# DCC circuit breaker tripping???



## flyerrich (Feb 17, 2014)

Using an NCE Power cab and I have the DCC specialties circuit breaker board installed. Everything seems to work fine except no matter if I am running one or more locos all is well then the short circuit light flashes, track loses power the breaker resets and loco starts back up. May run a foot, four feet or more then it happens again. This happens no matter what loco/locos I am running. Then it may be fine for a long time and then for no apparent reason that I can find it will happen again. Anyone have any ideas on what I might look for as a reason???
Thanks


----------



## Brakeman Jake (Mar 8, 2009)

First,your locos may be pulling too much power.Specially if they're older models retrofitted to DCC,they may need re-motoring.Not likely with newer models.

There may indeed be occasional shorts on the layout.If it happens in the same area every time,that would raise suspicion.

If the breaker is adjustable,it may be set too low.

The breaker may be defective...not likely but possible.

I believe your NCE set has an ammeter feature.A normal draw for a loco (HO) should be around .4 to .7 amps,not exceeding one amp.


----------



## tr1 (Mar 9, 2013)

*Intermittant power loss/ & short circuit*



flyerrich said:


> Using an NCE Power cab and I have the DCC specialties circuit breaker board installed. Everything seems to work fine except no matter if I am running one or more locos all is well then the short circuit light flashes, track loses power the breaker resets and loco starts back up. May run a foot, four feet or more then it happens again. This happens no matter what loco/locos I am running. Then it may be fine for a long time and then for no apparent reason that I can find it will happen again. Anyone have any ideas on what I might look for as a reason???
> Thanks


 From my exhaustive research It sounds like you may have one or two problems either your drop wires are two long/and or the wire gauge
is two small I would recommend you reference Brian Gartners web sight on DCC wiring. Good luck with this now!
Regards,tr1


----------



## gregc (Apr 25, 2015)

the PowerCab will shut down if its current limit is exceeded. (I use lamps)

what happens if you bypass the circuit breaker? If things work fine without it, the issue is with the circuit breaker.

if there's still a problem, then its with the loco

i don't understand how wire length or gauge can cause a short. If anything, they would reduce the chance by restricting current.


----------



## D&J Railroad (Oct 4, 2013)

The circuit breaker board also has a feature to adjust how fast the breaker reacts to a short. It may be set to react to quick. Check the setup instructions and you will find it.
As far as gauge of wire effecting the circuit breaker, two small a gauge will trip it because more current is flowing than the wire can support without overheating. Circuit breakers trip due to heat from the rush of current. If you're using old phone line wires to run 20' of so on your layout, you're overloading your breaker system.


----------



## gregc (Apr 25, 2015)

D&J Railroad said:


> As far as gauge of wire effecting the circuit breaker, two small a gauge will trip it because more current is flowing than the wire can support without overheating. Circuit breakers trip due to heat from the rush of current.


wires can only add resistance to the circuit and reduce the current. The comment seems to suggest that the overheated wires reduce the resistance of the circuit (i.e subtract from the resistance in the motor).

"in rush" current is due to large capacitance that draws higher current until charged or possibly until the motor starts turning. Don't understand how feed wires can cause a short in the ways described.


----------



## Brakeman Jake (Mar 8, 2009)

Too small wires will waste current through heat thus raising the consumption of the powered component.


----------



## Lemonhawk (Sep 24, 2013)

Its unlikely that adding resistance in series with the locomotive which higher gauge wire would be, could ever cause more current to flow - just can't happen. The circuit breakers should be adjustable so make sure they are not set too low and are set to trip just before the main system controller triggers and shuts down the entire layout.


----------



## gregc (Apr 25, 2015)

Brakeman Jake said:


> Too small wires will waste current through heat thus raising the consumption of the powered component.


yes, there is wasted heat in the wires, but the total (motor and wires) power and total current is less.


----------



## flyerrich (Feb 17, 2014)

My buss wire is #14 and the drops are #18. The tripping happens with my new Atlas loco with sound as well as a new Bachmann with sound and a Bachmann switcher no sound. The three locos that I converted to DCC, two with sound one without I did a stall test on them, all where within acceptable ranges one at .7, one at .4 and one at .5. This happens running even just one factory DCC/sound loco or non sound. I ran three locos at the same time yesterday to try to figure out what was going on and the problem was intermittent in all areas of the track. I will check the setting on the breaker and see if that might be a problem.


----------



## Brakeman Jake (Mar 8, 2009)

Just a theory here since I haven't run any test and won't either but I always believed that heat is energy that has to show as current draw somewhere.Indeed,it won't increase the input current so won't show as more draw...the motor will simply run poorly.

In this case,with variable current input (throttle),the operator will crank the knob further to compensate...wouldn't this show as added current draw?


----------



## gregc (Apr 25, 2015)

Brakeman Jake said:


> Just a theory here since I haven't run any test and won't either but I always believed that heat is energy that has to show as current draw somewhere.Indeed,it won't increase the input current so won't show as more draw...the motor will simply run poorly.
> 
> In this case,with variable current input (throttle),the operator will crank the knob further to compensate...wouldn't this show as added current draw?


a voltage is generated by the throttle. It has a max voltage. It doesn't get higher if someone cranks it up.

the resistance the throttle sees determines the current. Ohms law: I = V/R

The motor could be connected directly to the throttle and it is assumed the throttle can provide sufficient current. If the motor resistance is 100 ohms and the voltage 16V, (ignoring BEMF which reduces the current) the current should be 0.16 amp = 16 V / 100 ohms.

and the power being dissipated by the motor is 2.56 Watts = 16 V * 0.16 amp. or using resistance, 2.56 W = 0.16^2 amp * 100 olhm.

most of this power results in kinetic energy, the motion of the locomotive, and some as heat, the current thru the wires of the motor.


add wires only increase the resistance. Decent wiring probably doesn't add more than 1 ohm.

let's say you use really thin wire and its resistance is 100 ohms. Now the current is cut in half: 0.08 amp = 16 V / (100 + 100) ohm. And the power is also half:k 1.28 Watt = 16 V * 0.08 amp

half that power is being dissipated in the wire 0.64 Watt = 0.08^2 amp * 100 ohm and the other half in the motor.


yes, the wires are getting hot, but the total power in this example is half what the motor would normally draw and the wires are dissipating only half of the half that the motor would normally draw.



sound like the new sound decoders are drawing more power and the circuit breaker needs to be adjusted.


----------



## Brakeman Jake (Mar 8, 2009)

I've read somewhere that the PowerCab has a built-in ammeter...wouldn't it be the very first thing to check?A high reading could come from a few different reasons but a low reading would confirm that a breaker setting is on order.


----------



## gregc (Apr 25, 2015)

Brakeman Jake said:


> I've read somewhere that the PowerCab has a built-in ammeter...wouldn't it be the very first thing to check?A high reading could come from a few different reasons but a low reading would confirm that a breaker setting is on order.


yes it does. see page 59 of the manual


----------



## flyerrich (Feb 17, 2014)

I did go to the manual and set the cab to show amps. I ran all my locos one at a time, forward and reverse at speed step 10 of 28.
I recorded the amps. showing as I ran them. My two newest locos Bachmann 4-4-0 w/sound (forward .14-.16 reverse .13-.16) At one point on the track it stopped, breaker kicked out and came back on at .01. The second time (in same place) it kicked out and came back on at .09. I had to push the loco to get it moving again. I suspect a bad rail joiner connection.
My other new Atlas RS1 with ESU Loksound (forward .14-.29, reverse .14-.33). Breaker never kicked out.
Bachmann switcher (forward .14-.23, reverse .14-.23) breaker kicked out one time came back on at .01 loco started up on its own. At no time that the breaker kicked out did I see a spike in the amp. reading prior to trip out. Rest of locos I installed decoders in and they ranged forward and reverse .14-.33 and never had breaker kick out.
Now that I have this info what are your opinions?


----------



## Brakeman Jake (Mar 8, 2009)

A faulty joiner will create a power loss,not a short.And a loss of current shouldn't trip the breaker.And the fact that the ammeter doesn't read any overload is because the breaker reacts too fast not leaving enough time for the ammeter to read.

The faulty locos being Bachmanns,I wouldn't be stunned to find you have a few wheels that aren't perfectly in gauge.Their quality control isn't the best of the trade and this problem isn't uncommon.Your description of the problems you're having points to this.


----------



## gregc (Apr 25, 2015)

I don't believe the PowerCab current meter responds very quickly. I think you're more likely to see the breaker trip before the PowerCab reports a spike and I assume the breaker trips before the PowerCab shuts down?

If the shorts are NOT due to the locomotive decoders drawing excessive current then presumably there is a short caused at the track possibly caused by the locomotive wheels as Brakeman suggested. And you mentioned that problems occurred at the same track location.

If it's track/wheel related, you should be able to measure it with a meter. You could try measuring the resistance across the rails with the power off as you push the locomotive thru that section of track, putting slight press to one side then the other. I sometimes have shorts when wheel run between the point rails at turnouts.

When a short occurs, try running the loco across the same section of track.


----------



## flyerrich (Feb 17, 2014)

the breaker always trips before the power cab shuts down. When these momentary breaker trips occur and sometimes it isn't always at a "suspected" turnout I have observed the breaker light come on and off within a second. It happens so fast, (off then back on) hard to understand how the "short" is cleared by itself. Man DC was so easy never had these problems. have to wonder if I did the right thing by converting!


----------



## CTValleyRR (Jul 26, 2014)

Do your turnouts have metal frogs and guard rails? A slightly out of gauge metal wheel may be shorting across them. Or the flangeways might be too narrow. The NMRA gauge can help you check both.


----------



## gregc (Apr 25, 2015)

flyerrich said:


> When these momentary breaker trips occur and sometimes it isn't always at a "suspected" turnout I have observed the breaker light come on and off within a second. It happens so fast, (off then back on) hard to understand how the "short" is cleared by itself.


i'm not surprised to see things cycling. Of course, once the breaker trips, the current excess is removed. So the breaker begins cycling, it waits a bit and reapplies power. If there's still an excess it repeats.

the locomotive current may fluctuate. Might be a section of track where the wheels bind a little. After the breaker trips, forcing the decoders to reset, they won't be drawing as much current when they start up. It may take a bit of time for the decoder to resume operating at the commanded speed. If there is still a current excess, guess what ..

I've heard that sound cards draw more power. I'm not sure, but perhaps a chuff or whistle draws more power as well. Previous fluctuations may not have been a problem, but now they are because the idle power is higher.

have you tried increasing the trip current on the breaker or just bypassing the breaker? The PowerCab will shutdown if the current limit is exceeded.


----------



## flyerrich (Feb 17, 2014)

I will try bypassing the breaker first and see if it changes anything. Then change the trip current to see if I can resolve this. I ran my Atlas and Bachmann last night both have sound, ran them for 15-20 minutes and all worked fine then the next 15 minutes I got the quick trip and reset of the breaker at least twice it happens that the Bachmann was in the same place on a turnout but "before" the metal frog. Thanks


----------



## Brakeman Jake (Mar 8, 2009)

If everything goes fine for a while then troubles begin suggest that the breaker resist tripping when cold but gets warmer as time goes on,lowering the tripping threshold.Raising the tripping level may be the solution.

Does the breaker get warmer?


----------



## flyerrich (Feb 17, 2014)

I turn the heat up when I start running the layout. Room is about 62 degrees when I start operations, lol.


----------



## gregc (Apr 25, 2015)

when there's a problem that hasn't occurred before, it make sense to consider what has changed recently. You mentioned new decoders.

but you also mentioned problems at a particular location on the track. Perhaps there are multiple problems. But was there a problem at this track location before?

Could there also be a track issue, as other have suggested, caused by a wheel possibly shorting between the main and open points rail? There could be a momentary short which clears after the locomotive has moved past it. The circuit breaker trips, but the locomotive continues to move and when the circuit breaker restores power, there is no short.

don't understand why a track problem wouldn't have been observed before.

I'm constantly debugging RF software problems. They all have a rational explanation.


----------



## flyerrich (Feb 17, 2014)

The particular track area was not a problem before. I didn't have "any" problems before when it was all DC. The area in question is between two turnouts (Atlas) that are back to back. The loco passes through the first turnout but always stops just before it hits the metal frog area of the second turnout. I feel there is a problem with the turnout. I will be changing it out sometime in the next couple of days and see if that helps. The biggest problem it seems is the Bachmann 4-4-0. With such a short wheel base on the "4" drivers it may be allowing it to touch the point rail and causing the short situation.


----------



## Lemonhawk (Sep 24, 2013)

I can see the 4-4-0 stopping on an unpowered frog but that would not cause a short. The atlas turnouts sometimes had the 2 rails exiting the frog really close together in the plastic frog such that a wheel could sometimes short across the 2 rails. Look closely at the frog exit and see it the rails are close together and exposed. It's possible a little nail polish would cover the the rails and eliminate the short, not sure how long that would last. See "Cp -6 circuit breaker" in this forum, it talks about a successful use of nail polish.


----------



## CTValleyRR (Jul 26, 2014)

flyerrich said:


> The particular track area was not a problem before. I didn't have "any" problems before when it was all DC. The area in question is between two turnouts (Atlas) that are back to back. The loco passes through the first turnout but always stops just before it hits the metal frog area of the second turnout. I feel there is a problem with the turnout. I will be changing it out sometime in the next couple of days and see if that helps. The biggest problem it seems is the Bachmann 4-4-0. With such a short wheel base on the "4" drivers it may be allowing it to touch the point rail and causing the short situation.


I would suspect the turnouts. Use your NMRA gauge to measure all the clearances in the turnouts and correct anything that's out of spec.

DCC is more sensitive to these kinds of issues than DC is, but, at least in my opinion, the advantages outweigh that drawback.


----------



## gregc (Apr 25, 2015)

flyerrich said:


> The loco passes through the first turnout but always stops just before it hits the metal frog area of the second turnout.


do you mean over the points or from the diverging side of the turnout.

A common problem is wheel shorting between the main rail and open point. It's hard for me to imagine how a short can occur on the diverging side of the turnout.


----------



## tr1 (Mar 9, 2013)

______________________________________________________________________________________________________________________:sold::dunno:


----------



## tr1 (Mar 9, 2013)

*Incorrect answer previously.*

It seems I have misspoke earlier on wire thickness and length and resistance._'m sorry for my incorrect answer.
Regards,tr1
Mark Gurries Webb sight on wiring for DCC:smilie_daumenpos: Check it out Man!_


----------



## flyerrich (Feb 17, 2014)

Thanks for all the help/opinions. I finally got things working satisfactorily. Circuit breaker working fine all locos running fine. I added some more drops to the buss line. I also removed an Atlas turnout (had metal frog) and replaced it with another spare I had metal frog also. One particular loco would always stop in the turnout just before the frog. I could never find anything wrong so I changed it out and that particular problem went away (?). Only thing I could point to was one of the movable rails seemed very loose at the rivet point maybe causing momentary power loss. A lot of times the loco would stop, breaker would trip momentarily come back on and loco would start moving again. I could never see any wheel flanges causing a problem. Any future track additions I will use Peco. The rest of the turnouts seem to be working ok. I don't want to tear up a lot of track to install Peco at this time because most is already ballasted.


----------



## Lemonhawk (Sep 24, 2013)

Unless you go to a lot of trouble, those metal frogs are not powered and hence engines with limited pickups may stall on the frog. The loose hinge would cause the point rail to not have power so now the point rail and the frog are all unpowered and you have more trouble!


----------



## flyerrich (Feb 17, 2014)

Thanks guys for all your help/ideas to fix my problem. Things are working fine now (at least for the moment) I changed out a couple of the Atlas turnouts, removed and rerouted some track areas.
I had conversation with Erik at Tony'sTrains where I purchased my NCE PowerCab. He advised me to clean the track and make sure it was "clean". Then if I still had problems (which I did but were less often)to change a couple CV values he gave me on the DCC Specialties PSX-1, which in effect added a small amount of time delay in the circuit breaker tripping. After that things where 100% better. 
I also wired up my "Loop" section to my PSX-AR, which I had left unwired because of the other problems I had and didn"t want to confuse the issue anymore. Wiring the loop into the reverser was simple and went without a hitch.
Can't say enough about you guys and the free help you afford us and also Tony'sTrains for super support.


----------



## Lemonhawk (Sep 24, 2013)

Maybe just to complete this, you might mention was CV were changed and what the original and changed values were. It would make it easier if some one has a similar problem to find the actual solution. Great that you now have the reverse loop working!


----------



## flyerrich (Feb 17, 2014)

Lemonhawk,
Your right I should have put the CV values down. I don't know what they where originally, they where factory set values. What was suggested to change them to was CV55=1 and CV65=128. This gives a longer delay in the circuit breaker tripping to overcome small electrical spikes.


----------

