How to buy/connect amp meters

Dave2

Sounds like your are wired correctly. Do you have a load [ as in engine,train,etc,] on the rails that is consuming amperage. If not zero amps is the appropriate reading. Fire up an engine with some lighted passenger cars or lighted caboose and then check the Ammeter for that power district

Amp Meters shown are in the lower row--wired inline, in series. 3 separate power districts--Green, Red, Black.

Yes, Dewey, I had a train running.  The ammeter is a 0-20 amp so I would expect at least some movement, a 2-3 amp reading at full speed.  Looking at the back of your pics, I believe your ammeters are on top and your voltmeters on the bottom?

oops.  Guess I didn't read the bottom sentence of your reply.... Sorry.

Still obsorbing the picture.  I see why you say the ammeters are on the bottom now. 

Wrong Dave--study the photo.

Ammeters are on the bottom row wired inline, Hot only, or in series.. Examine the top row: a "Hot" jumper [Green, Red & Black]from the Amp Meter post up to the Voltmeter to one side of the Voltmeter and a Common Return [white] directly from the "U" of the transformer to the other post. This illustrates the "across the line", HOt & Common, or parallel wireing of the Voltmeters.

Your Amp Meters should be wired with the same heavy wire that you use for railpower since all the load flows through them. The Voltmeters can us e smaller wire since they are merely monitoring "across the line".

Just read your post--you have it now.

I hope you find a answer . Have the same problem. Dewey I think I copied your pictures from a previous post???? and installed mine the same way. I thought maybe 20 amp meter was to much to make it give me a reading?>???

Larry

Unless you have PoHos in parallel for excess of 10 amps per power district[per oval, loop, block,per throttle,etc]a 0-15 amp range Amp Meter is sufficient for Toy Train useage on 10 amp districts. If you are running over 10 amps in your district you are in rail "welding" territory upon a derrail short. Been there several times and experimented with that.

Check the inexpensive Voltage and 0-15 AAC Amperage Meters on "Light Object"--about $10 each for analog. Shurite and Simpson also have similar meters but more expensive.

If you know that you wiil be operating at less than 10 amps with say, 7.5amp[135 watt] PoHos "Bricks' or similar, you can get 0-10 amp range Meters at ALLElectronics, Inc.

Thanks Dewey. I got in a hurry and couldn't find the 10Amp and picked up the 20. I'll get the correct ones with the new layout I'm working on.

Dave2, some of the instrumenation where I work uses ammeters for various loads but actually uses voltmeters for display.  What I see done sometimes is the use of a 1 ohm resistor in line with circuit of concern.  The a voltmeter will measure the voltage drop across the resistor and "display" that in amps (when it is really a voltage drop).  Any chance your new ammeters are suppose to be configured that way?  The other way it can work is a current transformer (CT) on the circuit to sense and measure current.

Tx for the reply Steims.  What I know about CT's is that they are expensive creatures and seem overkill.  Are you of the belief that this ammeter pictured above is a voltmeter and not a ammeter even though it's faceplate indicates it as an ammeter?   My question is why don't I see any reading at all and why don't the train run when it's wired in series?  Is the lack of an internal shunt the cause?  Normally wouldn't a ammeter advertised as a "AC" ammeter have an internal shunt (resistor)?  What good is it otherwise?  I work with 110/220 and my amp probe reads amps.  It's a CT.  I've worked with DC ammeters with no problems.  But this AC thing has me puzzled because I'm not an electrical engineer.  If it's a ac voltmeter like you said, my understanding is that the ac waveform will effectively cause it to read 0.  But I would have thought that current would still flow through it allowing the train to run.  Is my logic correct here?  Tx for your help and thoughts. 

Thanks for the repl Dewey.  Don't be sorry.  I understand what it means now.  Tx.  Being somewhat recently retired I've taken up this hobby and I'm getting smarter thanks to the brain trust on this forum.  I would have never guessed that pitting would occur with "toy" trains as a result of being dragged over the tracks.  I've just started to notice sparking as they go over switches.  Also that the track "hums/cracks" at joints if they're not tight.  I'm learning.

Yes, these were $5 meters from Hong Kong as I recall.  And OMG.  It just hit me what you wrote.  Hot to center.  I've been hooking them hot to common.  No wonder it don't work.  Nothing is going through it and I've effectively unhooked the track.  Duh!!!!   Let me go see if that's the problem.  As Swartsnegger said, "I'll be Back".    

Dewey.  It wasn't the wiring.  I had it wired right.  But I found the problem.  You get what you pay for.  I can't believe that not one but both of the gauges had some of the plastic flashing from manufacturing, partially covering one of the terminals on both of the gauges.  As my eyes get older, they don't see as good without good light.  I by accident hooked the wire clamp furthur out on the gauge screw where it was able to make contact.  Viola! It works.  Restored my faith in electricity one more time.  I also will be taking a razor blade to the flashing.  And Larry, for sure you'll need to buy some 10 amp ones too, for easier readability.  I expected two trains on the same track with 6 lit cars to draw a lot more than three amps full throttle.  Tx for the help and feedback everyone. 

Good News on the meter connections. Being on the verge of 81 years,I can empathize with eyesight, hearing and peeing problems.

Dewey I can sympathize with you. I'm only 66 and I have all those problems also.

Ron

Dave2 & Larry Sr.

Showing a couple of brands of 0-15 amp AC panel meters side by side:

On the left a Light Object brand YS-670, Order #EPM AAC15A----$9.50 each.

On the right a Shurite brand #8206Z 15 AAC-----$18.70 each.

I have not done any long term testing or useage of either brand. I bought them when I retreated to a small attic layout with only two power districts and running very short trains. On my two large layouts dismantled at the mountain cottage in '08 and here in the Condo in Oct '09, I used higher range DER Meters assembled in Taiwan from Japanese components.

The Shurite Meters are higher quality construction and note a 1-1//2 to 2% possible variation range while the Light Object units are 2-1/2%. Shurite are also twice the cost if that is an issue. Shurite are assembled in the Dominican Republic of USA components. I ordered mine from Allied Electronics. They also have a VAC 25 volt unit #8412Z which I have....about $22.

The Light Object Meters have Asian lettering/symbols but I am unsure of the exact production location. Light Object also has a VAC 0-30 Voltmeter, RIAND EPM @ $9.50. On a short term basis mine have worked just fine so, if interested in buying Meters, I see no reason not to try them at the price.

Well this has been a very interesting conversation to me. I appreciate the information from all of you electrical guys. My electrical knowledge is not that bad when it comes to house wiring but the train knowledge has mostly come from helpful members. Starting a new lay out 16X28  introducing TMCC and Legacy and maybe DCS I am a ways off for the new panel but you can be assured I come back to these post. My meters are all boxed up currently but I remember Dewey getting the ones that you have talked about before. They were not 5.00 meters. I know my 1st mistake was I never even put a load on them. duh

Thanks again guys.

Larry

Your plans sound exciting Larry. 16x28 is a good sized layout and operating with Command systems will provide a lot of flexibility of operation and equipment use.

Happy Railroading!

Well it sure will be fun in my older age. As a one man show it will take some time. I just got all the conventional stuff boxed up and getting ready to tear up most of the previous bench work. I been buying stuff for this project for a year or so. Might as well get started. Maybe before I'm dead..hee hee.

Sorry Dave2 I didn't mean to steal your thread here.

Larry