# Strange phenomenon



## Peter Brayshaw (Jan 28, 2009)

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Hello Everyone. This is something I posted over on the Aristo Forum where I spend most of my time. But a few peopel suggested I post my questions here too. I also spoke with Axel from Train-Li about it. 

Last night I was running some more trains and looking for any issues. I had two dash 9s pulling a coal drag about 30 cars long with a lighted caboose at the end. While that was making its laps around the back yard I added 4 more sd45s to the rails as a second consist. The weird part was every time the sd45s started to move or speed up, the coal train slowed down. Now this reminds me of my old HO days if too many trains were on the rails they would run slower. But in this case they were all DCC locos and I have a 13 amp power supply powering the layout. The booster is only capable of putting out 10 amps so I would assume if I had used that many amps I would have blown a fuse or melted the booster or something. I doubt if I actually hit 10 amps. You guys have any thoughts on this?

To make things stranger the sd45 consist jumped a switch and shorted out. But the coal train kept going. When I went over to the sd45s the lead one had lots and lots of smoke coming out of it and i could smell burnt plastic. I don't know if shorted out because it jumped the switch or if it was just coincidence or what. I think it was just the loco that shorted out because the rest of layout kept operating. Anyhow The smoking unit seemed to move again as i tried to pull it off the switch, but then i stopped it. I haven't I decided to let it cool down for the rest of the night and haven't tested it yet.

Not sure if this is a DCC issue, a lack of power issue, or something else? It is very strange to me.

-Pete


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## Peter Brayshaw (Jan 28, 2009)

My PSU is 351W 27 VDC 13 A regulated (i think) with a voltage adjustment range of 26~32 VDC. The voltage tolerance is +/- 1%, line regulation +/- 0.5%, load regulation +/-0.5%. I am not sure what the last two refer to exactly but the voltage tolerance should mean it only differs by 1% or less than a volt in this case. It also lists "100% full load burn-in test" as one of its features. Not completely sure what they mean by that.

Now when I first got my DCC system I powered it with my Aristo Elite which worked but the locos only ran at about 75% throttle. This was due to a voltage drop of about 5V through the command station/booster and decoder. The Elite puts out 22 VDC at 13A and is a very very nice supply. But with a 5V drop that means only 17 volts at best. I got the above supply so I can get 22 V to the rails which makes a big difference in performance.

Anyhow, the reason I thought it was strange was because not only did the locos slow down, but with both conissits at full throttle, they were both running at less than 50% of their top speed. I have run big lashups before with my trackside TE and I don't think I have ever seen the load on my Elite go past 6 amps or so. That is why I was somewhat supprised.

A few suggestions have been made on things I can test. The voltage across the terminals of the PSU under full load, and coming out of the booster as well as on the tracks as the trains are running. Also the amps by putting my multimeter inline between the psu and the command station.

For once power distribution around the layout didn't seem to be the cause of the issues. But as far as wiring goes my tracks are fed by 12 gauge multi thread outdoor wiring. but the wires going from the PSU to the DCC system, and the DCC system to the track feed(s) is only a about a 16 gauge wire. Could this be causing the issues?

Also the terminals on the DCC system seem to be set up to only accept a 16-14 gauge wire. Could this cause this sort of issue?


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## chuck n (Jan 2, 2008)

The first thing I would check is the amps that each engine draws. If you are close to the maximum amperage, you may have problems. How often have you been somewhere when the Air conditioning unit kicks in as the lights dim. With what you were running I think that you were close to maxing out. 

Chuck


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## Greg Elmassian (Jan 3, 2008)

Very possible you have voltage drop issues on the layout, and you can have a short and still have voltage elsewhere, in fact that reinforces the theory that you have voltage drop (conductivity) issues. 

The way I track these down is put a big load on the rails (I have a box that clips to the rails and draws 8 amps) and measure the voltage drop right there. 

You can use thicker wire right after coming out of the dcc booster, remember the resistance (loss) from wire is a function of the wire diameter AND the length... so short sections of 14-16 gauge won't hurt. 

Greg


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## Dan Pierce (Jan 2, 2008)

A well regulated supply does not lower its output with a line voltage reduction, this is why they are called regulated supplies!!! 

All the regulated supplies I have seen will tolerate a 10 percent change in line voltage and the output will be constant. 

Also, my elite has an adjustment inside and I set it to 24 volts instead of the Aristo 22.5 setting. 

All the LGB supplies I have seen are unregulated as is the Aristo Ultima.


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## Cougar Rock Rail (Jan 2, 2008)

What kind of central station are you using? What kind of rail joiners? My suspicion is that when the load increases you are losing voltage through some bad connections or to ground etc.  As Greg suggests, put a load on the rails and go around to each joint and find out if there is one or more bad connections. Also, I'm wondering why your central station didn't trip immediately with the locomotive shorted. Maybe you can adjust the setting to make it shut down more quickly. 

Keith


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## Bob in Kalamazoo (Apr 2, 2009)

I guess the first thing I would check is the current output from your DCC when you have all of your locos running. See how much current is being demanded from the DCC first. Also you might want to check to current into the DCC system and the voltage level when things slow down. Certainly, as has been said, if you have poor connections on your track you could have a short and it would not shut down the DCC system. Then I would want to know if it matters where on the railroad the slow locos are? 
Bob


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## Peter Brayshaw (Jan 28, 2009)

Thank you for the info thus far.... 
To add some more info.... My command station and booster are NCE. I use the 10 amp radio equipped system. As far as the trains on the night in question they were running uniformly around the entire layout. That is to say all the connections were good and the trains did not slow or stall due to track issues. I was able to run one train at a time with no issue. They only slowed when I tried to run both consists at once. The effect was also uniform around the layout as well. 

-Pete P.S. 

Is there a way to increase font size on this forum?


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## Cougar Rock Rail (Jan 2, 2008)

Hi Pete, 

I think it must be the NCE station that is the limiting factor on output. 2 Dash 9's plus 4 SD45's is 8+8= 16 motors isn't it? So under heavy load each of those motors must be an Amp each which puts you way over the 10A. I don't know much about the NCE gear, but I think I'd be looking at why it didn't trip out when the SD45 shorted. Can't you adjust the time to shut down when a short is detected? 

Keith


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## Greg Elmassian (Jan 3, 2008)

When you put additional motors in a loco, it does not draw much more than one single motor under load. The same goes for multiple locos. There is of course some loss of extra lights and frictional losses, but basically if you need 3 amps to pull a train with one SD45, then two SD45's pulling the same train will be about 3 amps too. 

The NCE system itself (remember it does not ship with a power supply), given enough power, can put out 20 amps for brief periods. 

This is not about the NCE output, it's basically on or off... It's most likely power loss somewhere, or a defective power supply (which I doubt). 

Trains running well does not mean you don't have issues... double the load will show up problems you did not realize you have. 

I think we've given a number of suggestions, let's hear the results of testing. 

The first should be current and volts at the output of the power supply (where it is going into the NCE booster)... 

Next I would suggest my load test at the far end (electrically) of the layout. If you can deliver your full 10 amps out there, that's half the battle. 

Greg


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## Cougar Rock Rail (Jan 2, 2008)

Pete, 

One thing you mentioned was that it was at night....was it damp or cooling/condensing that night? That will make any grounding/voltage leaking problem much worse I believe. I would try it in the middle of a warm dry day and see if it's any different. 

Keith


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## toddalin (Jan 4, 2008)

Posted By Cougar Rock Rail on 13 May 2011 11:12 AM 
Pete, 

One thing you mentioned was that it was at night....was it damp or cooling/condensing that night? That will make any grounding/voltage leaking problem much worse I believe. I would try it in the middle of a warm dry day and see if it's any different. 

Keith 

I've witnessed this same phenonom for my track power and even noted it on the Aristo site, (but it was ignored).

At night the dew point drops and the resistance between the rails goes way down as current bleeds off through the moist soil and ballast. Couple this with the moisure that collects on the rails that serves as an insulator to the wheels and we have the receipe for very poor performance. This moisture on the rails also seems to promote arcing and carbon build-up on the wheels.

I clean my rail at the beginning of a session during the day (around noon) and trains run great until the sun goes down. After that, if I'm running trains, I'm out there continually cleaning the track (and wheels) to keep the trains running smoothly.

As I said on the Aristo forum, put an ohmmeter across the rails and take readings throughout the evening/night to see if this is occuring for you.


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## Greg Elmassian (Jan 3, 2008)

Be sure the DCC track power is OFF if you try using an ohmmeter!









Greg


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## Dan Pierce (Jan 2, 2008)

Moisture on the rails is very interesting as I run a pair of SD-45's with lights, smoke and sierra sound in both with everything on and in the rain. 

They run just as well as on a dry day. 

So I guess you must run on wet rails in New England to not have issues.  ;-)


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## Greg Elmassian (Jan 3, 2008)

I know there are leakage issues when the rails are wet AND it's not perfectly pure water, but I have run in the rain and with completely wet rails and never had a problem, there was plenty of voltage to go around. 

When I ballast / surface (prototype talk for re-leveling) track, I often do it with a train circulating (so I can see the improvement) and will hose the track down after dumping the ballast to wash the dust from the rails... never a problem... 

Greg


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## toddalin (Jan 4, 2008)

Then maybe you have a better explanation as to why the worst offending spot is behind the waterfall where the soil is the wettest and the second worst is next to the hot tubs that wet the tracks? These spots are even problematic during the day. 

Ask people who have trains that run behind/next to waterfalls, where the track takes the splash, where they have the most problems with trains stalling. I'm betting its similar. And yes we have hard water.


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## Greg Elmassian (Jan 3, 2008)

No, it's possible, but not a certainty. 

Just stating my experience, and I did qualify it. 

Greg


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## krs (Feb 29, 2008)

Posted By Peter Brayshaw on 12 May 2011 11:17 PM 
Is there a way to increase font size on this forum?


Just use the feature of whatever OS you're using.
On the Mac which I'm using right now, I just hold down the command key and hit the + sign to increase the font in steps (or the - sign to make it smaller.

On your train related issue - you need to take the measurements already suggested and post them here.
Right now everyone is groping in the dark and is just coming up with guesses. 

It's pretty obvious that there is a drop in DCC voltage that makes the trains run slower but it's not clear what is causing that.
If you don't know how to measure DCC voltage or DCC current then ask - you can't just use a regular multimeter for that.
The multimeter as is is good to measure the DC voltage of your power supply but I doubt that's the issue.

Knut


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## JackM (Jul 29, 2008)

Let me toss in another possibility, based on a similar problem I've had since last Fall.


My command station and booster are NCE. I use the 10 amp radio equipped system.


The light went off because I have the same system.


I noticed one day that whenever I turned up the power above 18 (out of 24), both my Aristo RDC and USAT S4 would slow down. Bringing either one up to the full 24 would stop everything. Yet they both ran very nicely as long as I kept the power at 17 or below. I started searching for connectivity issues in the track.
With the rains this Spring I haven't had much train time but saw that the problem hadn't cured itself over winter. Still figuring it was a track problem I built this gizmo:










It my patented *"V-O-M on a Stick"!* At the bottom are two metal cup-shaped things I found in one of my many junk boxes:









Now I can read track voltage without crawling around on the ground.

After a couple tours of the entire layout with nothing running, I found that the NCE was giving me a consistent 16 volts everywhere. Then I checked voltage in front of and behind the moving engines - not so easy to do with a standard pair of probes. I determined that the RDC is okay, but when I put the S4 over 17, the voltage drops. The S4 started its life working fine, but apparently now has an internal (decoder) problem.

Maybe I'm not the only one with that problem???

JackM

I am hesitant to mention this because it's common wisdom that the NCE's smaller decoder (D408) is okay in USAT engines in spite of NCE's warnings. That's what I've had in the S4 since day one. I'm in the process of installing the more robust D808 now. It's possible, of course, that the decoder died not from normal use but from an "extreme event". Or perhaps my particular unit was destined to fail under any circumstances - it only had a few months of use. I'm not drawing any conclusions from my personal experience.


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## Greg Elmassian (Jan 3, 2008)

While we wait on Pete's results, I'd say that you might want to check some other stuff in your S4, did you remove/disconnect the other electronics that were in there, like the voltage regulators. 

I've seen decoders (Tsunami) that will shut down on "over voltage", but nothing that does what you say... it's like a short over a certain track voltage... 

Greg


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## toddalin (Jan 4, 2008)

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.


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## Greg Elmassian (Jan 3, 2008)

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


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## Peter Brayshaw (Jan 28, 2009)

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


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## Greg Elmassian (Jan 3, 2008)

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


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## JackM (Jul 29, 2008)

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


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## Greg Elmassian (Jan 3, 2008)

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


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## JackM (Jul 29, 2008)

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: [email protected] . 

JackM


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## Peter Brayshaw (Jan 28, 2009)

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


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## Dan Pierce (Jan 2, 2008)

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??


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## Greg Elmassian (Jan 3, 2008)

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


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## Peter Brayshaw (Jan 28, 2009)

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?


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## aceinspp (Jan 2, 2008)

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


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## Dan Pierce (Jan 2, 2008)

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.


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## Greg Elmassian (Jan 3, 2008)

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


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## krs (Feb 29, 2008)

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.


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## Greg Elmassian (Jan 3, 2008)

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


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## krs (Feb 29, 2008)

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


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## Greg Elmassian (Jan 3, 2008)

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


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## Peter Brayshaw (Jan 28, 2009)

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


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## Peter Brayshaw (Jan 28, 2009)

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.


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## Peter Brayshaw (Jan 28, 2009)

Another update. Looks like I figured it out. 

I did some more testing tonight. First thing I did was hook up my Aristo elite power supply to the DCC system to see what it would show for amperage under full throttle. The trains ran much much slower with the elite hooked up to the system. Anyhow under full throttle the meter on the elite read about 5-6 amps. Maybe 7 here and there. 

Then I wired up a multimeter in line between the DCC system and the elite. Just turning it on it was reading about 1.5 amps in line. 

Now I wasn't using my regular multimeter as my good one was out of batteries. The one I had I borrowed from my father and I think it was only about 90% accurate. When I checked the voltage coming out of my elite it read 26 +VDC. The elite only is rated for 22. My other power supply it said was putting out 35-36 VDC or more. This is again above and beyond what the unit is capable of. 

That said I am not sure if 1.5 amps with the system just turned on and no trains running was accurate or not. 1.5 seems like a bit much. Anyhow at full throttle under the elite I was getting a reading of about 13 amps. 

Back to my other PSU and under full throttle with 6 locos I was getting 10-11 amps. This PSU is rated for 13 amps max. 

So it looks like I need more amps if I intend on running multiple lash ups with many engines and long trains. 

Anyone have any thoughts on how to remedy this issue? I hear zimo makes a 20 amp booster but I don't really want to change systems at the moment. The other systems that have caught my eye are the G wire system and Aristo's Revo. I like the idea of just hooking a generic PSU directly to the tracks. I also like the idea of having full DCC control on virtually any layout. 

-Pete


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## Greg Elmassian (Jan 3, 2008)

Peter, you only need 3 volts more input than the output you get... any more differential will be expended in heat, and can eventually limit your output. 

For 10 amps, your power delivery system is a bit light, you need independent runs from the booster to the track, not a big loop... 

For reference, I run up to 10 amps AND I use 10 gauge wire feeders, each direct from the track to the booster. 

By the way, after all the effort please get a RampMeter to measure volts and amps. 

Greg


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## Peter Brayshaw (Jan 28, 2009)

Greg, 
My power supply is a 27 vdc 13 amp meanwell regulated supply. Do you think just adding a bigger PSU would fix the problem? It seems like I would need another booster as well. Also the wiring going to the tracks should be ok if I am correct. 14 Gauge wire is rated for up to 15 amps. And 12 Guage which is what I use is rated for up to 20 amps. I am not sure if I understand why multiple leads would be better then one lead with multiple connections. 

-Pete


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## krs (Feb 29, 2008)

Posted By Peter Brayshaw on 01 Jul 2011 01:17 AM 
Greg, 
My power supply is a 27 vdc 13 amp meanwell regulated supply. Do you think just adding a bigger PSU would fix the problem? It seems like I would need another booster as well. Also the wiring going to the tracks should be ok if I am correct. 14 Gauge wire is rated for up to 15 amps. And 12 Guage which is what I use is rated for up to 20 amps. I am not sure if I understand why multiple leads would be better then one lead with multiple connections. 

-Pete 
I'll throw my thoughts in.

The Meanwell supplies will provide the full 13 amps (actually a bit more) at the voltage you set it ro, so for a 10 amp DCC system which is what I think you have, that supply is fine.

But as Greg said, the voltage you have set on the Meanwell is too high, the NCE system probably limits its current output to prevent it from overheating.
Check the DCC voltage at the output of the NCE system with a very nominal load of an amp or two.
Then set the Meanwell voltage "x" volts higher, whatever NCE recommends, I think Greg said 3 volts higher.
So if your NCE DCC voltage is 22.0 VDCC you want the Mranwell output to be 25 VDC, not higher.
Actually, 22 VDCC sounds pretty high for the NCE system unless you had a special mod done to raise the DCC voltage.

It's pretty important to be able to measure DC and DCC accurately. If you don't get accurate measurements, you are just poking around in the dark wasting your time trying to find the root cause of the problem.
What make and model is your "good" multimeter? Maybe it reads true RMS up to the DCC frequencies, then it would give you pretty good DCC readings; a Rampmeter is a good investment if you have a larger DCC layout, especially one requiring a lot of power.

Anyway - I don't think there is much point continuing until you are sure you get reasonably accurate measurements .

As to the ratings of 14 and 12 gauge wire for 15 and 20 amps respectively.
Those are parameters established for North American residential and commercial wiring using 120 VAC; they don't apply directly in our case.
Simple example - say the length of the cable run gives a 12 volt drop at 15 amps - that's a 10% drop with a 120 volt line - you still get 108 VAC at the load end which is probably adequate to drive whatever is there.
But in our case, with a 22 VDCC source voltage you would only get 10 VDCC at the load end, ie loco decoder, which would be too low.

Now, I assume your runs are not long enough to cause those voltage drops, I'm just illustrating my point. 


For our purposes, just look up the resistance of the length of cable you are using, remember there is a leg going out and a return leg, so get the total resistance and then just use Ohm's law to see what voltage drop you should get worst case, say at 10 amps. 

But again, before you do that you have to have the means to be able to measure accurately.

Knut


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## Greg Elmassian (Jan 3, 2008)

EXACTLY what Knut said... ditto ditto ditto... 

Your wire is not heavy enough, and your topology (wiring scheme) for delivering 10 amps to a train. His point about the voltage drop is very important, those amp ratings you are quoting are for 110v ac supply, not 20v ac.... too much voltage drop. 

If it was me, I'd upgrade the wiring. You could also buy a second booster and second power supply and split the layout into 2 power districts, that's actually an inexpensive alternative. I thing the second booster is like $150 and the meanwell can be had for $70-80.

In my case, even with 10 gauge wire right up to the rail clamp, and direct individual runs from each feed point to the booster, I am setting up for THREE boosters, 1 for each main line and 1 for the switchyard. 

Greg


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## Peter Brayshaw (Jan 28, 2009)

I just spoke to Larry at NCE. They told me that the unit will run at full voltage and full amps and does not limit itself. It can put out 21-22 VDCC at 10 amps continuously. He said it is actually capable of higher amperage (and sometimes voltage) but will shut down once the unit gets too hot. 

He also confirmed that my multimeter is measuring track votage correctly. I set my voltage by two points on the board inside the booster. This is a DC voltage. He said the track voltage will be about 1 volt less on the rails, which is what I measured. Plus the performance of the trains is proportional to the amount of voltage on the rails. That is to say with my old TE system i used to get about 18V to the rails. The trains now run at the same speed, but I have about a 3V loss through the decoder. Greg the reason I have my voltage set high is because at lower voltages the drop throgh the command station and decoder is enough to effect over all performance. Even on rollers on a test track where I know the wiring is in tact. 

As far as the wiring goes running multiple leads or one lead with feeders coming off it is essentially the same thing. I confirmed this with NCE, Tonny's and a fellow ECE friend of mine. 

The only thing i have not been able to accurately test is to see if there is a voltage drop as a train passes. Or if there is a voltage drop once things are moving. I know under normal conditions there is none. By normal I mean 2-4 locomotives. I have done lots of testing and never seen any significant drop. I should try and measure it while the system is maxed out. 

This weekend/ tonight I will put my 6 locos on the rails and check voltage at the tracks as a train passes, at the PSU, and out of the booster. 

I don't want anyone to think I am trying to argue. I really do appreciate the information you guys are giving me, and I am exploring your suggestions as much as possible as well as doing my own research behind the scenes. 

One thing I was mistaken about was the draw of each loco. I always thought they pulled 1-1.5 amps each. I based this off of readings from the amp meter on my elite psu. Last night one thing I learned was that this amp meter is way off. With six locos at full throttle it reads 5-6 amps which is not correct. The locomotives are pulling more like 2 amps each, which is 12 amps which is above what the system is designed for. They pull more then 2 amps when they accelerate. I observed this by watching the multimeter spike as I turned up the throttle, then slowly come back down and level out after a few moments. 

-Pete


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## krs (Feb 29, 2008)

Posted By Peter Brayshaw on 01 Jul 2011 11:15 AM 
I just spoke to Larry at NCE. They told me that the unit will run at full voltage and full amps and does not limit itself. It can put out 21-22 VDCC at 10 amps continuously. He said it is actually capable of higher amperage (and sometimes voltage) but will shut down once the unit gets too hot.


>>> Pete - Did you tell Larry that you're powering the system with 27 Volts DC?

I have no doubt that the system will provide the full 10 amps at whatever the maximum design DCC voltage is, but the NCE manual states that for the 10 amp system one should use an 18 volt AC transformer and that the absolute maximum input voltage is 22 Volts AC.
From a peak voltage point of view, 22 volts AC will have a higher peak voltage than 27 volts DC, but from a power dissipation point of view it's a different story.
NCE doesn't specify that one can use DC as the input voltage to their Command Station but Greg does, so the CS can handle - question is up to what voltage difference between input and output.> Measuring the voltage with a DC meter on the inside of the NCE unit is fine. I still doubt that you have a meter than can accurately measure the DCC voltage on the track. NCE states in their manual that even a True RMS meter cannot measure the DCC voltage accurately, I was a bit surprised to read that - if the True RMS meter is spec't to the DCC frequency (some are only good to 400 HZ) then it can measure the DCC voltage accurately enough for all practical purposes.

Anyway, if some of your locos slow down when you add more locos on the track, the DCC voltage has to have dropped, no way around that.
Question is why and where - does the output of the NCE CS drop or are you getting large voltage drops in the wiring.> I'm not 100% sure I understand what you mean, but if you mean is running multiple 14 gauge leads from the Central Station to various parts of the layout vs running one 14 gauge lead around the layout with short 14 gauge feeders coming off it, that is definitely not the same at all.


....Boy, I'm having trouble to quote and then comment.


Let me look at the rest separately


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## krs (Feb 29, 2008)

Posted By Peter Brayshaw on 01 Jul 2011 11:15 AM 

One thing I was mistaken about was the draw of each loco. I always thought they pulled 1-1.5 amps each. I based this off of readings from the amp meter on my elite psu. Last night one thing I learned was that this amp meter is way off. With six locos at full throttle it reads 5-6 amps which is not correct. The locomotives are pulling more like 2 amps each, which is 12 amps which is above what the system is designed for. They pull more then 2 amps when they accelerate. I observed this by watching the multimeter spike as I turned up the throttle, then slowly come back down and level out after a few moments. 

-Pete 



Pete -

How about the make and model of the meter you are using to measure DCC voltage?
If it's not a "True RMS" meter with a frequency response out to 10KHz or better, it will not read the DCC voltage correctly.


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## Greg Elmassian (Jan 3, 2008)

Thanks for the information Peter, sounds like you are clearing out the issues. 

Yes, measuring the voltage inside the booster will give you a good estimate of the DCC voltage to the rails, although this is the first time I have heard that the rails are a volt less. Larry is the guy, though, so what he says is normally 100% right. 

I completely concur with your higher voltage, as you probably know from my web site, I had to determine the 3 volt drop from DC input to DCC output, and also how to get my unit modified to go over 20.1 volts output. I can get pretty close to 24 volts to the rails. 

But if your system is not modified, you will most likely only get 20 to 21 volts to the rails, and with a regulated power supply, only need 24 volts input. My point is that anything over 24 volts input will be wasted, and converted to heat. 

Since you are running the unit close to it's maximum (and I mean it's maximum output to not overheat) then it's not wise to run more voltage. I've considered putting some heat sinks on the back of the case... the only cooling the booster gets is radiation from the case, there are NO heat sinks on the unit... 

Yep, you need that RampMeter, and connect it to your booster output, you can see how many amps you are drawing. My locos on heavy grades and heavily loaded can pull 2.7 amps each. That is really close to wheel slip and 50 cars on a 3.4% grade. 

The NCE system is (unlike other systems) conservatively rated, and, kept cool, will put out 10 amps all day without complaint, and as you have found, over that... 

Regards, Greg


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## Peter Brayshaw (Jan 28, 2009)

One thing I should clarify is I only get slow downs when I run over 4 locomotives. In this case 6 (I haven't tried 5). I ran run 1, 2 , 3 ,or 4 locos all day long with no issues. That is the other thing that makes me think its a lack of amps more then voltage issue. 

Krs, 
Yes I did tell Larry that I was using 27VDC 13 amps in. The front of my unit says "Max input. 18 V AC/ 32 V DC". I believe my manual says that too. Larry confirmed the unit can handle it. I know previous versions of the booster did not allow for this from the factory and had to be modified. 

As for my multimeter is is a Radio shack brand, I will have to dig out the model number. I purchased it because I used the same one while I worked in a music studio for a short time. It was very accurate and versitile. We had all sorts of voltages and signals and it worked great. 

Greg, 
I see your point about extra voltage being wasted. I will try turning it down this weekend and see how things work. 

If money was no issue, I would invest in the Gwire system tomorrw. Put a big 22 V 20 amp PSU directly to the rails and run the QSI decoders with the reviever upgrade. However I can't afford $250+ per loco to use DCC. I use digitrax decoders because they are decent quality and only about $55 a pop.


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## Greg Elmassian (Jan 3, 2008)

On the previous boosters, 27 volts was the maximum... I've had a number of friends contact NCE about getting their systems modified to output 24 volts (requiring at least 27 volts in), so maybe they changed the design a bit... will have to call Larry. That 27 volts is specified somewhere in the manual, but it was hard to find as I remember. 

Peter, you can get bigger boosters, but when you start putting over 10 amps on the rails (no matter what control system) a short circuit can really melt stuff down. At that point, I think it's wiser (again no matter what control system) to break it down to separate 10 amp power districts. 

If you have ever seen what 10 amps can do to a loco that has derailed, you should try 20-25! 

At some point it just makes sense to go no higher... Just like your house, mostly 15 and 20 amp circuits, not a 100 amp circuit to run all the rooms... there wisdom there... 

Regards, Greg


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## krs (Feb 29, 2008)

Peter - 

I'm having a problem with some of the numbers you posted: 

The front of my unit says "Max input. 18 V AC/ 32 V DC". I believe my manual says that too. 

How does a maximum of 18 VAC relate to 32 VDC? 
If the maximum is a pure voltage constraint (not power as well), an 18 VAC maximum should relate to a 25 VDC maximum (the peak of 18 VAC) 

I also don't understand why you think this is a current (lack of amps) issue rather than a voltage issue. 
If the NCE unit can't deliver 12 amps which is what you are thinking, what do you think happens to the DCC voltage at that point? 
You posted that Larry mentioned that the NCE unit does not limit the current when it gets too hot, so it either delivers 12 amps (or whatever is required by the trains) or shuts down and delivers no current - there is no in-between.


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## Peter Brayshaw (Jan 28, 2009)

Greg,
I do understand the wisdom in to using too many amps and I agree with it. I have a tendancy to want to make things simple... ie one 20 amps supply is easier to hook up then 2 10 amp supplies. That said I don't want to melt my trains either.

I think the best option is to invest in a second PSU and a second booster. I considered buying a one bigger 20 amp psu and using two boosters but I have heard there can be issues with that sort of set up.

krs,
I couldn't tell you how a maximum of 18 VAC relate to 32 VDC. That is what the the unit is rated for. That is to say I can use up to an 18V AC psu or up to a 32 V DC psu to power the system. I am not sure what you mean by asking how one relates to the other. 

For the voltage all I can say is I have not observed any voltage drops and I have checked. And if the voltage is dropping its not doing so durring operating conditions at or below what the system is rated to. 

I only get poor performance when I push the system above and beyond what it is rated for by drawing too much amperage. That is what leads me to believe it is a lack of current, not voltage causing the issue.

I just got some more batteries and fuses for my multimeter. I will double check the voltage all around the rails, and coming out of the booster and psu and check to see if it drops at all.

-Pete


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## krs (Feb 29, 2008)

I just got some more batteries and fuses for my multimeter. I will double check the voltage all around the rails, and coming out of the booster and psu and check to see if it drops at all. 

Just measuring the voltage around the layouts won't tell you anything. 
You need to draw current, preferably close to the 10 amps. 
No current, no voltage drop - Ohms law, E=IR, if I=0 then E (voltage drop) will be zero no matter how high the resistance is. 

What's the model number of the Radio Shack meter? 

Knut


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