Topics

Non-terminal snubbers


 

I am building a layout with four power districts. Three of the PDs have the power source located centrally, allowing for two track bus of less than 30 feet. I would help to locate the fourth PD such that one track bus would be about 20 feet long and the other about 40 feet long. All of the track bus will have terminal snubbers. Would an additional snubber, located halfway along the 40 foot bus, help to decrease inductance?
Thank you,
Michael


wirefordcc
 

Hi Michael,

Snubbers only go on the end of each run.  If you locate your booster in the middle of a track bus, as you should, you should put a snubber at each end.

Allan Gartner
Wiring for DCC


wirefordcc
 

All,

I talk about snubbers (bus terminators) in my website at:  http://www.wiringfordcc.com/track_2.htm#a47  The information includes where you should put them - at the ends of your buses.

This information is included in the Track Part II section of my website.  An easy way to find the above link is to go to the site map of the website and click on "Snubber" under the "Track" topics.

If you are trying to help someone else, after you find the topic by the above method, you should be able to copy the above link from your browser and send it to them.

Allan Gartner
Wiring For DCC


 

Hi Allan,
Thanks for your response. I am going to twist the track bus wires (three turns per foot) and put snubbers at all the ends. The one longer (40+ feet) bus got me to thinking about an article I read in Model Railroader, May of 2015, by Larry Puckett. In it he says, "try installing snubbers at the ends of each power bus, or even at intermediate points along a power bus." (my emphasis) He also credits Mark Gurries as the "technical advice" for the article, so I tend to give the comment so weight.
Do you think such an intermediate snubber would be of any help?
Thanks,
Michael Boyle


Daniel Brewer
 

Hi Allan,

If my power districts have a single black wire for ground, but up to 4 powered wires which I plan to use for detection (CT Coils using RR-Cirkits products-one red line each for approach, main, siding, approach). Could I have one "common" snubber at the end of the district that ties all lines to it? Does the snubber have any negative effect on detection? None of my bus wires are longer than 40 ft. Sorry for the "elongated" question.
Thx!
Dan


Tim
 

Don't use a snubber on leads with current sensors, it will trip them and look occupied all the time.

Tim Rumph
Lancaster, SC


wirefordcc
 

Hi Dan,

 

One common snubber at the end of the district that ties all the lines to it should work.  Do not put them after the block detector CT (current transformer) coil as you might get a false occupied block.

 

Starting in January, I will be writing the DCC Corner column for Model Railroader.  Can I use your question?  If so, please provide me with your city and state.

 

Thank you

 

Allan


Puckdropper
 

Has anyone tried using the coil-style adjustable block detectors with snubbers? Something like the Team Digital BOD-8?

Puckdropper


Mark Cartwright <marcdecapri@...>
 

Thank you Alan
Your page answered many questions I had not yet begun to know I had.
:)) Mark


Jim Zarnick
 

Congrats Allan!  I subscribe to several HO Facebook groups and when people start asking DCC type wiring question I habitually reference wiringfordcc.com J Looking forward to reading you in MR.

 

I’ve been paying close attention to this dialog as I wonder if my own snubbers are in the right place.  So I’ll ask.

 

I have NCE DCC hardware on the track circuits. (I used to live 2 miles from their shop so I’m loyal, J

 

Layout is multi deck  around the walls with a helix connecting one end of the wall based decks and a platform in the center of the room that connects the 2 decks, allowing continuous running.  Mainline is double and 267 feet long.

 

2 NCE Boosters

12 gauge stranded buses from Boosters. Boosters are wired together for common ground.

5 locations exist around the layout connecting  the buses to 6 NCE Circuit Breakers.

Each circuit breaker is connected to a multi terminal distribution panel like the Micro Structure product.  2 sides 10-12 terminals each side.

My snubbers sit on the bottom of these panels, so 1 snubber per circuit breaker protected district.

From the distro panels after the circuit breaker each block, which have insulation joiners on both rails, have a twisted pair of 18 gauge wire running to them.

One of the block wires runs through an NCE block detector.

Each piece of track has 22 gauge feeders connected the 18 gauge block wires (IDCs everywhere!).

 

So my snubbers are not at the end of runs, as technically the end of my runs are at the end of each block. But my snubbers are before the block detectors.

 

In general I have very few electrical issues but:

1)      I do have the occasional runaway, 

2)      I do have the occasional locomotive that stops and restarts while the other loco in the consist does not, and

3)      I do have an occasional issue with the block detectors not picking up the resistor wheelsets, which is annoying to the signal system and crossing gates.

 

Lots of info here, but welcome knowing if I have my snubbers in the best place?

 

Thanks for the great dialogs in this group!

 

Respectfully,

 

Jim Zarnick

 

 

From: w4dccqa@groups.io [mailto:w4dccqa@groups.io] On Behalf Of wirefordcc
Sent: Saturday, March 14, 2020 10:18 AM
To: w4dccqa@groups.io
Subject: Re: [w4dccqa] Non-terminal snubbers

 

Hi Dan,

 

One common snubber at the end of the district that ties all the lines to it should work.  Do not put them after the block detector CT (current transformer) coil as you might get a false occupied block.

 

Starting in January, I will be writing the DCC Corner column for Model Railroader.  Can I use your question?  If so, please provide me with your city and state.

 

Thank you

 

Allan


Max Maginness
 

The BOD-8 adjustment range is 1.3-7mA
A snubber pulls about 40mA but surely it goes upstream from the detectors - that is closer to the main bus.

Max

-----Original Message-----
From: w4dccqa@groups.io <w4dccqa@groups.io> On Behalf Of Puckdropper via Groups.Io
Sent: Saturday, March 14, 2020 1:27 PM
To: w4dccqa@groups.io
Subject: Re: [w4dccqa] Non-terminal snubbers

Has anyone tried using the coil-style adjustable block detectors with snubbers? Something like the Team Digital BOD-8?

Puckdropper


mgj21932
 

I too look forward to Allen’s column in MR.  I learned so much about DCC from the website that I’m sure we will all benefit from the new column.  
Bill D


On Mar 15, 2020, at 5:03 AM, Jim Zarnick <jameszarnick@...> wrote:



Congrats Allan!  I subscribe to several HO Facebook groups and when people start asking DCC type wiring question I habitually reference wiringfordcc.com J Looking forward to reading you in MR.

 

I’ve been paying close attention to this dialog as I wonder if my own snubbers are in the right place.  So I’ll ask.

 

I have NCE DCC hardware on the track circuits. (I used to live 2 miles from their shop so I’m loyal, J

 

Layout is multi deck  around the walls with a helix connecting one end of the wall based decks and a platform in the center of the room that connects the 2 decks, allowing continuous running.  Mainline is double and 267 feet long.

 

2 NCE Boosters

12 gauge stranded buses from Boosters. Boosters are wired together for common ground.

5 locations exist around the layout connecting  the buses to 6 NCE Circuit Breakers.

Each circuit breaker is connected to a multi terminal distribution panel like the Micro Structure product.  2 sides 10-12 terminals each side.

My snubbers sit on the bottom of these panels, so 1 snubber per circuit breaker protected district.

From the distro panels after the circuit breaker each block, which have insulation joiners on both rails, have a twisted pair of 18 gauge wire running to them.

One of the block wires runs through an NCE block detector.

Each piece of track has 22 gauge feeders connected the 18 gauge block wires (IDCs everywhere!).

 

So my snubbers are not at the end of runs, as technically the end of my runs are at the end of each block. But my snubbers are before the block detectors.

 

In general I have very few electrical issues but:

1)      I do have the occasional runaway, 

2)      I do have the occasional locomotive that stops and restarts while the other loco in the consist does not, and

3)      I do have an occasional issue with the block detectors not picking up the resistor wheelsets, which is annoying to the signal system and crossing gates.

 

Lots of info here, but welcome knowing if I have my snubbers in the best place?

 

Thanks for the great dialogs in this group!

 

Respectfully,

 

Jim Zarnick

 

 

From: w4dccqa@groups.io [mailto:w4dccqa@groups.io] On Behalf Of wirefordcc
Sent: Saturday, March 14, 2020 10:18 AM
To: w4dccqa@groups.io
Subject: Re: [w4dccqa] Non-terminal snubbers

 

Hi Dan,

 

One common snubber at the end of the district that ties all the lines to it should work.  Do not put them after the block detector CT (current transformer) coil as you might get a false occupied block.

 

Starting in January, I will be writing the DCC Corner column for Model Railroader.  Can I use your question?  If so, please provide me with your city and state.

 

Thank you

 

Allan


Don Vollrath
 

Jim, sounds like you have the wiring well in hand.
1. Be sure every loco decoder is set run on DCC only. Not DC.
2. Intermittent pickup on one loco in a consist is annoying. Clean wheels and pickups. Verify no broken internal wiring. Provide track wiring (or common KA device) connections between fixed consist units (?).
3. Wire Snubbers at the input side of occupancy detectors. Not on the wires to track.
4. Test sensitivity of occupancy sensors by using an 8-10K resistor across the track rails. Be sure wheels to resistors on rolling stock are clean. Use a time delay on occupancy release to prevent ‘blinking’.

DonV


Jerry Michels
 

Regarding snubbers and Team Digital BlocD8 current detectors.  We did install snubbers a few years ago, but the always caused the BlocD8's to give a false positive.  We took all the snubbers out, and as far as DCC operation, have not noticed any ill effects.  We have a Digitrax DCC system.

Jerry Michels
Amarillo Railroad Museum


wirefordcc
 

Hi Jim,

 

There is a lot to be said about living down the street from NCE!

 

The snubbers need to be at the ends of your buses.  If you bus leaves in two directions from your booster, you need one at each end.  Your snubbers need to be before your block detectors as they would cause false occupations otherwise.

 

Locos that stop running in a consist may have poor power pick up.

 

Power pick up could also be a problem for your cars that you are relying on for block occupancy.  I moved before I got signaling installed on my last layout.  I’m going to try again in my new home.

 

Can I use your question in my new MR column?  If so, please provide your city and state. 

 

Thank you

 

Allan

Wiring for DCC

 

From: w4dccqa@groups.io <w4dccqa@groups.io> On Behalf Of Jim Zarnick
Sent: Saturday, March 14, 2020 11:29 AM
To: w4dccqa@groups.io
Subject: Re: [w4dccqa] Non-terminal snubbers

 

Congrats Allan!  I subscribe to several HO Facebook groups and when people start asking DCC type wiring question I habitually reference wiringfordcc.com J Looking forward to reading you in MR.

 

I’ve been paying close attention to this dialog as I wonder if my own snubbers are in the right place.  So I’ll ask.

 

I have NCE DCC hardware on the track circuits. (I used to live 2 miles from their shop so I’m loyal, J

 

Layout is multi deck  around the walls with a helix connecting one end of the wall based decks and a platform in the center of the room that connects the 2 decks, allowing continuous running.  Mainline is double and 267 feet long.

 

2 NCE Boosters

12 gauge stranded buses from Boosters. Boosters are wired together for common ground.

5 locations exist around the layout connecting  the buses to 6 NCE Circuit Breakers.

Each circuit breaker is connected to a multi terminal distribution panel like the Micro Structure product.  2 sides 10-12 terminals each side.

My snubbers sit on the bottom of these panels, so 1 snubber per circuit breaker protected district.

From the distro panels after the circuit breaker each block, which have insulation joiners on both rails, have a twisted pair of 18 gauge wire running to them.

One of the block wires runs through an NCE block detector.

Each piece of track has 22 gauge feeders connected the 18 gauge block wires (IDCs everywhere!).

 

So my snubbers are not at the end of runs, as technically the end of my runs are at the end of each block. But my snubbers are before the block detectors.

 

In general I have very few electrical issues but:

  1. I do have the occasional runaway, 
  2. I do have the occasional locomotive that stops and restarts while the other loco in the consist does not, and
  3. I do have an occasional issue with the block detectors not picking up the resistor wheelsets, which is annoying to the signal system and crossing gates.

 

Lots of info here, but welcome knowing if I have my snubbers in the best place?

 

Thanks for the great dialogs in this group!

 

Respectfully,

 

Jim Zarnick

 

 

From: w4dccqa@groups.io [mailto:w4dccqa@groups.io] On Behalf Of wirefordcc
Sent: Saturday, March 14, 2020 10:18 AM
To: w4dccqa@groups.io
Subject: Re: [w4dccqa] Non-terminal snubbers

 

Hi Dan,

 

One common snubber at the end of the district that ties all the lines to it should work.  Do not put them after the block detector CT (current transformer) coil as you might get a false occupied block.

 

Starting in January, I will be writing the DCC Corner column for Model Railroader.  Can I use your question?  If so, please provide me with your city and state.

 

Thank you

 

Allan


Daniel Brewer
 
Edited

Hi Allan,

I've added a .pdf of the two wiring schemes I've considered to the Files/Non-terminal snubbers Thread. As I'm coming to understand, I think example one is the wrong one to use if I need snubbers, and also need detection. Please comment as warranted.

Dan
Granger, IN


wirefordcc
 

Hi Daniel,

You can put a snubber at the end of your undetected track.  You can't put a snubber after a block detector as it will likely give a false occupied signal all the time.

As I build my new railroad, I am planning to run a booster district about 23 feet in each direction from the booster. I will twist these wires and put snubbers at each end.  Along the way, I will have short sub buses that will have block detectors.  These sub buses will not be twisted or have snubbers.

Allan Gartner
Wiring for DCC


mgj21932
 

Allen,

Is there a reason for not twisting the sub-bus wires?  

I am planning a similar wiring pattern with a "N/S" main bus (twisted wires) and several "E/W" sub busses off the main bus.  I had planned to twist the sub-bus wires as well (until now).  

Given relatively short length of all buses, I was not planning on any snubbers.  Do you recommend omitting snubbers if all runs are less than 15 feet?

Bill D

On Monday, March 16, 2020, 10:29:14 AM EDT, wirefordcc <bigboy@...> wrote:


Hi Daniel,

You can put a snubber at the end of your undetected track.  You can't put a snubber after a block detector as it will likely give a false occupied signal all the time.

As I build my new railroad, I am planning to run a booster district about 23 feet in each direction from the booster. I will twist these wires and put snubbers at each end.  Along the way, I will have short sub buses that will have block detectors.  These sub buses will not be twisted or have snubbers.

Allan Gartner
Wiring for DCC


wirefordcc
 

Bill,

I figure you are trying to tell me something by your use of E/W and N/S busses.  I think if sub buses running in the same direction as your main bus, but being attached to one another with the intention of breaking up the main bus into sections to create blocks for block detection or electronic circuit breaker districts.

You don't want to twist your sub buses after block detectors because the twisting could cause false occupation indications.  You don't want to put snubbers after block detectors for the same reason.  Note:  Someone contributed to my website that twisting could come after a block detector if a capacitor is used.  I haven't tried that myself yet to see if it always works or not.  Let me know if you try it and it works for you.

Just in case anyone is wondering about Frog Juicers, don't put them after block detectors, either.  See the section on block detection in my website for more information.  BTW, I like Frog Juicers.  I have many of them.

http://www.wiringfordcc.com/blockdet.htm

FYI to all:  I have moved and am building a new railroad in which I will be installing block detection and at some point, signaling.  I'm going as fast as I can, but I have a long way to go.  Also, with the stock market crashing, I'm not spending money as freely on the railroad as I had been doing before.  Block detection may only be installed on a limited section of the railroad as a test section.

Allan Gartner
Wiring for DCC


mgj21932
 

Allen,

Sorry for confusion.  Was using "N/S" simply to indicate the "main" bus running down the middle of the layout parallel to the longest side (acting as a "spine"), and "E/W" to describe power bus "spurs" coming off the spine.  At this point I am not planning on occupancy detectors.   

Actually the 14 AWG main bus will be split at a centrally located Tam Valley Hex Juicer (being used as a AR switch), with the main bus powering the mainline (no AR) and two sub-buses running downstream from the Hex Juicer to provide track power to two AR segments.  TV circuit breaker is located upstream from Hex Juicer close to power supply.  

Outputs from Hex Juicer are short 22 AWG stub wires connected to 14 AWG power sub-buses.  I was planning to twist wires on all the power buses and use 22 AWG for track feeders.  Did not plan on using snubbers (or at this point occupancy detectors).  

With no wires longer than 12 feet or so, I didn't think I needed snubbers.  Is that a valid assumption?  

Plus I planned to twist the sub-bus wires downstream from the Hex Juicer.  Any reason not to do so?

Based on your previous reply, would the reason for not twisting those wires be to make later installation of occupancy detectors easier?

Bill D   

On Monday, March 16, 2020, 02:39:29 PM EDT, wirefordcc <bigboy@...> wrote:

Bill,

I figure you are trying to tell me something by your use of E/W and N/S busses.  I think if sub buses running in the same direction as your main bus, but being attached to one another with the intention of breaking up the main bus into sections to create blocks for block detection or electronic circuit breaker districts.

You don't want to twist your sub buses after block detectors because the twisting could cause false occupation indications.  You don't want to put snubbers after block detectors for the same reason.  Note:  Someone contributed to my website that twisting could come after a block detector if a capacitor is used.  I haven't tried that myself yet to see if it always works or not.  Let me know if you try it and it works for you.

Just in case anyone is wondering about Frog Juicers, don't put them after block detectors, either.  See the section on block detection in my website for more information.  BTW, I like Frog Juicers.  I have many of them.

http://www.wiringfordcc.com/blockdet.htm

FYI to all:  I have moved and am building a new railroad in which I will be installing block detection and at some point, signaling.  I'm going as fast as I can, but I have a long way to go.  Also, with the stock market crashing, I'm not spending money as freely on the railroad as I had been doing before.  Block detection may only be installed on a limited section of the railroad as a test section.

Allan Gartner
Wiring for DCC