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Frustrated By Poor Electrical Conductivity ?
 Moderated by: Si. Page:    1  2  3  4  Next Page Last Page  
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 Posted: Sat Nov 12th, 2016 09:05 pm
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Reg H
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All you DCC gurus, I need serious help.

I have NEVER had so many continuity problems in my layout wiring. Prior to the installation of the current DCC system I have always used cab control, and we are talking 50+ years of history in HO, O and On30.

I am going nuts.

The track is clean.

All rail joiners are soldered.

Every stretch of rail between rail joints has feeders connected to a large gauge bus.

My total bus length is way inside Digitrax guidelines.

The only place I stray from DCC orthodoxy is that I route frog power through the points. But I am not having trouble there.

I will start a train out, it will run for a ways and stall. I clean the train (again) and away it goes, until it stops again.

Re-cleaning the track helps, sometimes. Sometimes a loco will run through a stretch fine forward, and stall in the same place, every time, in reverse.

In one spot the loco stalls right over a pair of power feeders!!! Sometimes. Cleaning the track at that spot helps one time. Next time through that stretch it stalls again.

All this whiz-bang technology might be wonderful, but if I can't run trains it is pretty useless.

I am just about to rip out the DCC and go back to cab control. Which is more work than I would like to do.

I need some ideas.

Reg



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 Posted: Sat Nov 12th, 2016 09:22 pm
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Si.
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Hi Reg :wave:

Are you getting the correct Voltage on the track, from the controller ?
Have you got a multimeter to check this ?

If you can leave the meter connected & try running a train...
...you might be able to see something useful on the meter.

:moose:

Si.



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 Posted: Sat Nov 12th, 2016 10:13 pm
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Reg H
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Thanks, Si. I will give that a try.

Reg



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 Posted: Sat Nov 12th, 2016 10:20 pm
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2foot6
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Hi Reg,I have suffered similar problems in the past,despite popular believe,I found the rail can be to clean causing DCC problems.What I do about twice a year is place one drop of light oil on my finger tip,then run my finger along the top of the rail for about two metres(6 feet) then run a loco on the track to spread the small amount of oil.This idea may disgust or horrify many modelers,but it does work(at least with our climate).This idea is worth a try before ripping out the DCC :old dude:..........cheers Peter.



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 Posted: Sat Nov 12th, 2016 11:11 pm
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Herb Kephart
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I Have done the very same thing, way, way back in the days when I thought that rails should be powered. I used ATF (auto transmission fluid). Don't forget that the other side of the connection, wheels, must be clean also.

Now, all that nonsense is in the past. And NO, I don't push the loco around by hand, or pull it with a string-----

Herb



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 Posted: Sun Nov 13th, 2016 12:45 am
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Reg H
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Out to the garage to grab the multimeter.

No multimeter.

Must be in the hangar.

Jump in the truck and dash up to the airport.

Open the hangar, rummage in the tool box and retrieve the multimeter. A digital RadioShack unit I have never liked.

Back home and down the basement.

Check the track. 0 Voltage.

Hunh.

Maybe its the batteries in the multimeter.

Upstairs to the battery drawer. Six 9 volts, a HUGE package of AA, several C-size. No AAA.

Off to the hardware store to buy batteries.

Got to the store and decided to chuck it and buy an analog multimeter. The old fashioned kind with an actual needle.

Back home and down the basement.

Fourteen volts everywhere. I thought it was supposed to be 17 volts.

Break out the Digitrax instruction materials (last resort). Can't find where I read it should be 17 volts.

But it does say, in several places, make sure the wheels and track are clean. I have cleaned the track to within an inch of its life.

Wrestle around and figure out a way to clean the wheels on the loco.

VOILA!!!

Problem solved. It even runs great on track that hasn't been cleaned in weeks.

Call the grandkids to the basement and run the train back and forth a few times.

Everybody is happy.

:)

Reg

PS: I have NEVER cleaned the wheels on a 1/4" scale loco. But then, my previous foray into 1/4" scale was standard gauge and those locos seem to weigh about 10 lbs each.



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 Posted: Sun Nov 13th, 2016 01:17 am
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Si.
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A few words from the Web concerning oil.

- - - - - - -

Organic compounds such as octane, which has 8 carbon atoms and 18 hydrogen atoms, cannot conduct electricity.
Oils are hydrocarbons, since carbon has the property of tetracovalency and forms covalent bonds with other elements such as hydrogen, since it does not lose or gain electrons, thus does not form ions.
Covalent bonds are simply the sharing of electrons.
Hence, there is no separation of ions when electricity is passed through it.
So the liquid (oil or any organic compound) cannot conduct electricity.


Oils conduct electricity minimally under normal conditions, which makes them useful as insulators.
The extent of electrical conductivity depends on the concentration of impurities.


Lubricants are normally only slightly conductive and therefore can work as insulators in transformers or switches.


Best Answer: That's a big no.
The same chemical properties that make it so oil and water don't mix makes it so oil cannot conduct electricity ... ever ! In fact.


A classmate of mine saw a video of a mineral oil submersed computer and I'm slightly skeptical about the idea, he wants to build one.


The very same characteristics that makes it a good lubricant also makes it a good insulator.
Engine oil does not conduct electricity because there are no charge carriers in it.


Oil does not have the free electrons necessary to conduct electricity.
The mineral oil is non-conductive, so the electronics do not short out.


:brill:


Si.


Not known for great traction either.


:f:



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 Posted: Sun Nov 13th, 2016 03:14 am
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oztrainz
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Hi Reg,
give graphite a go first- look for a Progresso Woodless pencil or similar at your local art store - you are after 2B of 4B grade GRAPHITE pencil. Caution - There is a charcoal pencil that looks similar. You need the Graphite pencil.

This will keep both your track and wheels clean - The real advantage for graphite appears to be at thin layer thicknesses after its application to clean track. (Look up "graphene") Graphite appears to actively inhibit micro-arcing and the formation of "black gunk" (oxides) on both the railhead running surfaces and the wheel treads. As evidence, I post this photo of a wheel set that hasn't been cleaned or needed to be cleaned after 5 years running on graphite treated rails.



Yes you can see a wear pattern but there is no evidence of oxides and no build-up on the wheel treads. With clean surfaces like this wheel tread, conductivity is maintained between each wheel and the rail it is running on. This reduces both the incidence of wheel cleaning and track cleaning by at least a factor of 2 and in some reported instances to over a year between track/loco wheels/wagon wheels cleanings.

To get the best advantage out of graphite, you need to -
1 - Clean your track well (you've already done that
2 - Clean your locomotive wheels (the aim is to get volts from the rails, through the wheels to your decoder and motor)
3 - Clean ALL you wagon wheels well ONCE (Q-tip and white spirit has worked well for me in scales from N to O)
4 - Apply graphite to each the top and inner running faces of the rails in front of your locomotives. (so that when you run trains the clean wheels will run through the graphite)
5 - Run trains all over your layout (this distributes a THIN (as in almost molecular thickness) layer of graphite around all the tracks
6 - anywhere there is a hesitation, apply a light swipe of graphite for about 2" to 4" before and after where the hesitation occurred and run more trans over this stretch of track. After 2 or 3 passes this stretch of balky track should no longer be "balky".

To show how difficult it is to apply graphite, check out the following video https://youtu.be/VPaVM7h2fno Remember to do each rail.

Now some limitations -
A - If you are running your locomotives at their limit of adhesion you may have to back the load off slightly. (Method - cut your load in 1/2 and then gradually increase your load until the locomotive starts to slip. Then back your load off slightly until your locomotive no longer slips. One of the Canadian clubs that runs multiple locomotives, multiple mid train helpers and 100 car plus trains up 2.5% helixes has reported a little or no reduction in tractive effort from their locomotives and have reduced track cleaning every month to once in 9 months.
2 - A grade is a grade - The impact of the grade on the amount of wagons a locomotive can tow far outweighs the influence of any rail surface treatment.
3 - Graphite at the rails cannot fix any mechanical binds in the drive train. If you have a dodgy mechanism, you have a dodgy mechanism that must be repaired before you can get the full benefit of graphite and better conductivity at the wheel/rail interface.

Now having seen earlier that you are now running, give the wheels of your wagons good clean and give graphite a go - you might be pleasantly surprised how much more time you can spend running trains rather than cleaning track ;)

Last edited on Sun Nov 13th, 2016 07:09 am by oztrainz



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 Posted: Sun Nov 13th, 2016 05:57 am
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pipopak
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Also remember to clean where the pickup wipers rub the wheels and the wipers themselves.
Jose.



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 Posted: Sun Nov 13th, 2016 05:59 am
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Si.
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Graphite ... :thumb:

Oil ... :doh:



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' Mysterious Moose Mountain ' - 1:35n2 - pt.II
http://www.freerails.com/view_topic.php?id=7318&forum_id=17&page=1

' M:R:W Motor Speedway !!! ' - 1:32 Slotcar Racing Layout
http://www.slotforum.com/forums/index.php?showtopic=59295&st=0&a
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