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Preventing DCC Shorts: Ugh again!

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Preventing DCC Shorts: Ugh again!
Posted by kasskaboose on Wednesday, April 29, 2020 3:27 PM

Not seeking on reviving a dead horse, but can anyone kindly offer a suitable way to prevent a short in DCC (besides being more careful not leaving anything metal on the track). I get the frustration!

I read the discussion here debating the value of creating our own circuit breaker using auto bulbs as mentioned in the June 2017 MR article. The consensus was the homemade breaker wasn't viable for most. I knew NCE makes a similar one for $30 bucks, which would work with my NCE Starter DCC system. Should I use their product or just be more careful? My HO layout is 14x10 E-shaped design with a 10x5 peninsula.

Thanks!

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Posted by jjdamnit on Wednesday, April 29, 2020 3:46 PM

Hello All,

kasskaboose
...can anyone kindly offer a suitable way to prevent a short in DCC(.)

What is causing these shorts in the first place?

  • Motive power or rolling stock with metal wheels jumping the track or derailing (track work)?
  • Curves that are too small for motive power or rolling stock to negotiate; 15-inch curves with 6-axle locos or 89-foot passenger cars (oversized locos or rolling stock)?
  • Metal coupler trip pins sagging and shorting over frogs (coupler maintenance)?

Installing circuit protection will only mask the problems and not solve them.

Recently, after upgrading 24 vintage cars from plastic wheels and metal-framed trucks and hardware to plastic trucks and hardware with metal wheels (0.110") I discovered that the treads of the new wheels were too wide and causing shorts over the dead frogs.

The solution was to replace all the wheelsets to semi-scale (0.088").

Correcting the reason(s) for the shorts is better in the long run.

Hope this helps.

 

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by cuyama on Wednesday, April 29, 2020 4:04 PM

kasskaboose
besides being more careful not leaving anything metal on the track

Start there.

kasskaboose
creating our own circuit breaker using auto bulbs as mentioned in the June 2017 MR article

That's not a circuit breaker. It's a circuit limiter. Similar function in some ways, but not every way.

kasskaboose
Should I use their product or just be more careful?

A couple of these seem like cheap protection if you can't discipline yourself to stop leaving junk on the track.

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Posted by gregc on Wednesday, April 29, 2020 4:33 PM

kasskaboose
I knew NCE makes a similar one for $30 bucks, which would work with my NCE Starter DCC system. Should I use their product or just be more careful?

if by NCE Starter system you mean the PowerCab, the PowerCab will of course shut down and restart when a short occurs, but takes several seconds.   This makes it difficult to track down intermittent shorts.

the PowerCab doesn't draw enough current for the 1156 bulb to operate, but I found and use a T3 bulb which draws enough current (~1A) to limit the short circuit current without causing the PowerCab to shut down.   This means the bulb turns off immediately when any short is cleared and the PowerCab continues without interruption

greg - Philadelphia & Reading / Reading

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Posted by RR_Mel on Wednesday, April 29, 2020 4:47 PM

A circuit breaker or a automotive light bulb will not prevent a short circuit!!!!  The layout operator has to prevent shorts from happening.  You have to make sure everything is working correctly to prevent shorts!  All the circuit breakers you could manage to install will not prevent shorts.
 
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by jjdamnit on Wednesday, April 29, 2020 4:56 PM

Hello All,

RR_Mel
A circuit breaker or a automotive light bulb will not prevent a short circuit!!!! The layout operator has to prevent shorts from happening. You have to make sure everything is working correctly to prevent shorts! All the circuit breakers you could manage to install will not prevent shorts.

YES!

Thank you for your supporting position!!!

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by cuyama on Wednesday, April 29, 2020 5:15 PM

jjdamnit
What is causing these shorts in the first place?

The original poster said it was because he was leaving metal objects on the track.

kasskaboose
prevent a short in DCC (besides being more careful not leaving anything metal on the track)

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Posted by rrinker on Wednesday, April 29, 2020 5:32 PM

 The EB-1 will likely not work with JUST the basic PowerCab - the trip current is too high and the PowerCab will shut down before the EB-1 does. The only option NCE has for the PowerCab is the CP-6, which is just the light bulb thing on a nice circuit board with terminals to attach the wires.

 The PSX1 from DCC Specialities has an option to work with low power systems like the PowerCab.

 If you also have the SB5 added to your PowerCab system, the EB-1 will work fine.

                                            --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by kasskaboose on Wednesday, April 29, 2020 8:39 PM

All,

Thanks for the helpful suggestions.  I have no idea what caused the shorts.  It is quite frustrating having them arise.  It seems that the solution is going slowly with wiring and scenery to ensure nothing causes a short. 

All:  How to create a way that if a short occurs in one area of the layout, it doesn't cause the entire system to stop functioning? Is the CP-6 what I need to do that or use what a youtuber suggested with the auto bulbs?  The guy indicated that both are interchangeable.  Here's the vid:

https://www.youtube.com/watch?v=6e6IecGiNtM

 

 

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Posted by mbinsewi on Wednesday, April 29, 2020 9:11 PM

RR_Mel
A circuit breaker or a automotive light bulb will not prevent a short circuit!!!!  The layout operator has to prevent shorts from happening.  You have to make sure everything is working correctly to prevent shorts!  All the circuit breakers you could manage to install will not prevent shorts.

Agreed!  Just what is the problem, that you are getting shorts?  The only shorts I ever get is the self-induced shorts when I place the quarter on the rails to test my old DB150, to make sure it works.

I don't have any circuit breakers, other than what the DB150 gives me.

Just what is your particular problem?

Mike.

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Posted by ba&prr on Wednesday, April 29, 2020 9:59 PM

You need to divide your layout into power districts and use DCC Specialties PSXx circut breakers. The October 2017 MR had an article on how to do it. If you have power districts, a short in 1 will not shut the whole layout down.   Joe

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Posted by selector on Thursday, April 30, 2020 2:26 AM

Prevention is always Job One.

I would undertake the process of running the most troublesome locomotive and marking where it stops, because that's what it will do as soon as a short occurs. Then, remove the power ASAP and remove the locomotive.  

After a close visual inspection, and finding no small filaments of metal bridging rails, especially nearest the frog on a turnout, or an errant screw, or a metal tool left across the rails, I would suspect the locomotive wheels.  They might be bridging at the frog, specifically at the closure rails or at the frog point rails.  Curved turnouts are the worst, but it can happen at regular turnouts.  You'll have to cut a gap further out on one of the two frog rails, or use the time-proven method of painting one of the rails near the plastic insulator with clear nail polish.  About once every two months if you're lucky.

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Posted by BigDaddy on Thursday, April 30, 2020 6:39 AM

Short circuits don't fall from the skies.   I think the OP was joking about leaving stuff on the track, but all of us have done that at least once.  If it's a recurrent problem, then the the OP needs to have a pre flight list to check the track before running trains.

The other place shorts come from are derailments.  Is it specific to a loco or an area of track.   Circuit breakers and light bulbs don't fix bad track work or out of spec wheel sets.

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by MisterBeasley on Thursday, April 30, 2020 10:03 AM

Circuit breakers protect your electronics when there is a short, but no circuit breaker will prevent you from having shorts.  Those must be dealt with individually.  There can be many different causes, so keep looking.

Multiple districts with individual breakers will help you isolate the problems.

When you expand or upgrade you layout, do it one small section at a time, and test each section rigorously before going on to the next.  It's much easier to find a problem when you know it's probably in the thing you just did.

It takes an iron man to play with a toy iron horse. 

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Posted by selector on Thursday, April 30, 2020 11:21 AM

As he is sure to do, Mr. B brings up a good point.  If you run into trouble and have to undo your last three or four wiring steps, but one at a time in case you find it with the first or second undoing, why not build the electron distrubution the same way?  One step at a time.  Solder a pair of feeders, run a loco.  Solder the next pair...run the loco.  That way, if you make a mistake, it'll turn up the instant you apply power through the wires.

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Posted by kasskaboose on Thursday, April 30, 2020 1:44 PM

VERY helpful advice everyone.  Thank you so much.  Yes, I've fallen in the trap of having something small get placed on the track to shut down the entire layout.  Slow progress makes sense.  I ALWAYS test as I go with wiring and a klutzy thing caused this latest short.

The good news is there's really nothing to purchase. Being more mindful and preparing a checklist is essential.  DCC def has it's learning curve, which includes steady hands.

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