gregc i believe most modelers don't have panel meters, they're just not necessary until there's a problem. i believe the most common problem is voltage drop either due to a bad wire connector or rail joiner. these can easily be diagnosed with a meter regardless of accuracy. just the difference in measurements between different track points is needed. on the other hand, a current meter can't be used as easily as a voltmeter. but adding a set of bananna plugs and strap between them during normal use would make it easy to use a current meter. such jumpers could easily be added for each power district i don't know what an RRampMeter can do that a good digital meter can't
i believe most modelers don't have panel meters, they're just not necessary until there's a problem.
i believe the most common problem is voltage drop either due to a bad wire connector or rail joiner. these can easily be diagnosed with a meter regardless of accuracy. just the difference in measurements between different track points is needed.
on the other hand, a current meter can't be used as easily as a voltmeter. but adding a set of bananna plugs and strap between them during normal use would make it easy to use a current meter. such jumpers could easily be added for each power district
i don't know what an RRampMeter can do that a good digital meter can't
My previous post was addressed to lastspikemike who, at least intially, didn't see a need for any type of meter. "Your system either runs the trains or it doesn't".
Rich
Alton Junction
Rich, I saw your thread about testing your engine facility, https://cs.trains.com/mrr/f/744/t/285033.aspx.
As I said in starting this thread I don't understand how this electrical stuff works under the hood. Can you explain in simple langauge the need for the light bulb?
Rick
Lastspikemike Nobody so far has explained what one would need to use the current consumed information for. I've asked.
Nobody so far has explained what one would need to use the current consumed information for. I've asked.
hbgatsf Lastspikemike What do you do with the information? Your system either runs the trains or it doesn't. Most of the time everything runs fine. Occasionally gremlins show up. When that happens troubleshooting is needed and I see this as a tool to help. Rick
Lastspikemike What do you do with the information? Your system either runs the trains or it doesn't.
What do you do with the information?
Your system either runs the trains or it doesn't.
Most of the time everything runs fine. Occasionally gremlins show up. When that happens troubleshooting is needed and I see this as a tool to help.
LastspikemikeNobody so far has explained what one would need to use the current consumed information for. I've asked.
Apparently you suffer for SRS (selective reading syndrome). I and several others have given you some examples where the ability to read current draw was helpful in diagnosing an issue with one's track or locomotive.
In my case, the motor of my brass locomotive was running erratically. It wasn't until I viewed the fluctuations in current (i.e. from 0.18A to 0.9A, with spikes as high as 1.7A) with the built-in ammeter of my NCE Power Cab that I realized the motor was bad and/or binding internally.
Could I have come to that same conclusion without reading the current draw of the motor? Sure. However, the ammeter gave me quantitative numbers to compare against what a properly-operating motor normally draws to help me realize that something wasn't right. In another case I could see that there was a short with a decoder install. The current draw was slightly above the trigger point of the circuit protection of the Power Cab but stayed on long enough to view the current draw.
Yep, a pretty handy device and feature to have but perhaps not as important to others...
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
LastspikemikeIf you know your locomotives each draw less than 1 amp then by all means use that lower number to estimate the maximum possible power you may need for any given power district (my DCC layout has just one).
And how are you goint to know what you're locomotives draw without the current consumed nformation?
gregci believe most modelers don't have panel meters, they're just not necessary until there's a problem.
True, they are not necessary, and I don't think anybody has said they are, they can be quite handy though.
gregci don't know what an RRampMeter can do that a good digital meter can't
If by "good" you mean a true-RMS meter, than nothing, but I would be willing to bet most model railroaders don't have a true-RMS meter lying around. If it's not a true-rms square meter, then it won't give you the true voltrage or current of the DCC signal. Do you need an accurate measure of voltage or current? Most times not, but it can be useful information, and if you're measuring it anyway, why no get it right?
Even if you have a true-RMS meter, a purpose built tool can be a lot more convenient.
hbgatsf Rich, I saw your thread about testing your engine facility, https://cs.trains.com/mrr/f/744/t/285033.aspx. As I said in starting this thread I don't understand how this electrical stuff works under the hood. Can you explain in simple langauge the need for the light bulb? Rick
For example, on my layout, the voltage at the booster is 13.5 volts. Without a load, I also measure 13.5 volts at the end of the bus. But, when I add an 1156 automotive bulb on the output side of the RRampMeter, under load the RRampMeter measures 11.3-11.4 volts at the beginning of the bus (actually the rails right at the first pair of feeder wires.
As I move down the layout, every 5 feet or so, I get the following voltage readings under load: 11.2-11.3, 11.1-11.2, 11.0-11.1 etc., all the way down to 10.7-10.8.That is "voltage drop".
The loss of voltage is not that dramatic on my layout, but that is because I use relatively short lengths of bus. On my old layout, I used a continuous loop of bus wire (unconnected at the other end of the loop. I experienced voltage loss at the end of the long bus measuring more than 1.5 volts, resulting in slower speeds of locomotives at that point(s) of the layout.
Lastspikemike Your locomotive wasn't running right. You knew that already. How did knowing the actual current draw help you fix it? Could you not get that same information by measuring directly at the locomotive? So, what else would you use this real time current/voltage display for?
Your locomotive wasn't running right. You knew that already. How did knowing the actual current draw help you fix it? Could you not get that same information by measuring directly at the locomotive?
So, what else would you use this real time current/voltage display for?
Most of us are loan wolf operators. Picture this. I'm doing some switching in my yard with one diesel switcher. All of a sudden it stops no lights no sound no motor. Is an open in the track wiring or the locomotive? Is it a short from a cut of cars on a closed turnout? One glance at the meter will tell you if it's a short or open. So you give the locomotive a push and the lights come on but still no movement. One glance at the meter reads .001 amp. So you push the locomotive a little further and you have sound, lights and motor. Very quickly you have diagnosed a bad solder joint in that track section. Without digging out your multimeter, test truck, and scratched a raw spot on your head.
Now say you have the same scenario. Pushing the locomotive cured the issue until the front truck turned left and it stalled again but came back. The meter jumping in amps but voltage remains constant will undoubtedly lie with a bad connection in the locomotive.
Having the right information is key to successful troubleshooting. I have known guys take their truck into a shop because of coolant in the oil. After a $20,000 engine overhaul the same issue. A proper diagnosis the first time would have shown a leaking head gasket on the $500 air compressor was the culprit all along.
Pete.
Lastspikemike You don't need to know that. All you need to know is the locomotive runs badly. Take the shell off and find out why. Although, I have an open mind if somebody wants to explain why you need to know anything other than the locomotive isn't working. These are very simple machines. Very simple. Wire them correctly and they will run. Mechanical problems are the motor is bad or the gears broken or incorrectiy aligned.
You don't need to know that. All you need to know is the locomotive runs badly. Take the shell off and find out why.
Although, I have an open mind if somebody wants to explain why you need to know anything other than the locomotive isn't working.
These are very simple machines. Very simple. Wire them correctly and they will run. Mechanical problems are the motor is bad or the gears broken or incorrectiy aligned.
LastspikemikeYou don't need to know that. All you need to know is the locomotive runs badly. Take the shell off and find out why. Although, I have an open mind if somebody wants to explain why you need to know anything other than the locomotive isn't working. These are very simple machines. Very simple. Wire them correctly and they will run. Mechanical problems are the motor is bad or the gears broken or incorrectiy aligned.
I'm not talking about locos that run badly. You can have a very wide range of current draw for locos that run well. Say I've got 5 amps and I want to know how many of my locos I can run at a time. Well, it's going to depend on how much current the locos draw. Sure, I could just add locos until the booster trips, but since different lcos draw a different amount, it's likely going to depend on which locos I choose. If I did a test and could run 10 locos, but I happened to choose all low current draw locos, if I throw in a few higer current draw locos the next time around I may not be able to run as many.
Lastspikemike So two reasons: maybe helps diagnose a poorly running locomotive and helps you initially size your powerpack. Any other reasons to acquire these devices?
So two reasons: maybe helps diagnose a poorly running locomotive and helps you initially size your powerpack.
Any other reasons to acquire these devices?
How about using the RRampMeter to check for voltage drop? So, now, three reasons.
The current varies with load on the motor both in DC or DCC modes. A single locomotive running on level track by its self draws very little current. As you add cars the current increases then through in a grade with cars it increases even more.The ammeter shows the amount of power needed to do the job. Very few locomotives draw the same amount of current needed. Driving a car is different from model railroading. The way one determines how much power a car takes is at the gas station. On my layout I monitor the ammeter to see how much power a locomotive takes. Much like blood pressure, some never check it, I do. Like high blood pressure can be very bad so can high current in a motor.My era is the 1950s with a mix of steam and diesel, no two are the same. Most have been remotored using neodymium magnet motors, some with dual motors. I find that monitoring the current of my locomotives gives me some insight on their operating status, you know, the warm and fuzzy feeling that everything is OK.
Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California Turned 84 in July, aging is definitely not for wimps.
See my previous post.
CSX RobertIf by "good" you mean a true-RMS meter, than nothing, but I would be willing to bet most model railroaders don't have a true-RMS meter lying around.
my understanding is that it's the frequency range of the meter. many are intended for measuring house voltages at 60 Hz. i understand why some modelers are better off with the RRampmeter
richhotrainThe purpose of the automobile bulb is to test for voltage loss along the layout. The automotive bulb tests for voltage "under load".
the bulb doesn't test for voltage, the bulb provides a load (~2A for an 1156)
greg - Philadelphia & Reading / Reading
LastspikemikeYou don't need to know that. All you need to know is the locomotive runs badly. Take the shell off and find out why.
one way to find out is to measure the current drawn and the voltage on the motor.
it would be helpful to know what the motor draws when running correctly
gregc richhotrain The purpose of the automobile bulb is to test for voltage loss along the layout. The automotive bulb tests for voltage "under load". the bulb doesn't test for voltage, the bulb provides a load (~2A for an 1156)
richhotrain
The purpose of the automobile bulb is to test for voltage loss along the layout. The automotive bulb tests for voltage "under load".
gregcmy understanding is that it's the frequency range of the meter. many are intended for measuring house voltages at 60 Hz
It's as much the wave shape as it is the frequency range of the meter. Most multimeters measure the avergae voltage and are calibrated to give the correct RMS reading for a sine wave. The relationships between average, peak and root mean square voltage are different bewteen a sinewave and a square wave.
CSX RobertIt's as much the wave shape as it is the frequency range of the meter.
a meter designed to measure 60 Hz would certainly have a problem measuring a sine wave at DCC frequencies
DCC is ~10kHz. the harmonics of a square wave easily require 3x that.
CSX RobertThe relationships between average, peak and root mean square voltage are different bewteen a sinewave and a a square wave.
they are all different for a sine wave, but they are the same for rectified a square wave (i.e. Vpk = Vavg = Vrms).
if you account for the drop thru a bridge rectifier (~1.4V) you should be able to very accurately measure DCC with a DC meter.
this is probably what the RRampmeter does.
gregca meter designed to measure 60 Hz would certainly have a problem measuring a sine wave at DCC frequencies
True, I did not say the frequency was irrelevant, I said the issue is "as much" the shape as the frequency. If the meter was designed for a 10khz sinewave it would still be incorrect.
LastspikemikeYour locomotive wasn't running right. You knew that already. How did knowing the actual current draw help you fix it? Could you not get that same information by measuring directly at the locomotive?
With the ammeter in my Power Cab I get a more accurate reading because it's specifically designed for measuring DCC current (vs using a DMM that measures only DC & AC voltage & current).
With the brass locomotive up on the rollerbearing stands and the shell removed, I could visually see the motor struggling and binding. The motor housing also became very warm to the touch. What I could not determine the extent of is how much (quantitatively) the motor was struggling in terms of current draw.
Visually watching the fluctuations in the current confirmed that there was some sort of internal binding going on inside the motor housing, which is generally a sign that an electric motor is bad or going bad. Squeezing the motor housing slightly also showed me how that affected the operation of the motor - good & bad.
When I installed the replacement (coreless) motor, I wanted to see how much current it drew in respect to the LokPilot 5 decoder. As mentioned on pg. 1, at speed step 001 the motor was drawing only 0.02A. At speed steep 030, it had only increased to between 0.04-0.06A. That confirmed to me the replacement motor was operating very efficiently and well within the acceptable range for the decoder.
If you'd like to read the details and the troubleshooting process, you can go to this thread posted back in Aug '21, which, ironically, you commented on no less than 4 times...
To all posters except spike totally agree and if someone wants a tool of anykind for their rr then get it I know I do
Back when I was a maintainer for the real rr I could get just about anything I needed
Don't forget you are dealing with a narcissist / egomaniac and that's just my opinion I might get banned for that one kinda like Kevin did for speaking out on the forum expert ;
mikeGTWDon't forget you are dealing with a narcissist / egomaniac
+1
He sure has taken away the enjoyment of my participation in these forums.
Thanks for speaking up.
[edit]
Forgot to mention one other nice feature of the RRAmp meter and that's the simple LED to indicate a DCC signal present. There are times when there's voltage on the rails but no DCC signal present. One glance at the meter will confirm this.
https://www.youtube.com/watch?v=HMxPKlafoCo
Regards, Ed
gregc CSX Robert If by "good" you mean a true-RMS meter, than nothing, but I would be willing to bet most model railroaders don't have a true-RMS meter lying around. my understanding is that it's the frequency range of the meter. many are intended for measuring house voltages at 60 Hz. i understand why some modelers are better off with the RRampmeter richhotrain The purpose of the automobile bulb is to test for voltage loss along the layout. The automotive bulb tests for voltage "under load". the bulb doesn't test for voltage, the bulb provides a load (~2A for an 1156)
CSX Robert If by "good" you mean a true-RMS meter, than nothing, but I would be willing to bet most model railroaders don't have a true-RMS meter lying around.
richhotrain The purpose of the automobile bulb is to test for voltage loss along the layout. The automotive bulb tests for voltage "under load".
I think we have two ships passing in the night here. There's the light bulb testing appliance, with pigtails, just to see if the rails have power, and there's the light bulb to prevent letting the magic smoke out of decoders in the affected area if there's hard short.
In the first instance, you quickly determine that you have power to the rails, so why is 'effect X' happening...a stall, intermittent performance in one or more locomotives in that spot....that kind of thing. In the second instance, you have a permanent in-line installation of the 1156, fascia mounted, and when it glows you know you have a short in it's controlled space. The reason people use it, apart from taking up the current and sparing decoders nearby, is that it lets the rest of the layout continue to operate if the total current draw isn't going to go into overload territory with the light bulb glowing.
And, even further, that is why some prefer a buzzer/ringer device over, or in addition to, the 1156 because if other unaffected locomotives continue to operate, especially if they're 'noisy', a person with her/his back to the 1156 might not realize he/she needs to clear a short.
doctorwayneAh, thank goodness for the simplicity of DC.
It is always good to know if one is over taxing their power supply. A unit might be able to work fine at 10% or 15% over capacity, but it is going to burn out sooner. As a kid I killed my original MRC Ampac that way (silly kid running 6 locos at a time. Not our nice low current draw ones but the 1960's vintage type).
selectorI think we have two ships passing in the night here.
Well, let me throw a tugboat in the mix, too.
The idea of an automotive lamp is to provide some kind of load while reading voltage across the rails. Without a load it is easy to read nearly even voltage no matter where you place the meter leads.
Once you clip a lamp, acting as resistance, on the test leads OR on the other end of the RRAmp meter you have introduced the potential for showing where the weak point of your track, feeders, joiners or point contact areas are.
I just ran into a similar situation with my 230V electric baseboard thermostat. I wasn't getting any heat in the room and the cheapest fix was to replace the line-voltage thermostat. But in testing it I was getting 230V at the heater and I was getting continuity across the contacts.
I went ahead and replaced it anyway. Once I ground the rivets off and opened up the old thermostat I could see why I wasn't getting any heat. One contact was nearly burned off. Still there was enough of a surface to allow 230 V. to get to the meter but under a 20 amp load of the heater, no dice.
Same with a model RR. You can have a dirty rail joint that may allow your meter to read the same, or very close, to what your source is but once you introduce a load, boom, there goes your continuity.
Go to page 4 here:
http://www.tonystrains.com/download/rramp-appnotes-df.pdf
"Nickle Silver rail is not as good a conductor electricity as copper wire and can be a significant part of the voltage loss. Rail joiners can also cause a loss in voltage. To determine the layout voltage loss the voltage must be measured at the rails when current is flowing. Without a current flow there is little to no voltage loss. It is almost impossible to get a good stable voltage reading using a train running as a current load. The best way to measure the loss is with some type of steady load. An automotive lamp turns out to be a good device to use as a steady load. They are cheap."
Goos Luck, Ed
gmpullmanThe idea of an automotive lamp is to provide some kind of load while reading voltage across the rails. Without a load it is easy to read nearly even voltage no matter where you place the meter leads. Once you clip a lamp, acting as resistance, on the test leads OR on the other end of the RRAmp meter you have introduced the potential for showing where the weak point of your track, feeders, joiners or point contact areas are.
This was very helpful information. Thank you!
It explains why when I was testing my mainline for voltage fluctuations with nothing running on the track I wasn't seeing any difference on my mulitmeter on any point on the track. I found it frustrating because I was getting slowing / hesitating locos at these points so the unchanging multimeter readings made no sense to me.
I will use this techique from now on for troubleshooting. Thanks!
- charles
gmpullmangmpullman wrote the following post 15 hours ago: mikeGTW Don't forget you are dealing with a narcissist / egomaniac +1 He sure has taken away the enjoyment of my participation in these forums. Thanks for speaking up.
Mike
gmpullman Without a current flow there is little to no voltage loss. It is almost impossible to get a good stable voltage reading using a train running as a current load.
Without a current flow there is little to no voltage loss. It is almost impossible to get a good stable voltage reading using a train running as a current load.
Is that because of the low power requirements of a single locomotive?
hbgatsf gmpullman Without a current flow there is little to no voltage loss. It is almost impossible to get a good stable voltage reading using a train running as a current load. Is that because of the low power requirements of a single locomotive?
the current drawn by the loco varies. the auto bulb current is consistent.
as rich explained, the voltage drop depends both on the resistance and current, so any problems will be easier to measure with a higher load
nickle-silver rail ir roughly equivalent to 26g wire
richhotrainI own three RRampMeters,
is there a difference in votlage measurements between your RRampmeters?
i wonder how well calibrated RRampmeters are and how well they stay in calibration. Qualcomm calibrated all lab equipment twice a year.