    I do recall that a few of the decoders that lost CV's were older type T1's.

    Thanks again

    On 2/28/2015 1:32 PM, dvollrath@... [WiringForDCC] wrote:
     

    Mike, I understand your observations, situation and fears.The issue of decoders losing their brains is related more to poor decoder design than the voltage peaking you are measuring. Voltage ringing and peaking is related to the fast DCC voltage reversals from your booster and the effects of 'open circuit' wiring under the conditions of no load being attached. Yes, snubbers/filters/R-C circuits (take your pick for a name) will suppress that, but normally that in itself does no damage. The real problem is how the decoder reacts to intermittent loss of power from its own pick-up wheels or what happens when a sparking short appears somewhere else on the layout. That too will cause a splash of power off/on cycles to any nearby decoder.  A secondary effect of a sparking short circuit is energy kick-back from wiring inductance, which can cause a much larger voltage spike and real damage to seemingly unrelated equipment attached to those same wires and track.

    Here are some things that help:

    1. Add a snubber inside the loco. This could alternately be a TVS or zener diode on the DC side of the power rectifier of the decoder. The purpose is to gobble up inductive energy spikes and prevent it from causing mayhem. A 30V 1/2 W zener is enough for HO or S scale.

    2. Add a 10-20 microfarad carry-over cap to the decoder in the loco. This not only absorbs inductive kick-back energy, but also keeps the internal microprocessor powered during short term wheel pick-up interruptions so that the uP doesn't get confused and somehow overwrite CV memory. This is not the same as the 'keep alive' caps and circuits as they have charging current limiters and cannot absorb energy quick enough to protect an encoder from overvoltage transients.

    3. Note what brand of decoders exhibit the problem... Don't buy them again.


    DonV


    Re: dcc and dc power

    andymsa2
     

    hi thanks for the replies, no they are not mains cables. so will now start to install the power buses

    Re: dcc and dc power

    dvollrath@...
     

    Should be no problem at all. However hopefully you are not talking about 120V AC mains power. This is a totally different safety issue and should be avoided.

    DonV

    Re: DCC Peak Voltages and TVS Diodes

    dvollrath@...
     

    Mike, I understand your observations, situation and fears.The issue of decoders losing their brains is related more to poor decoder design than the voltage peaking you are measuring. Voltage ringing and peaking is related to the fast DCC voltage reversals from your booster and the effects of 'open circuit' wiring under the conditions of no load being attached. Yes, snubbers/filters/R-C circuits (take your pick for a name) will suppress that, but normally that in itself does no damage. The real problem is how the decoder reacts to intermittent loss of power from its own pick-up wheels or what happens when a sparking short appears somewhere else on the layout. That too will cause a splash of power off/on cycles to any nearby decoder.  A secondary effect of a sparking short circuit is energy kick-back from wiring inductance, which can cause a much larger voltage spike and real damage to seemingly unrelated equipment attached to those same wires and track.

    Here are some things that help:

    1. Add a snubber inside the loco. This could alternately be a TVS or zener diode on the DC side of the power rectifier of the decoder. The purpose is to gobble up inductive energy spikes and prevent it from causing mayhem. A 30V 1/2 W zener is enough for HO or S scale.

    2. Add a 10-20 microfarad carry-over cap to the decoder in the loco. This not only absorbs inductive kick-back energy, but also keeps the internal microprocessor powered during short term wheel pick-up interruptions so that the uP doesn't get confused and somehow overwrite CV memory. This is not the same as the 'keep alive' caps and circuits as they have charging current limiters and cannot absorb energy quick enough to protect an encoder from overvoltage transients.

    3. Note what brand of decoders exhibit the problem... Don't buy them again.


    DonV