ac amp meter

It's small, it's analog, and it may never read more than 5 amps ever. I'd go with a digital version.

How about these, as a bonus they are the same style for the amps and volts.

0-10A AC ammeter, $4.28, free shipping, on eBay: 171747351449

0-30V AC voltmeter, $4.28, free shipping, eBay: 181266866831

There was a long thread on this awhile ago

https://ogrforum.ogaugerr.com/...20#72101420663193820

Brendan

consolidated leo ,Why do think it would never read more than 5 amps ?, it is rated 0-25 amps .  Just wondering .

Look at the scale... most of the running will be under 5 amps, that meter would be nearly useless in the range needed for our use.

This one would be better, but still not ideal(and still pretty small at  2.375" square):

Leo,i see what you mean ,thanks for pointing that out .

  John ,Your meters are the way to go & they are cheaper ,as i said i already ordered one volt meter from a different vender ,so i will order the rest of the meters from your suggestion ,it will just take longer to get ,there isn't any big rush on my part . Thanks for all your help.

I have some just about like GRJ posted above. They work just fine, had them for 3 years or so. Mine may be slightly different ranges, but have the same MUA or whatever it says in the lower left corner. Others are correct about the ranges, smaller range, more accurate reading. Rule of thumb used to be operating point should be mid range of meter or gauge scale. So the 0-10A meter for a 5A operating current would be just right. 

I would also gladly switch to digital meters, if I could find any for AC at a reasonable price as the ones above. They had them all over ebay a few years ago, but they have now disappeared. I haven't looked recently, but they do seem to be quite rare these days. If anyone finds any please post a link or start a new thread about them. I am still interested.

Gerald, I use these (link below) on each loop of my Outdoor G Scale layout (DC).  One for Amps, one for volts.    They have these in AC as well.  I like them because they are Zero Center, they read positive with throttle in forward and negative in reverse.  Most models do not require shunts.

I love 'em.

Chris Sheldon

gunrunnerjohn posted:

0-10A AC ammeter, $4.28, free shipping, on eBay: 171747351449

0-30V AC voltmeter, $4.28, free shipping, eBay: 181266866831

I'm ordering some of these. I use the ZW digital meter for the Christmas layout and it's very impressive, but the shortcomings when used on a common ground layout(current readings are combined and divided evenly in the amps display) are tough to ignore. I figured out how to use the 4 displays for 4 discrete transformers but as soon as any of the power districts share a common return the current readings don't mean much. It seems Lionel really goofed when they put the ammeter sensors in the common/"U" posts.

I'll have to admit Rob, I never did understand why Lionel thought that amps on the common made sense.  I think it was probably because it was a lot easier circuit-wise.  To measure it properly on each output line would have required isolation of each amp measurement circuit, that probably stopped them in their tracks.

John ,just put my order in ,now the wait to get them ,i hope i don't have any trouble hooking the meters up ,it will be a learning experience for me & a lot of fun .

gunrunnerjohn posted:

...To measure it properly on each output line would have required isolation of each amp measurement circuit, that probably stopped them in their tracks.

They are isolated on each individual circuit, but on the "U" posts! Very confusing.

Is it possible to isolate a circuit so the amp meter makes sense if the entire layout shares a common ground?

ADCX Rob posted:

gunrunnerjohn posted:

...To measure it properly on each output line would have required isolation of each amp measurement circuit, that probably stopped them in their tracks.

They are isolated on each individual circuit, but on the "U" posts! Very confusing.

Rob, making the voltmeters work for each channel was easy, as they share a common ground.  However, to measure the current for each channel, there is no common ground readily available that all measurement channels could share.  In order to measure current for the individual channels, each measurement channel would have to have it's common electrically isolated from the other channels.  That's not super hard, but I suspect when this circuit was designed, it was harder and more expensive.

The way to do the current would have obviously been a doughnut around each power feed wire, then you could have simpler circuitry for the meters.

MrMoe50 posted:

Is it possible to isolate a circuit so the amp meter makes sense if the entire layout shares a common ground?

Sure, you measure each power feed with a current sensing toroid core around each power feed.

Gerald, just remember the ammeter goes in series on your hot line and the voltmeter is connected to hot and ground.

John H,  Thanks for the information ,i don't think i will have much of a problem ,but if i do i will come back to the best place ,right here on the forum where there are many people such as yourself & many others with a lot of knowledge about these things ,i enjoy doing these things more than running trains ,because of my limited knowledge it is always a challenge ,but i enjoy doing it & i learn things during the process ,which makes me feel good ,when i get the meters installed i will post pictures of my progress .

I have 4 round analog amp meters where the hot line goes through a seperate inductive pick up coil eliminating the need for a common.(I think) I have not installed them yet.Nick

Be aware if you have a short, the analog ammeter needle, depending on its range, can slam against the stop bending the pointer.  You could put a fuse in line but the needle will bend quicker than the fuse element blows (not sure how fast electronic breakers works compared to how fast meter needle respond).  A digital meter will just max out or display "Err" with usually no ill effects.

Probably want a analog meter approximately double whatever your power supply can put out into a dead short.  Of course, the meter readings then may be on low end of scale making it difficult to resolve how much current a consist is pulling.  But if all you want is to check there is/isn't current then range would be a non-issue.

RRMAN, I 'm not worried about the needle bending if there were a short ,as the meters are cheap enough & easy enough to replace i didn't even think about that happening ,as i said before i just want to get an idea of what the readings are at any given time ,but most of all it is just something for me to do & i like the looks of the meters on the layout & i enjoy these simple wireing projects .