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Shorting Out

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  • Member since
    November 2007
  • From: Northern Michigan
  • 100 posts
Shorting Out
Posted by BNENGR on Tuesday, February 19, 2008 12:48 AM

Hi Group,

In a recent post I mentioned I was having trouble with a new section of track that I had added on my layout. My HO scale 20x30 (formerly DC with block control) newly transformed to DCC with a Digitrax Super Chief layout with a 8' x 10' extension. The problem was and still is a short that occurs between the old sections and the new sections whenever a loco crosses the gaps. Both sides of the new section are gapped and I've run feeders from the new section to my bus wires. I completely disconnected this section from the original block control switch on the control panel (trying to solve the mystery) and ran feeders from the old section of track to the new DCC bus wires also. I'm ready to pull the remaining hair I have left trying to figure this out! I've tried changing the polarity which solves the problem on one side of the layout but not on the other side. I've also tried a PSX-AR (auto-reverser) thinking it could be a reverse loop and that failed also. All the other blocks on the layout work fine. I throw the switches on the block control panel all one way and have those cab wires running to the DCC bus wires. Works great except for the one block. Any ideas will be greatly appreciated!

Thank you.

Paulie

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  • Member since
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  • From: Central Georgia
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Posted by Johnnny_reb on Tuesday, February 19, 2008 1:19 AM

in an order to help us understand your problum please post a drawing of the track and wiring. as in most things I understand that you have added a new section to your layout. unwire this section and see if the short goes away. if it does the short is in your wiring of this new section or the new track, but without seeing this your guess is as good as any.

Johnnny_reb Once a word is spoken it can not be unspoken!

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Posted by 60YOKID on Tuesday, February 19, 2008 6:33 AM

Just make sure each section is isolated twice, once on either end, then feed the power to that entire section through the reverser.  It sounds like you have already done this. 

One thing you could check is the adjustable short circuit range on the reverser.  The PSX-AR is adjustable, but factory set at 3.81 amps.  If your power supply puts out less than that, the circuit breaker in the reverser may not trip on a short.  If your power supply is less than 5 amps you could consider an upgrade.  This could also limit the current necessary to cause the reverser to trip.

In addition, I think there is a jumper you can use to enable additional inrush current so the PSX-AR reverser can actually switch over.  You can get the info online at Tony's website links.

Just my 2cents at 6:00 AM 

-Bill 

  • Member since
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  • From: Central Georgia
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Posted by Johnnny_reb on Tuesday, February 19, 2008 8:59 AM

I reiterate without seeing the track arrangement of your "new" section as it relates with the "old" section I can not tell if it "IS" a reversing section. Please post a drawing of said track and wiring. 

Other wise it is all a guessing game as to what is wrong.

Guess#1. You got the while thing wet and it shorted out everything.

Guess#2. All of your wires have melted together shorting the whole layout out.

Guess#3. You poured a cup of coffee into the main control panel shorting them out.

Guess#4. .................................Clown [:o)]

Johnnny_reb Once a word is spoken it can not be unspoken!

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Posted by BNENGR on Tuesday, February 19, 2008 4:48 PM
Hi again Group. Here's a drawing of the track section that's giving me a problem with shorting out. Please excuse the cave man drawing! Thanks, Paulie
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Posted by Vail and Southwestern RR on Tuesday, February 19, 2008 5:00 PM

Yep, you have a reverse loop!  Put your finger on the plan, above the turnout, and trace all the way around the new section, and you come out of the turnout going the other way.  So, put the reverse loop controller in the new section, between the double gaps, including the yard, and everything should work fine.

 

Jeff But it's a dry heat!

  • Member since
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  • From: Gahanna, Ohio
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Posted by jbinkley60 on Tuesday, February 19, 2008 5:03 PM

 BNENGR wrote:
Hi again Group. Here's a drawing of the track section that's giving me a problem with shorting out. Please excuse the cave man drawing! Thanks, Paulie

You've created a reversing section with the new addition.  You will need the PS-AR.  Try this and see what happens:

1.  Remove all locomotives from the new section.
2.  Remove all power feeds to the new section so that it is a stand-alone block
3.  Connect the PSX-AR output to the new section
4.  Try running locomotive between sections again
5.  If you get a short, not whether the protection on the old section or the new section shows the short

A couple of other questions.  What type of short circuit protection is on the old section ?  Is that the entire old section track plan or is there more ?  If there is more, please post the entire diagram, of problems persist.

 

Engineer Jeff NS Nut
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Posted by Johnnny_reb on Wednesday, February 20, 2008 12:11 AM

Yes you have made a reversing loop. Now with that said, if you would take the turnout on the right side, replace it with a left hand turnout and turn it half way around you would elimate the reversing section making it a loop track and the old section in the upper right would then be a spur line.

But as is, the reversing section is the new section only. If you make the new section isolated and wirer it as a reversing section and leave the old section alone the system should be fine.

IE make the new section a new block by itself and install an auto reverser into it and only it. This should fix your problem.

Johnnny_reb Once a word is spoken it can not be unspoken!

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Posted by Johnnny_reb on Wednesday, February 20, 2008 7:49 AM

Supplement to my first post

 BNENGR wrote:
Hi again Group. Here's a drawing of the track section that's giving me a problem with shorting out. Please excuse the cave man drawing!

Thanks, Paulie

The Digitrax Super Chief DCC system should have enough power to trip the auto-reverse. The auto-reverse needs to be installed into the "NEW" section wiring.

Make the old section and the new section separate blocks.

IE block one is the old section and block two is the new section with the auto-reverse installed.

If you have the whole layout as one block it will not work!

The reversing section MUST be by itself. It must be isolated! in order to work.

If you have the auto-reverse wired into the layout as one block it will not work! The layout as you have drawn it MUST be two separate blocks in order to use an auto-reverse unit.

**HOLD THAT THOUGHT**

instead of one auto-reverse unit you need two. 

As you drive into the new section on the right side the auto-reverse trips to match the polarity but as you drive out of the new section on the left back into the old section you need a second auto-reverse unit to trip to match the polarity at this end of the track also.

                 ------<------<------<

==== + gap + ==== - gap - ======

the auto-reverse trips matching the polarity as you enter the new section

at the exit end the polarity is wrong

the second auto-reverse trips as you exit the other end

===== - gap - ====== + gap + ======

matching the polarity as you cross the gap and re-enter the old section.

You have been doing it right just missing one piece of the puzzle.

"I see said the blindman"

As I designed a layout with just this problem and have been talking to a man that deals in DCC but have not gone into depth about it I do not know exactly how to wire this up, although after thinking on your post I now understand the need for two auto-reverse units and how it would work. ( reaches for a cold towel (as my head hurts)).Sigh [sigh]

Johnnny_reb Once a word is spoken it can not be unspoken!

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Posted by CSX Robert on Wednesday, February 20, 2008 9:01 AM
BNENGR,

You do not need two auto-reverse units. What kind of turnout do you have between the old section and the new section? Some power routing turnouts cause the polarity on the two rails that the turnout is not aligned for to be the same. If the auto-reverser did not work, it sounds like that is the type of turnout you have. If that is the case, when you have the auto-reverse unit wired up, you will be able cross the insulated gaps closer to the turnout leg that the turnout is aligned for with no problem because the auto-reverser will switch the polarity to match that leg, but when you cross the other gap, it will cause a short through the other leg of the turnout.
  • Member since
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Posted by floridaflyer on Wednesday, February 20, 2008 9:29 AM

Could you move the insulating cuts you made  by the right hand turnout to the divergent track at the same turnout, thus taking the turnout out of the problem. Then hook the reverser to the old section between the insulating cuts on the left side of the layout and the new insulation cuts on the divergent track by the right hand turnout.this would make the reversing section a seperate block in the old section of the layout. at any rate,I agree with CSX, you only need one reverser. 

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