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#21 ·
Posted By Greg Elmassian on 14 May 2011 08:51 PM
No, it's possible, but not a certainty.

Just stating my experience, and I did qualify it.

Greg




Here's a thought. In the wet areas that I have most troubles, the rail does not sit on the ballast. In these areas the rail tends to sink into the soil and the ballast/dirt/sand/growth/muck almost obscures the railhead until just the tops are showing (which I really like the look). There is far more contact between the brass and the underlying materials than if the rail sits "up" with the ballast channeled around it.
 
#22 ·
Yep, sounds reasonable. My rails sit in ballast. Not sure of Pete's situation. Did not say your theory is wrong, just said it's not the only possible explanation.

I know you like the look, but probably not the best for running, since you state you have the most problems where the track is basically immersed in non-ballast.

Anyway, on layouts with ballast and drainage, I have found that while there is some resistance added between the rails when wet, it would not explain the trains slowing down.

On your layout, it probably could, depending on the conductivity of the soil, length of exposed track, etc.

Pete did not state the condition of the ballast/other material around his track as I remember...

Sorry to have upset you.

Greg
 
Discussion starter · #23 ·
This is some good information thus far. Life has been preventing me from working on my trains at all in the past few weeks. My job has been killing me, I'm going into the hospital on 5/20 for surgery and I recently purchased my first home. It's a three 3 family that needs a lot more fixing up than I originally planned. With those things plus the abundance of rain we have had lately its been hard to get out to the layout.

That said I will be home recovering most of next week... I should have time to get out and try some of the ideas you guys have mentioned.

As for measuring track voltage I have a pretty good digital multimeter from radio shack. I think my measurement of 22V to the rails is accurate. When I set the voltage I measured across two locations inside the booster as shown in the NCE manual. When I measure on the rails I get more or less the same voltage +/- ~0.2V

Also as far as voltage leaking to the ground that is possible. My tracks sit on 1/4 inch blue stone gravel about 3-6 inches deep. In most spots the rails sit above the surrounding ground. That is to say the road bed was built up as apposed to laid in a ditch. I used to have bad drainage issues before last summer but then I changed and re-laid all my rails. Now the drainage is great! That said I have often noticed that when it starts getting cool and dark my trains don't run as well due to power issues. I always attributed this to dirty track or the rails contracting as they cool and messing with the joints but perhaps there is more.

As soon as I get a chance to test I will report back and let you know what I find.

-Pete
 
#24 ·
While your voltmeter probably does not read accurately, since it needs to be a true RMS AC meter, it is sufficient to measure at the booster output and then at various places along the layout under load. Remember that reading the voltage not under load tells you basically nothing.

Anyway, take it easy, get through your personal stuff, and let us know how it progresses once you are back up to snuff.

Regards, Greg
 
#25 ·
It is not my desire to contradict anyone. I am no engineer (other than in the "Woo Wooo" sense), but I must report on my own experience relative to my S4 mentioned earlier in this thread.

I have installed an NCE D808 decoder to replace the NCE 408 which seemed to be causing an anomalous speed problem. With our rather constant rain lately, I have been able to run the S4 only once, but it now runs just as well as it originally did with the 408 installed. I was able to open the throttle all the way to 28 with smooth increase in speed. I even ran it with my new GP-40 - running around the entire layout at a distance of less than five feet. Neither unit showed the slowdown mentioned in my previous posting.

This does not necessarily contradict anyone. I am no engineer (other than in the "Woo Wooo" sense), but it does seem that the 408 had developed a problem that was causing the slowdown of the entire railroad when the S4 was raised above "notch" 17. This is not necessarily proof that the 408 cannot or should not be installed in a USAT diesel, although NCE does warn against it. It is certainly possible that something like a dead short could have harmed the lil' ol' decoder. Or a factory defect could've made it an accident waiting to happen.

Anyone want this "defective" 408 decoder to test with proper lab equipment? Might be a lesson to be learned.

JackM
 
#26 ·
Sure, send it to me.. very interesting.. trying to think what the problem could be, maybe a short in an output transistor that puts a huge load on the power?

(but isn't it under warranty? I'd first see if NCE will fix for free, and if they are interested to investigate... this will probably require a call to Larry at NCE)

I've run 408's in a lot of locos with nary a problem, and conversely, I have melted a D808 down to silicon slag once... but ALL things are possible.

Regards, Greg
 
#27 ·
Greg -

The unit is well out of one-year warranty, and even further since there's the clause about beyond the loads it was designed for. I'd be happy to send it to you; might be interesting. Or it could just be my old nemesis "operator error". You could send me your snail address at: ccrr@frontier.com .

JackM
 
Discussion starter · #28 ·
So a quick update. I haven't had a chance to do much. My surgery was more intense then expected and the recovery was a bit tougher then I thought it would be. I did get to test the SD45 that was smoking when it derailed. I had to reprogram the decoder again but it runs like before.

I purchased some 14 gauge muilt stran wire and some plugs so I can wire up something more sturdy that can definately handle the amps required coming out of the DCC booster. I am going to wire it up and then do the testing. See if I get the same result with better wiring.

-Pete
 
#29 ·
SD-45's have 4 motors each, as do the Dash-9's. That is a total of 24 motors, plus engine lights and smoke, there is a lot of power consummed. Also are there cars drawing power (sound units, lights?)

Thinking about problems mentioned, wet rails will cause a loss of traction, so try making the consist shorter.

All trains slowing on the track could be power loss in the track feeders. I suggest at least 14 guage wire be used and have several leads run from the power source to different points around the layout. 12 guage is even better.

Also, what size and length of wire is used from the power pack to the command/central station. There could be a loss there also.

Peter did mention he is using a regulated supply, but I do not remember seeing the wire length used for pack to station, nor station length to track.

The 2 dash9's (8 motors) with the coal drag could be using 4 amps, that leaves 6 amps for the 4 SD-45's with 16 motors, and I would suspect a big starting current from these 16 motors.

It would be interesting to see what the zimo system hand held current readings would be on Peters RR. How far are you from Train-Li in Upton??
 
#30 ·
Dan, when I re-read Pete's first post, the first train has a lighted caboose and 2 logos, and indeed, the second train was 4 locos with an unspecified consist.

BUT re-read the part where one train stops and shorts out, and has a burnt smell.

I believe the key here is the other train kept running. I think that's a big clue to not supplying enough current, since it would seem very likely a second train PLUS a short (enough to start burning something) should have tripped a breaker.

Combine that with the other parts of the story of trains slowing strangely and it really sounds like a power delivery problem.

Regards, Greg
 
Discussion starter · #31 ·
Dan,
I am about 25-35 minutes from Axel and Joane. I purchased a bunch of track and other supplies from them last summer and this. Actually the new guy there Mike in my buddy from hghschool.

So the Zimo system tells you how many amps are being used?
 
#32 ·
Sounds like we have a little confussion here. We need to go right to the chase. Get you a ramp meter which will read the volts (DCC AC) and check what is coming out of your system. If the volts read 21 volts at the out put of the booster then you now can start tracing where the power loss from there. Later RJD
 
#33 ·
How do systems really work? If I draw the max current available from a command station/power supply, what will happen?

Shutdown of one or the other?
Output starts pulsing due to approaching overload? Which unit, power pack or command station?

If current is not near the max then this would not matter, but Peter did let us know he is running 6 diesels with 4 motors each for 24 motors and a caboose with lights. Do the engines all have lights on and what about the smoke units.

Lots of questions, but one thing is certain. When the 4 diesels start up, the 2 diesels slow down. Must be a power loss, but maybe not in the wiring, so every piece must be checked in the power distribution. To assume one thing is bad is not the way to troubleshoot. One must verify each and every part of the power distribution.
 
#34 ·
I own the same system Dan. I and many others know how an NCE system works. We know what happens when you pull max current.

He's not pulling 10 amps if there are no defects with the locos. I've run more locos with more load on an NCE system, and I'm sure his grades don't exceed my 60' of 3.5% grade. I know what locos take full slip, believe me.

FYI, the NCE works just like the zimo, and everyone else's, they run to max rated wattage/current and then shut off at overcurrent... there is no tapering off of the boosters if the power supply is a regulated supply and can put out 10 amps minimum. (By the way, if you give it enough current, the NCE will actually supply up to 20 amps for a short time, but it cannot continuously dissipate that much heat)

You do say it must be a power loss, but maybe not in the wiring. I'm confused by what you are saying? Other than the booster, the wiring and the rails, there is nothing else.

I think I've been espousing that you look for power drop at the rails under load, and trace back, and it's either bad rail connectors, or insufficient wire gauge in the feeders. (or both of course)

Anyway, a simple application of a voltmeter to the booster output and then at points further away, under load, will identify the problem very quickly.

Measuring the amps alone really will tell you nothing unless you are actually out of current. I can tell you that is not so (out of current), since even with a short on one consist, there was power to allow the other consist to operate. (the Zimo also cannot put out as much current as the NCE so if you were already out of current with a 10 amp NCE, you would absolutely be overcurrent with an 8 amp Zimo).

Here's the crux, If you were out of current already, then added a short (as indicated) , there would be nothing "left" to run a train on. But he indicated the other train kept running.

That piece of information alone makes it pretty sure it is a power delivery problem between the booster and the loco. The resistance in the system was enough that the short did not take "all" the current in the system. Surely the short circuit drew MORE current than when both consists were moving.

Thus I cannot see how the system is out of current (from the booster), so I cannot see why measuring the current tells you anything really important as compared to the voltage drop, which MUST be occurring.


Let me know if there's a flaw in the logic here, but the pieces of information provided tell you a lot actually.

(This is actually fun, so we can see what was the real problem later... seeing how to fit the data to the "theory") I could be dead wrong....


Regards, Greg
 
#35 ·
Posted By Greg Elmassian on 14 Jun 2011 09:08 AM
Let me know if there's a flaw in the logic here......
Sorry Greg, but I have to agree with what you posted.


Everything you said in your last post is 100% correct.
If the train slows down by itself, it's a drop in voltage, not current.

If there is no true-RMS meter available to measure the DCC voltage, one can always use a diode bridge ahead of the meter and use the DC scale of the meter rather than buying a Rampmeter just forthese tests.


Knut

Oh....The reason I'm sorry that I have to agree is because I love to take an opposing position so that I can have an animated discussion - unfortunately not possible in this case.
 
#36 ·
Even an ordinary AC voltmeter can be used, just for relative measurements, you use whatever reading you get right at the booster, and then see how much it drops (under load) at the "trouble spots"... so if you see 3 or 4 volts drop, even though it's not a DCC rms meter, you know where the problem is.

And the diode bridge makes it exact, since DCC is a square wave.

Sorry Knut, we'll agree to disagree some other time hahahahaha!

Just trying to help poor Pete, he has enough on his mind, so trying not to argue with Dan, but to give Pete the most straightforward, quickest and easiest way to debug the problem. I've seen people go around and around in circles measuring stuff that really does not lead to the root problem, but just to more confusion. There's no reason to connect a completely different DCC system just to measure current, my opinion.

Regards, Greg
 
#37 ·
Posted By Greg Elmassian on 14 Jun 2011 03:19 PM
Even an ordinary AC voltmeter can be used, just for relative measurements
Depends on the specific meter used.

The inexpensive ones only have one or two ranges for AC, I just checked two of the $20.- ones I have kicking around and one has a single 600 VAC range, the other a single 750 VAC range (DC volts, DC amps and Ohms have lots of ranges)

So trying to read a 3 or 4 volt difference on those AC ranges might be a problem.

They are also calibrated to measure a 50/60 Hz sinewave; I have no clue if these meters would even indicate anything useful at the DCC frequency - but I have no experience in that respect.

Those same inexpensive meters have a number of DC scales, all the way down to 200 millivolts, so measuring a few volts difference with the 20 or 50 VDC range would not be a problem and the DCC frequency is no longer an issue.


I'm not arguing with you Greg - my point is really that one has to know and understand what the particular meter one uses is capable of measuring and to use the proper procedure.


Trouble shooting a problem like that via web posts is tricky at best, not having reliable information just makes it so much harder if not impossible.


Knut
 
#38 ·
I know you are not arguing... this is interesting stuff to talk about, and it's really probably the only place on the web these discussions take place where many people can read and participate.

Yeah, forgot that many AC scales are WAY high..

Most cheap meters do fine on DCC on the AC scale, in terms of relative measurements.

This is more fun than talking about the weather, and more stimulating!

Greg
 
Discussion starter · #39 ·
Update!
So I corrected some wiring issues on the layout itself, and replaced a few failed rail clamps where I noticed they had gone bad. So now the layout seems to be running like clockwork.

Then I decided it was time create a more permanent set up for my control systems.

I have two systems. DCC and the trackside TE. I cannon have both hooked up to the tracks at once as they will short each other out. So I have a 12 guage multi strand wire running all around the layout with leads running to the tracks everu 20 -30 ft or so. The end of this runs into my shed and thus far I have been connecting it to either control system via alagator clamps. Fearing that my shotty wiring might be contributing to the issies I am having I made a point to make a more permanent set up.

Home depot sells standard 120V 15-20 amp heavy duty plugs for extension cords and what not. They pop open with two scres and then they have 3 screw terminals inside for hot, neutral and ground. I purchased 1 male and 2 female plugs. For my track side TE I used a 3 ft strip of 12 guage wire. Attached one end to the screw terminals on the TE and the other I equiped with one of the femail plugs.

An important note is I am using the female plugs on on the the wires coming out of each control system. That way I can't mistakenly plug them into the wall and fry them.

For my DCC system I purchased some multi strand 14 gauge wire as the 12 guage was a bit too large for the screw terminals on the unit. The booster has two positive and two negative terminals for power in and two of each for power to the rails. I took advantage of this and ran two 14 guage leads (4 wires) from the power supply to the boster and two from the booster to the rails. Again the leads going to the rails were equiped with a female 3 prong plug which mates up with the lead going to the tracks.

When I looked at the wires I had been using I was a bit ashamed of myself. I had used 18 guage speaker wire, with a single set of leads for the DCC system, plus a set of alagator clamps to connect to the rails. Not sure what I was thinking.



So after all the wiring was done I did some testing. Same configureation as last time. Two consists totallying 6 disels in all. 4 SD45s and 2 dash 9s. This time I didn't have a train behind either consist however, just the engines. First off things just seem to run a bit better with more robust wiring. Each loco should pull about 1.5 amps. With 6 locos that is 9 amps all together so I should still be undet the limit. But when one consist speeds up the other still slows down. Although now the effect is much much less. Previously both consists at full throttle would max out at abotu 50% of their normal speed. Now at max throttle for both consists they are running at 75-80% of their max speed.

With both running at full throttle I hooked my multimeter to to the output terminals of the PSU and got 30.1-30.3 VDC. At the rails im getting about 21.5-22.0 VDCC. I was not able to measure the amps correctly as when I put the multimeter in line I with the sytem the trains would not move. I am going to have give this another shot durring the week.

One thing in particular that I noticed as I was closing up shopt for the night was both the PSU and the booster were very warm/hot. They were working pretty hard.

-Pete
 
Discussion starter · #40 ·
I should add that the NCE manual gives instructions on how to measure/adust the track voltage by taking a reading from two points inside the the booster using a multimeter set to DC. When I measure at these points, and measure the AC voltage coming out of the unit I get almost the same reading, +/- 0.5 volts. My multi meter is digital and self adjusts to the voltage type and range. I am pretty sure its getting the track voltage right. If not its pretty close.

Also incase I did not mention I to have multiple leads supplying power to the rails. I have a continuous line of 12 guage lighting wire runruing under the tracks with feeds coming up every 20-30 feet or so. Under normal opperating conditions my trains run at a constant speed at all points on the layout. I only get slow downs when I run this many large locos.

Ultimately my goal is to be able to run up to 7, maybe 8 of these at once. I like the big 6 axle power and I like mainline railroading. Big consists, big locos, long trains. :) My friend and I joke around that we collect big locos to help pull all our other big locos around. :D :D
 
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