I'm looking to include two voltage meters on a control panel to indicate the output voltage of my old Lionel transformer. I'd prefer them to be digital, but I can't seem to find any that are on the 0-25 (ish)V range. I have found some, but they start confusing me with AC and DC input. I have found the following, but have no idea if they'd work.
Any help on finding them would be greatly appreciated.
Thanks.
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Good morning Mike:
I've run into this baracade before as well for other related applications. I know of some good ones (Datel, Murata), but they are north of $60, which doesn't seem worth it for that application. For a quick and dirty reading, there are a wealth of AC panel meters on eBay that would work, but they are all direct from China.
May I recommend an analog meter from a stateside dealer? I've dealt with Robert on several occasions, and he has been a top notch seller with good parts. I have this exact meter on my control board, and it works just fine.
--NMM
This one will work, same seller as your first choice, but a different range choice. You can power it (them) with a 9 vdc battery or a wall wart between 8 to12 vdc. You probably cannot use a power supply for it with the same common lead as what you are measuring (the track voltage, etc.).
You're also going to have to set the range on that one above to 199.9 full scale to see voltages over 20 vac. It looks to be a selectable range...19.9 or 199.9. If so you can switch with a toggle if it suits your application.
This one looks similar but half the price...
I used the 0-200vac meters similar to the ones cjack linked above in my voltage car. They work well and have been going strong for a couple of years now. Readings are pretty accurate too. Got them on ebay for about $5-$6 each, free shipping from Asia. I haven't looked at them for a while, not sure what is now available?
The voltage car was a copy of GRJ's and he helped me with it. As cjack also says above, I had to add DC-DC converters to isolate the track power from the volt meter power. GRJ steered me to a suitable device from Digikey. An AC to DC power converter will not work (don't ask me how I know this). The 9 volt battery powered one cjack noted sounds good and wouldn't need the DC-DC converter.
I have been looking for an AC digital amp meter without much success. What I would really like is one of those all-in-one volt/amp/power meters, but I haven't been able to find one of those either.
I found the meters I used in my voltage monitoring car on eBay some time back, but when I search nowadays, I can't seem to lay my hands on digital meters of the correct range, most are for over 100 volts. As mentioned above, most of these meters require a fully isolated power supply for the internal electronics. While you can do this with batteries, that's kind of a kludge , at least IMO. If I'm powering from track power, the last thing I want is to have to worry about batteries.
If you must use a battery in a mobile unit, consider a relay to only power the meter when the measured power is available, that will greatly lengthen the battery life. 
When I made my voltage car...and is also my distance traveled car...I used a battery. The car is not a finished look. Just a frame. Test car. I just swiveled the 9 v battery connector in place or off. The battery lasts thru it's date range.
I went for the "finished" look. Mine has a isolated power supply for the meters, meters on each side.
Good lookin'
Needs some snappy decals, just haven't gotten around to that.
cjack posted:You're also going to have to set the range on that one above to 199.9 full scale to see voltages over 20 vac. It looks to be a selectable range...19.9 or 199.9. If so you can switch with a toggle if it suits your application.
This is in a foreign language to me... can you dumb it down at all?
rtr12 posted:The voltage car was a copy of GRJ's and he helped me with it. As cjack also says above, I had to add DC-DC converters to isolate the track power from the volt meter power. GRJ steered me to a suitable device from Digikey. An AC to DC power converter will not work (don't ask me how I know this). The 9 volt battery powered one cjack noted sounds good and wouldn't need the DC-DC converter.
....also in the same language as above. So I'd need the DC-DC converter for what? How would the meter read the voltage if it was isolated?
gunrunnerjohn posted:I went for the "finished" look. Mine has a isolated power supply for the meters, meters on each side.
Pretty neat boxcar you got there, John! So if you aren't using the batteries (I agree, sort of don't want to go that route, no offense to anyone) what are you using as an isolated power supply? I guess I'm just having a hard time visualizing all of this.
Thanks guys, for your continued help
Ok on my paragraph, they say 199.9 VAC but the meter shows 00.0. So that is not the right meter or the right picture. Because that meter would only go to 19.9 or possibly but not likely 99.9. So there is either a way to change the range, which I doubt now, or the meter actually goes to 199.9 and it's just a generic picture.
You need an isolated supply to power the meter. It cannot read a voltage and at the same time be powered by the voltage it reads. Think pocket multimeter...it has a battery inside. It doesn't power up from the voltage it reads.
cjack posted:You're also going to have to set the range on that one above to 199.9 full scale to see voltages over 20 vac. It looks to be a selectable range...19.9 or 199.9. If so you can switch with a toggle if it suits your application.
This one looks similar but half the price...
I will be very interested to hear the outcome of someone ordering this particular meter. I have ordered it from Clever Edgar and from Go Carol on Amaze-me-on and every time I get a 0-200V meter that is DC. It says DC on the meter display when powered up and it clearly says DC on the outside of the box. The appropriate check box for an AC meter is clearly not marked. The meter does a good job of measuring DC but will not measure AC which is what both Amazon ads describe in detail. All you get is a partial refund on something you didn't need. Your alternative is to ship it back for more than the thing costs in the first place.
Good luck.
I have had that happen on ebay. I ordered an ac volt/amp meter and got a dc one. I asked for a refund and got a runaround. I finally created a use for the dc one in powering my Miller signs.
This post got me to looking around for the combo volt/amp meters again. I see what GRJ was talking about above now, anything in AC for our trains voltages/currents is hard to find. If the ones cjack linked from Amazon are really DC, that leaves me with finding none so far. They were all over ebay a couple of years ago when I was copying GRJ's voltage car. Wonder why these are so scarce these days? They seem to only have AC in analog meters, no digital.
I always have to brag about Gunrunners voltage cars. I was lucky way back to get him to fix me up with one.
It's a very nice set up.
A 50' Lionel Box car .
Larry
The market seems to be for AC line voltage, above 80 VAC or so. I can't think of any 0 to 25 VAC markets other than the toy train just off hand. You could rectify the AC to peak voltage and then scale it down to RMS by dividing by root 2 (1,414). And use the DC meter. That is only good for pure sine waves like pre and post war transformers, but also pretty accurate for 18 VAC full scale on the modern ZW-C. That is roughly how the less expensive multimeters do the AC. And I am guessing how the Lionel ZW-C meter does it.
Many of the "A/C" meters on eBay are actually DC meters. I got several sets, in all cases they ended up simply refunding my money. I have a few DC meters in my parts drawers now. 
I finally did get proper AC meters for my car, but I haven't seen them since when looking for them.
Yes, they are pretty scarce now. Guess I (we) got in on that one at just the right time. 
Funny thing that there were quite a few back then and then they just dried up.
Here's a picture of my voltage car. The volt meters are 0-200 vac from ebay. I believe they needed 9-12 vdc for power.
And here is a picture of the AC-DC converter (with the green wire terminals). The white 4 wire harness with red, black, yellow & white wires to the right of the AC-DC converter is connected to the DC to DC converter (small black box below connector) that GRJ guided me to in order to make everything work properly and prevent any unexpected smoke releases.
That was built about 2-1/2 years ago and it's still going strong, works great. It was a fun project.
I think I have a wiring diagram for the voltage car. I'll see if I can find it tomorrow and post it here. Might give you a little language translation. It's hand drawn though, probably not the best schematic appearance wise, but it works.
That looks pretty involved rtr!
With the analog meters, they can be hooked up directed to the source, correct? No alternate power source needed? I may go that route if the other seems like it is going to be such a pain.
It really was not all that bad, but yes, analog can be connected to track power (between power supply and track) and that is all you need. Analog is what I have on my track power feeds as well. I got those before GRJ showed me his voltage car. The voltage car is the only place I have digital meters. The digitals need an isolated power source, they don't work very long unless it's isolated. I would say no more than just a few seconds...I have a couple of dead ones as proof. Fortunately, they were only about $5-$6 each, so not too bad of a loss.
I think you can also still find the analog versions on ebay or Amazon. I used 0-30 volt and 0-15 amp for the analog meters.
mjrodg3n88 posted:That looks pretty involved rtr!
With the analog meters, they can be hooked up directed to the source, correct? No alternate power source needed? I may go that route if the other seems like it is going to be such a pain.
The analog meters are a bit hard to see across the layout. I have digital meters on both sides of the car so I can see the voltage anywhere. I think it's probably worth the trouble.
Basically, you wire the track power into the input of the AC->DC power supply, you pipe it through the DC-DC isolation module, and that goes to the meter power. The track power also goes direct to the measurement terminals of the meter. It's really quite simple.
GRJ really is correct here, it's really not all that hard. Sounds like it may now be harder to find the meters?
Actually, I thought it was more difficult cutting the holes to fit the meters just right and getting all the things to fit inside without hitting one another when put back together. Wiring was the easy part.
And here is a heretic thought 
, while having an exact track voltage measurement is nice, consider making the car with the digital meter that if unable to adjust it to read exactly, say 18VAC, with your multi-meter, make whatever the car meter reads be your "goto reference". After all, as I understand the car purpose is to spot low voltages or dead spots. So as your car zips around the layout, you will observe that the reference reading is approximately steady, but if it goes low or zero, that will be the area to investigate with your trusty NBS calibrated laboratory multi-meter accurate to six places right of the decimal point .
Even cooler would be a colored light bar on the car.
cjack posted:The analog meters are a bit hard to see across the layout. I have digital meters on both sides of the car so I can see the voltage anywhere. I think it's probably worth the trouble.
I'm sure they would be hard to see! Unfortunately for me, I only have a tiny, 8x10 room, so that shouldn't be a problem.
rrman posted:And here is a heretic thought
Good point, BUT... something I should've originally noted, this will be for reading accessory voltage coming from an old Lionel KW.
gunrunnerjohn posted:Even cooler would be a colored light bar on the car.
Now THAT would be cool, John.
Here's sort of a mock-up of what my control panel may look like.
Out of curiosity, what do you use Accessory Power for...that you want to meter the voltage? Presumably you have the two meters measuring the two KW handles. Do you routinely adjust Accessory voltage during operation?
Stan,
I'll be using the accessory power for the Turnout power and for the operational track power (this will be on one of the KW handles.) The other I'm hoping to use (if I can fix it) for lighting on the layout.
I have nothing put together yet, working on that now. I will not be adjusting the voltage, but if a handle is bumped, I want to be able to see it from my panel.
What do TIU VAR1 and VAR2 power on your layout? Are they used in Fixed or Variable mode? If Variable, it seems you'd want to meter those outputs. Or perhaps add a selector switch so your meter(s) can measure them?
stan2004 posted:What do TIU VAR1 and VAR2 power on your layout? Are they used in Fixed or Variable mode? If Variable, it seems you'd want to meter those outputs. Or perhaps add a selector switch so your meter(s) can measure them?
Stan,
My loops are powered through Var1 and Var2. I'm using them in both Fixed and Variable modes (Fixed when running command locos and Variable when running conventional locos.) I'm not sure if using a meter would be necessary when running in Variable since all I'll be doing is controlling the conventional engines. Maybe just to know where the voltage is, but I dont know if that'd be needed.
Some impressive/creative work on the voltmeter cars above.
I think the ultimate voltmeter car would be one that can report back the exact location of a fault or variance in the voltage. Adjustable tolerance levels on the variance would be helpful. The location would have to be referenced to inches past the last installed track sensor.
Future options to be offered on this car would be:
- log a report with the number of inches from the last sensor where the variance was noticed. To be read out on the remote display.
- for century club members, an audio announcement from the car letting you know that you have mail (the variance log report).
- for those members of four or more train clubs, the voice in the audio would be HAL from the 2001 Space Odyssey.
- for those who are members of four or more train clubs and four magazine subscriptions will receive a text to their mobile device as well.
- for those who have bought at least 2 engines out of every manufacturers catalog for the past 8 years: the voltmeter car will stop the train, back it up at no more than 2mph scale speed and stop the train when the voltmeter car is over the variance. The car will then make an announcement with HAL's voice and send you a text.
- for those who post that they are already working with Douglas Rain on this car, well . . .
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