Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

DC Blocks

1517 views
11 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    July 2006
  • From: North Dakota
  • 9,592 posts
Posted by BroadwayLion on Tuesday, January 26, 2016 10:12 AM

LION has complicated wiring. To make Complicated even more obtuse here is plan of LION.

LEFT rail is connected to GROUND. A hard ground that connects through to the building grounding system. Failure to have a good ground at this point will allow stry voltages on what is essentially a floating common, which is not at all the same.

The right rail is divided into blocks by insulated gaps. Put +vdc on the right rail, the train moves forward, put -vdc on the right rail and the train moves in reverse.

The leads from each block go to your selector, where you may select which power pack is controling that segment of track. A SPDT switch with or witout center off will celset between throttle 1 and throttle 2. Interlocking gang switches such as the LION used to use would select between throttles 1 thru 6.

When wiring the power packs put the reversing switch in FORWARD, and TEST it to see which terminal connects to the selector switch and which terminal connects to ground. It really does not matter either way works, just relable the switch as to which way is in fact forward, but here it gets critical, all of your power supplies must be arranged identically otherwise the engine will short the system when it crosses the gap.

Now you layout is not as complicated as anything that the LION would build, so trouble shooting it should be easier. You cannot really use a test lamp as it will tell you the presence of voltage, but not the polarity of the voltage. You need two lamps each preceded by a rectifyer, so that one will light up if + voltage is found and the other will light up if - voltage is found.

If you did not make the LEFT rail ground, as your LION has suggested, any other ground will do. LION has electrical outlets all around the layout of him (this way him needs no extention cords on the floor), and since him used EMT conduit to connect these outlets (and to use as a handle to lift him self up should him be so misguided as to kneel on the floor) Him (or you) could use that conduit as your ground for testing your tracks. + voltage should be on the right rail and - (or zero, if grounded) voltage should be on the left rail assuming your power packs are set to Forward, and are wired correctly. Use your selector to choose between power packs, the position of + and - should not change.

Clear?

It is clear to the LION, but then maybe you are a primate, and are not of felid kind.

 

ROAR

The Route of the Broadway Lion The Largest Subway Layout in North Dakota.

Here there be cats.                                LIONS with CAMERAS

  • Member since
    January 2015
  • From: Southern California
  • 1,682 posts
Posted by Lone Wolf and Santa Fe on Monday, January 25, 2016 9:04 PM

The easiest way to share a picture here is to see it on a website, right click on it, click COPY, then paste it here. (Ctrl+v)

It sounds like the OP is not using an electric train transformer and is just hooking up a power supply to the tracks and using a volume knob. It also sounds like he might have one set of wires reversed.

Modeling a fictional version of California set in the 1990s Lone Wolf and Santa Fe Railroad
  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Monday, January 25, 2016 7:10 PM

I suggested to the OP to read the first post in the General Discussion, Model Railroader forum but suspect it did not work for whatever reason.

Here it is.

http://cs.trains.com/mrr/f/88/t/249194.aspx

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
    January 2009
  • From: Maryland
  • 12,897 posts
Posted by ATLANTIC CENTRAL on Monday, January 25, 2016 6:49 PM

the link is not working for me?

 

    

  • Member since
    October 2005
  • From: Detroit, Michigan
  • 2,284 posts
Posted by Soo Line fan on Monday, January 25, 2016 12:16 PM

Why doesn't the power supply have circuit protection? 

Jim

  • Member since
    December 2015
  • From: Shenandoah Valley
  • 9,094 posts
Posted by BigDaddy on Monday, January 25, 2016 12:10 PM

I never said I saw the drawing.  Newbies have trouble posting pics in all the forums of the Internet.  At least he stayed away from the CAPS LOCK KEY.

A guy that likes wine and trains, deserves a break

Henry

COB Potomac & Northern

Shenandoah Valley

  • Member since
    January 2016
  • 3 posts
Posted by WineNTrains on Monday, January 25, 2016 11:58 AM

Sorry about that.

Here it is.

Wiring

  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Monday, January 25, 2016 11:35 AM

BigDaddy

  If the polarity is the same between blocks, then nothing bad should be happening.  If there is no reversing loop involved, you have made a mistake in wiring. Your rough drawing may show how you think it is wired and not how it is wired.  Get yourself a 12 v bulb connected to a couple aligator clips and do some testing.

 

 

Where is the drawing? Must be a different method that I am not aware of for posting photos.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
    August 2003
  • From: Collinwood, Ohio, USA
  • 16,367 posts
Posted by gmpullman on Monday, January 25, 2016 11:14 AM

Hi,

Read through this and see if the answer lies within.

http://www.nmra.org/beginner/wiring

Are you using common rail? Do you have more than one cab?

The polarity should only change at the power pack (transformer) unless you are including a reverse loop.

Good Luck, Ed

  • Member since
    December 2015
  • From: Shenandoah Valley
  • 9,094 posts
Posted by BigDaddy on Monday, January 25, 2016 11:12 AM

  If the polarity is the same between blocks, then nothing bad should be happening.  If there is no reversing loop involved, you have made a mistake in wiring. Your rough drawing may show how you think it is wired and not how it is wired.  Get yourself a 12 v bulb connected to a couple aligator clips and do some testing.

 

Henry

COB Potomac & Northern

Shenandoah Valley

  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Monday, January 25, 2016 10:52 AM

The picture did not make it here. You need to use a site like photo bucket to post photos here.

You missed the first message in the General Discussion Model Railroader forum.

There is no way to fry a potentiometer that I am aware of. The overload in the DC control should trip first. Mine have a pot controlling a power transistor and circuit breaker after the transistor.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
    January 2016
  • 3 posts
DC Blocks
Posted by WineNTrains on Monday, January 25, 2016 8:12 AM

Hi All,

I'm having problems with blocks. I have 4 blocks on my layout and i have them wired and set to the same polarities and every time I pass an engine over the insulators from one block to another I fry my potentiometer.

Everything has been wired, checked and double checked and I can't figure out why this keeps happening.

Here is a rough wiring diagram that goes to each of the 4 blocks.

Note: the switches are actually SPDT and DPDT switches for power and polarity.

Thoughts??

 

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!