Anyone have have any thoughts on this volt amp meter for use on a postwar ZW
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The ZW outputs AC. The referenced meters measure DC current.
Bruce
BruceT47 posted:The ZW outputs AC. The referenced meters measure DC current.
Bruce
Yep. 
You could try something like this instead.
Danr posted:You could try something like this instead.
That one won't measure below 100volts. I built a panel last year. I could not find a dual, digital meter that would work. I found separate meters, but it was pretty complicated to power and wire them. There is a whole thread on it.
Can't you find the Lionel meter made for the ZW? I know they are somewhat scarce and a little pricey.
George
Danr posted:You could try something like this instead.
Those meters often start the AC volts at 80 VAC. They are meant for line voltage. This seller doesn't say, I would ask first.
The seller actually does say...
Measuring Range: AC100-300V, AC0-100.0A (with sensor transformer)
So he does! I didn't click on the "View Details".
Thanks...
I wonder what is so hard to start VAC at 5vac or so...maybe the self powered issue of powering and measuring with the same source.
I purchased this volt meter back in 2015. It's fairly accurate (once adjusted against a know good meter). It max's out at 19.99 vac though. Unfortunately it's unavailable on Amazon right now. Maybe some googleing will yield a source.
I've not found a good amp meter for AC under 10 amps.
Tony
One like Recovered linked to above would be neat to have in voltages and ranges suitable for our trains! Unfortunately, like George S, I have not been able to find anything even close. I have been looking on and off for quite some time. Even the individual ones seem to be getting more scarce.
I bought them for my voltage monitoring car several years back, and now they seem to have fallen off the face of the earth. I have a couple of 19.9V models that I scored before they disappeared several years ago.
I have several sets of real nice DC meters that the Chinese tried to pass off as AC meters, I had to insist on a refund for those. 
I bought those too and asked for a refund, but got a run around. So I kept them and made DC supplies and meter for running signs.
Chuck, I insisted. I asked for a return shipping label since they were not as advertised, and of course a full refund. Knowing they probably had about 50 cents into them, they decided to issue the refund and skip the return shipping. I can only imagine what it costs to ship something to China, but I know it's not cheap! Shipping the other way is a whole different story...
First Class mail to China starts at US$13.50.
That's the ballpark I was figuring on. I guess those guys didn't think a pair of $6 meters were worth paying that much to return them. 
I also ended up with a pair of dual volt/amp meters, same deal. They were advertised as AC, and they were DC. Same outcome, I refused to pay for someone else's mistake.
I bought this one. I missed the part in the lower description about 80-500v. The title said 0-500v. They read 30v with 20v on the track. Stored them in the experience file.
I wonder if this meter
http://www.ebay.com/itm/Blue-D...%26sd%3D400888428064
which has the separate power supply (4 wire hookup), actually reads down to 0 Volts AC
This one might have better resolution.
I am NOT proposing this as a solution but simply fodder for discussion for MacGyver fans (the original series).
Self-powered LED digital AC voltmeters mentioned above that operate between 100-300V AC (or whatever) are like DC automotive voltmeters with a narrow operating range. In other words they are application specific.
I don't think the market is large enough for a mainstream manufacturer to produce a digital panel meter for O-gauge AC voltage (or current).
So here's the MacGyver angle. If you take a $1 eBay LED DC voltmeter and add 50 cents or so of parts, you can make a self-powered AC voltmeter with (in my opinion) acceptable accuracy over a practical range of O-gauge track voltage, say, 10-20 V AC.
Note that for another 25 cents or so you can get a panel mount version of the DC LED voltmeter.
Here it is in action measuring the Z-4000 AC output as the handle is moved up and down between 10 and 20 Volts AC.
The idea is to convert the AC to DC with a bridge rectifier and capacitor. The DC powers the $1 LED voltmeter module. A 10k trimmer potentiometer divides the DC voltage to scale it to the magnitude of the AC voltage. The potentiometer is adjusted to minimize error at the center of the measurement range...in this case 15V AC. The MacGyver AC meter will under-report voltages at the bottom of the range, and over-report at the top of the range. But as the video shows, it's really not that bad..maybe 1V error at the end points.
Note that most, if not all, AC digital voltmeters have at their core a DC voltmeter! I recall a recent OGR thread where the application of the digital panel meter was to monitor the AC accessory voltage (14V AC). So in that application, this self-powered $2 digital meter would be "centered" at 14V and would be suitable for monitoring/verifying the accessory voltage.
Anyone who has made it this far in reading this should be able to imagine how a $1 current-transformer off eBay can extend this technique to an AC current panel meter with similar considerations.
This is simply a take-it or leave-it idea that only took a few minutes to dream up and prototype.
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Recovered posted:
Anyone have have any thoughts on this volt amp meter for use on a postwar ZW
Thanks every one for all the input, Now I'm thinking maybe just buy a couple cheap multi meters and wire them in to my 2 ZW outputs and use my regular clamp amp probe to check amp draw.
This is simpler for an AC voltmeter:
http://www.ebay.com/itm/85L1-V...b:g:sowAAOSw5cNYTMiq
Sometimes it's better to aim for mid scale for your normal reading:
http://www.ebay.com/itm/AC-30V...2:g:VakAAOSwRgJXhvwg
Here's a simple AC ammeter:
http://www.ebay.com/itm/Class-...0:g:tuoAAOSweXhXmOCA
Look around in this ebay area for analog meters, there are many, and for our purposes accurate enough if they are repeatable. Stan2004's idea is of similar or better accuracy actually.
gunrunnerjohn posted:Chuck, I insisted. I asked for a return shipping label since they were not as advertised, and of course a full refund. Knowing they probably had about 50 cents into them, they decided to issue the refund and skip the return shipping. I can only imagine what it costs to ship something to China, but I know it's not cheap! Shipping the other way is a whole different story...
Same exact thing happened to me. I am lucky I checked the meter label, because the box was labeled different. I had four meters. They made me pay return shipping to China, but reimbursed me for it. I was shocked that it was only about $15 shipping.
Yes if I had looked at the meter face in the original ebay ad, I would have seen the dc symbol right on the meter. Of course, sometimes the pictures are generic, but this time not. Anyway, I made use of them and would have ordered them for a future project for my sign power supplies.
I bought this
http://www.ebay.com/itm/1pcs-A...?hash=item51ef6f5949
and this
http://www.ebay.com/itm/3-1-2-...?hash=item1e7a6ee515
and something like these
http://www.ebay.com/itm/DC-DC-...?hash=item232c131329
I bought 4 of each to handle 4 train power feeds. The isolated converters are critical. I powered the converters with a laptop power supply. I added a power jack and switch to a Radio Shack breadboard to wire everything. This was a fair amount of soldering for me. The meters are mounted to a black chalkboard panel from Home Depot. I suggest making a cardboard template first.
All in, it cost a little over $90 for the project and took time ordering, waiting for and wiring the parts; probably about 3 months start to finish.
Sorry, I forgot to take pictures today. I would have bought the Lionel unit and mounted it to my panel if it was available.
George
Recovered posted:Thanks every one for all the input, Now I'm thinking maybe just buy a couple cheap multi meters and wire them in to my 2 ZW outputs and use my regular clamp amp probe to check amp draw.
Careful, I looked at Harbor Freight, and the cheaper model didn't read AC volts. Also, you will need to set the meter to measure current or volts, one at a time, and the LCD display is hard to read in low light.
cjack posted:I wonder if this meter
http://www.ebay.com/itm/Blue-D...%26sd%3D400888428064
which has the separate power supply (4 wire hookup), actually reads down to 0 Volts AC
I bought ones like those first. They work but do not display tenths of a volt.
For the Postwar ZW, the 20 VAC meters I linked above should work, but I heard the Postwar ZW can put out up to 21 volts. I use mine with PH 180 power supplies that put out 18 volts.
stan2004 posted:... SNIP ...
Anyone who has made it this far in reading this should be able to imagine how a $1 current-transformer off eBay can extend this technique to an AC current panel meter with similar considerations.
This is simply a take-it or leave-it idea that only took a few minutes to dream up and prototype.
Stan, I tried this exact technique when I first did my track voltage measuring car. I wasn't able to get a calibration close enough to make it workable, I had at least 2 volts error in spite of adjusting the range.
I wonder if it would be possible to tinker with a component value in the A/C meters to get the voltage range down into the useful range for O-gauge work?
gunrunnerjohn posted:stan2004 posted:... SNIP ...
Anyone who has made it this far in reading this should be able to imagine how a $1 current-transformer off eBay can extend this technique to an AC current panel meter with similar considerations.
This is simply a take-it or leave-it idea that only took a few minutes to dream up and prototype.
Stan, I tried this exact technique when I first did my track voltage measuring car. I wasn't able to get a calibration close enough to make it workable, I had at least 2 volts error in spite of adjusting the range.
...
Well, you must first watch a few re-runs of MacGyver to focus the mind!
With AC track voltage of 15V, the 10k trimpot sets the LED digital output between 0 and 19V...which is what I would expect. That is, 1.4x multiplier going from AC-to-DC into a capacitor...less 1.4V DC thru the bridge rectifier.
In any event, this was inspired by comments on other OGR threads about how guys actually use an LED panel voltmeter in modern layouts. That is, you have a KW, ZW, whatever with variable output...and you want to set it to fixed 14V AC for Accessory Voltage. Or set it to fixed 18V AC for command track voltage. In other words, the required operating window is somewhat narrow. So as long as the meter does not indicate something stupid outside of that range...
As you know, when troubleshooting vexing voltage issues on a layout, it's rarely an issue solved by looking at the transformer's digital readout. That's where your Voltmeter car saves the day because the problem is undoubtedly something in the wiring, connectors, etc. after the transformer. In my opinion of course!
I used the analog meters like cjack linked above. I have 0-30 vac and 0-15 amp. Then I copied GRJ's voltage car (with his help) when I saw the digital combo meters, been looking ever since with no luck so far. The analog meters work fine and require no external power, just connect to the power wires to the track. I like Stan's idea too, actually I like all of his ideas like this!
Stan, I agree that it would likely be sufficient for must uses. I just wanted the voltage to read fairly close to actual, it's my OCD side.
In case anyone reads this page, I found some digital Volt and amp gauges on Amazon. they are powered by AC or DC 8-12V and will read 0-10AAC and 0-600VAC.
Good finds! Thanks for the links, from looking at them I also found this one:
Yeeco AC 0-199.9V LCD Display Digital Voltmeter Voltage Meter Volt Testing Gauge Voltage Measuing Volt Panel Meter also from Amazon. Looks like it has a little better resolution (in tenths) and smaller/tighter range which might provide a bit more accuracy.
Unfortunately they are priced much higher than the ones that were available a few years ago, but those seem to be extinct these days. However, since I am a sucker for these things, I might just try a couple to see how they work out.
As you say, the 600V one doesn't have enough resolution. I wonder about the absolute accuracy of the 199.9V one as well...
Accuracy: 0.5% ± 2 words
Words? What does that mean? Usually, it's ± so many least significant digits for digital meters.
I like the 10A meter, that's a good find except for the price...
The listing suffers from a translation. Words must mean least significant digits. I especially like "(Separately power supply, otherwise the instrument to burn)" on the ammeter listing.
I missed the 'Accuracy: 0.5% ± 2 words' part... I have no idea what that means either? A Typo, and they really meant what you said about the digits?
I am guessing they might be close enough though, I think my copy of your voltage car has the 0-199.9V meters in it and it has always been fairly accurate. Sure wish they would bring back the less expensive models and make a combo volt/amp meter that we could use for trains.
I'd love to find more of the 0-20V meters I got for my voltmeter car, they were perfect, but I don't see them anymore.
I may have gotten the last two of those 0-20V meters? Those were the ones that burnt up rather quickly when I powered them up...no DC-DC converter that you later told me about, oops! When I went back to order replacements, all they had was the 0-199.9V ones and I don't recall ever seeing the 0-20v again after that. At least they still had AC meters back then and they were only about $4 or so as I recall.
Recovered posted:
Anyone have have any thoughts on this volt amp meter for use on a postwar ZW
Recovered posted:
Anyone have have any thoughts on this volt amp meter for use on a postwar ZW
