Not strictly Picaxe but it is electrical

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donrecardo

Senior Member
I know its a daft question , but I just dont know the answer

I could find it out by connecting it up and measuring but I hoped a quick yes or no answer from one of you would save me the effort.

I have built a large (5" gauge) model train . Its battery powered through 4 large motors and runs off 24v.

I have my two 12v batteries in series to give the 24v required and now I want to fit a digital ammeter which I already have so I can know how much current the motors are drawing.
The simple answer would be stick the meter shunt in the main battery positive or negative lead , but there is not a lot of space to fit it in there , however there is room to fit it in the lead that joins the two batteries together .
I have made a picture to show what I mean , lets see if I can find out how to attach a picture ......
http://donrecardo.pwp.blueyonder.co.uk/3.jpg

I am assumming that no matter if I fit the ammeter in the red, black or green lead the current will read the same as I assume its the same all around that part of the circuit but could someone please confirm if I am right or not please

Regards
Don
 
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Rickharris

Senior Member
donrecardo said:
I know its a daft question , but I just dont know the answer

I could find it out by connecting it up and measuring but I hoped a quick yes or no answer from one of you would save me the effort.

I have built a large (5" gauge) model train . Its battery powered through 4 large motors and runs off 24v.

I have my two 12v batteries in series to give the 24v required and now I want to fit a digital ammeter which I already have so I can know how much current the motors are drawing.
The simple answer would be stick the meter shunt in the main battery positive or negative lead , but there is not a lot of space to fit it in there , however there is room to fit it in the lead that joins the two batteries together .
I have made a picture to show what I mean , lets see if I can find out how to attach a picture ......
http://donrecardo.pwp.blueyonder.co.uk/3.jpg

I am assumming that no matter if I fit the ammeter in the red, black or green lead the current will read the same as I assume its the same all around that part of the circuit but could someone please confirm if I am right or not please

Regards
Don
Click to expand...
Kirchov's law says - more or less - that the same current flows in all parts of the circuit. Assuming no parralell paths then no matter where you red the current it will = the total current.
 
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Andrew Cowan

Senior Member
Yup - you can fit it anywhere.

I like fitting fuses between batteries - it means that if there is a short with the fuse not in the circuit, only one battery will be involved.

A
 
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manie

Senior Member
Google for the LEM HAIS 50-400 amp Hall Effect sensor. I've used it extensively and it works very well. Very accurate, down to low amps (5A), at your current levels it will have no problem....
Manie
 
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