OK. I got my new Multimeter. Now the questions. I do not use a booster on my 10'X16' layout. It has always run fine. I now have a couple of spots that my Broadway decides to slow up my it self.
How do you check the DCC voltage at the track using my new meter? Setting( AC ,DC, Placment of Red & Black probes Etc.) What should this voltage be?
How do you check the drop in voltage? Do you have to put a load on? If so how do you put a load on?
Do you need to check Amps on a DCC layout?
Please keep as simple, this will be the first thing I do. Thanks in Advance
Set the meter on the 200 Volt AC range. It doesn't matter which color probe is placed onto which rail. You should get a reading of around 14.5 to 15.0 Volts AC. Without a train running through the area where it slows down, the measured voltage probably will not drop. You need to take the voltage measurement as a train is running to get a more accurate indication of voltage drop.
To conduct an Amperage draw reading, you have to remove one of the track feeder leads and connect the meter so all of the current is flowing though it. Set the meter dial on 10A and move the red probe to the 10ADC socket.
The DCC systems I know of all use AC on the track. You will need to check with you owners manual to see what it should be.. I use the MRC wireless and it use 14.5 volts AC. To measure this set the meter for the proper AC range and connect the leads of the meter to the track. With AC it does not matter which lead goes on which track. I would if possible take a measurement straight from the Command Station or as close to it as possible to get a reference voltage. Then try on the place where you are having problems. The voltage should be the same everywhere on the track.
As far as a load just running an engine will do. I am not sure what that would tell you as I do not know what an acceptable drop in voltage would be. I would suspect the more load the greater the voltage drop. If the load is to much the command station should shut down, If there is voltage drop along the track i would suspect the wiring is the problem , not a heavy enough gauge etc.
I know this is not all the ansewers to you questions , but its a start.
Hope it helps a little
Hal
IIRC (will probably get corrected) you need to use the AC setting. you should see close to what your DCC system puts out (~14v AC or so -- might be a touch off since this isn't sine-wave AC like the meter is expecting).
voltage drop is just check spot A (say right next to the booster/command station) and then compare to spots B,C,D, etc. they should all be the same (or very close). the difference is your voltage drop.
amps just measure the total capacity of your system -- if it puts out 2 amps (NCE Powercab, Digitrax Zephyr) you can't run anything totalling over 2 amps. This can be any combination of things, for example:
If you've bought all "DCC Equipped" locomotives thus far, it's a safe bet that they're using can motors, and pulling about 0.1 amp at full load. If you've got older locomotives that were DC-only open frame monsters (anything built by Bowser, for example) you'll have to test their draw as follows:
this doesn't account for any switch machines (~0.2 amps for tortoise) or the like.
-Dan
Builder of Bowser steam! Railimages Site
I am in the process of changing a 35 year old Brass engine from DC to DCC. Am I better off also changing the motor?
Would't my MRC booklet give me the output for the Amps? Is there any other reason I would have to measure the output with my meter?
Put the meter away and do a quarter test on the whole layout. If there is a spot that slows the locos that indicates that more wiring or soldering of joiners is in order. A quarter test will indicate if the booster is putting full power to the spot where your having trouble. If the booster does not shut down instantly then you know there is a problem. A voltage check will only tell you if you have power to the section not how much power it has.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
hwolf OK. I got my new Multimeter. Now the questions. I do not use a booster on my 10'X16' layout. It has always run fine. I now have a couple of spots that my Broadway decides to slow up my it self. How do you check the DCC voltage at the track using my new meter? Setting( AC ,DC, Placment of Red & Black probes Etc.) What should this voltage be? How do you check the drop in voltage? Do you have to put a load on? If so how do you put a load on? Do you need to check Amps on a DCC layout? Please keep as simple, this will be the first thing I do. Thanks in Advance
I use the below adapter. The meter is a cheap digital one I bought from Harbor Freight for about $3.00. Many, the same size but different case are available on ebay.
I have three of these meters that compare very closely to my expensive meter. If I drop or burn out the cheap meter through incorrect use, guess the price to replace the meter.
The voltage is a few tenths of a volt different than without the adapter so it should be good for general DCC use but some meters may differ on the voltage you see.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
hwolf I am in the process of changing a 35 year old Brass engine from DC to DCC. Am I better off also changing the motor? Would't my MRC booklet give me the output for the Amps? Is there any other reason I would have to measure the output with my meter?
You would be better off to start a different thread for the brass loco. The discussion could get lost in this thread.
When our club converted to DCC with a layout that has 14 blocks, we found the meter very helpful as some blocks differed in voltage and loco response was slow. The meter allowed us to see the issue quite rapidly. We usually ran only one or two DC locos in different blocks which was not much current before converting.
A poor feeder connection would show this also. Say only one or two strands of a #22 feeder were connected because of incorrect soldering, there could be quite a voltage drop. If you know your layout is wired correctly, probably not an issue but don't forget, Murphy.
The amount of amps with depend on how many locos and other stuff on the layout. Voltage is always there, if nothing on the layout, no amps drawn from the DCC controller.
Our club uses a DCC amp meter that constantly measures and displays the amps on a meter high on the club wall for all to see quite easily. We sometimes run as many twelve sound locos.
hwolf I am in the process of changing a 35 year old Brass engine from DC to DCC. Am I better off also changing the motor?
maybe. depends on how good the current motor is.
hwolf Would't my MRC booklet give me the output for the Amps? Is there any other reason I would have to measure the output with my meter?
most likely the amperage rating is listed in the book (IIRC, MRC is a 5-amp system). Note that amperage isn't like voltage (insofar as it being "output" by the DCC system) -- it's the rated capacity that the system can provide. The test I explained was to determine what the _draw_ of the locomotive is, when the wheels are slipping.
EDIT -- as rich mentions above, Amps are being "consumed" by the locomotives, Volts are not. Provided that everything is hooked up properly, you should read the noted 14-15 VAC (nominal) everywhere on the track, regardless of load being placed on the system. The Amp draw is what needs to be monitored -- either through simple math calculations as my example below, or through some form of integrated ammeter between the DCC booster and the track.
since this is an old brass locomotive you're talking about, it's probably pulling between 0.5 and 1.0 amps (500-1000 mA) at wheel slip (higher if it stalls out -- unlikely, though if you didn't get a screw tight enough and it throws a rod, that'll usually do a great job of stalling the motor). You'll need a decoder that can handle at least 1A continuous, and probably like 1.5A peak.
so, now for the sake of discussion, you have a 5 amp system and one locomotive pulling 500mA. that leaves 4.5A of available power left in the system.
now, this doesn't even factor in other goodies that feed off of track power (lights in all the locos, signal system, etc) -- normally this is pretty negligible, but it adds up as well -- i think that golden white LEDS (look like incandescent bulbs) pull about 10-15 mA per... "standard" 12-16v lamps (ie GOW light bulbs) pull around that, or maybe even a little more)
hwolf I am in the process of changing a 35 year old Brass engine from DC to DCC. Am I better off also changing the motor? ...
...
I agree about getting this question lost in a thread of a different topic. But, to help you, the answer is....maybe. You need to know the most amperage this older motor will want to draw when you are holding the engine tightly against the tracks and have the throttle cranked well up. In other words, you want what is called "stall current". You don't want six seconds worth of stall current...only as long as it takes to get a steady reading...then back off on your grip and let the loco move/spin.
Of course, you will be doing this very carefully so as not to break anything.
If the measured stall current of this motor exceeds the rating for the decoder (they all have a max amp rating before they go poof and let out their magic fumes), you will need a different decoder. Maybe one for O or G gauge, say, and if they'll fit, or yes, you'll need a motor with less draw.
Crandell
If you have to ask the original question then chances are you don't have enough feeders. Over time the rail joiners will begin to break down and won't handle as much current. If you measure the voltage chances are everything will look fine. You have to measure while a loco is present and under load.
Springfield PA
I'm currently shopping for a DCC starter kit, possibly a Zephyr Xtra. It is rated at 13 volts and 3 amps. The amperage is ok but I don't know if 13 volts is enough. What do you think?
Actually you do use a booster on your layout. I believe what you mean is that you do not use a second booster.
If your trains are running fine at normal speed in some areas and slow down in others you need more feeders in the slow areas. You may even have to increase the size of your bus wires to these areas.
Voltage test as already described with a load on the section being tested will show you where those feeders are needed. It could be as simple as a section of track that needs feeders because it no longer makes a good connection with the track adjacent to it (not slodered).
Martin Myers
Ron Hume I'm currently shopping for a DCC starter kit, possibly a Zephyr Xtra. It is rated at 13 volts and 3 amps. The amperage is ok but I don't know if 13 volts is enough. What do you think?
It works for N scale and HO scale. If you are doing smaller scale like Z there are ways to correct the output. Digitrax has an adapter. For larger scales, you would need more voltage then most of the base line starter systems supply.
With my NCE Power cab and the NCE five amp Power Pro at the club we use a Harbor freight multimeter on the 200 v AC scale. We see about 13.6 vac. We put a loco on the track or use a auto light bulb. Load needed to see a voltage drop.
With a couple transistors and a few passive components I made an adapter to read DCC voltage but found out the basic digial meter worked just as well. Found no need for a true RMS meter. Saved money also.
With a couple three terminal devices and few extra components, the meter on the 20 ma DC scale doubles and an excellant inexpensive DCC amp meter.
I have had four of these meters for some years.
If not into messing with components, just get a RRampMeter from Tony's Trains.
The meter can be an extra help if the RRampMeter can not be easily moved. Never used one.
Thanks Martin. I'm into HO so the Zephyr should be ok. I would like to have had two throttles on the console like some other brands, but I guess an extra cab will have to suffice.
Ron.
With Digitrax there is al anternate way to measure track voltage, and that is the reading between each rail and the terminal labeled GND on the system. Each reading will be half the total track voltage and should be equal, added together it si the total track voltage. Use the 20V DC range on the meter for this. If the voltages are not approximately equal (.5 difference or less), make sure you haven't been using the address 00 feature to run a non decodered loco. If you have, select address 00 and make sure the htorttle is at the stop position and the direction handle is in the brake position.
I started with the original Zephyr, and have added a couple of throttles and added a DB150 booster. I usually unw ith the DB150 set to the N scale setting, which matches the 12V output of the original Zephyr. I don't run high speed passenger trains, and all of my HO locos run plenty fast enough on a 12V DCC signal.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.