Moving coil ammeter.

[petercharlesfagg]

I have been following the post by another member about overheating loco's and the use of a moving coil ammeter to check on voltage fluctuations to forewarn of problems.

Would this one be of any use or is one that is mounted directly to the outgoing cables to track better?

http://www.ebay.co.uk/itm/Sealey-SPECIAL-Clip-On-Ammeter-0-30-Amp-any-direction-/160642037666?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item256702f7a2

What would others recommend?

Regards, Peter.

[keithfre]

Would this one be of any use or is one that is mounted directly to the outgoing cables to track better?

You'd certainly need one that's more sensitive. You're only trying to read values up to about 2A.

[keithfre]

Perhaps something like this:
http://www.ebay.co.uk/itm/85L1-A-AC-0-2A-Rectangle-Analog-Panel-Ammeter-Gauge-/190837351611?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item2c6ecae4bb

[Dorsetmike]

On a DC layout locos like Poole Farish designs, Fleischmann and other older models draw a maximum of about 300 miliamps = 0.3 amps, at lower speeds often as low as 100mA (0.1A)  most modern ones  less than that so a meter with a maximum reading of 1 amp, would cope with a triple header.

I have no experience of DCC requirements but as a number of locos could be running at the same time then you may need more than 1 amp if  you have a really large layout running half a  dozen locos. Is there any built in overload detction in a DCC chip in a loco? If not how do you detect an overload fault and know which loco is causing it?

On DC it makes much more sense to have an overload cut out that can detect just a little above your likely maximum current, or even have it adjustable to suit the loco(s) being run.

[petercharlesfagg]

Perhaps something like this:
http://www.ebay.co.uk/itm/85L1-A-AC-0-2A-Rectangle-Analog-Panel-Ammeter-Gauge-/190837351611?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item2c6ecae4bb

Thankyou for the suggestion.  Is it an easy job for a lay person to add to the outputs of a DC controller?

Regards, Peter.

[guest311]

I have been following the post by another member about overheating loco's and the use of a moving coil ammeter to check on voltage fluctuations to forewarn of problems.

Would this one be of any use or is one that is mounted directly to the outgoing cables to track better?

http://www.ebay.co.uk/itm/Sealey-SPECIAL-Clip-On-Ammeter-0-30-Amp-any-direction-/160642037666?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item256702f7a2

What would others recommend?

Regards, Peter.

can't open the link due to the filters at work, but it sounds from the description very much like the ones we used to have when I was on the AA for checking battery charging.
just clipped onto the positive lead and it would show what the battery was drawing from the alternator.

obviously as per another reply far too insensitive for our requirments

[Luke Piewalker]

I will say this, if you are going to mount it in a box, with 4mm banana plug sockets to connect it inline, make sure you haven't accidentally bought an AC one...

If only it had a wavey line smack in the middle of the gauge to act as a subtle hint... 

Unfortunately my multimeters only have a choice of 200mA or 10A range, and as I found out, it's quite easy to blow the fuse on the 200mA input.

I did end up having to buy the gauges from Hong Kong on the ebay.

[Dorsetmike]

Main problem you will find when installing is that when a loco is going forward the meter will read, but when you reverse the loco direction, the current flows in the opposite direction and the meter will attempt to read negative. There are such things as "Centre Zero" meters in which as the name suggests the needle is initially vertical = 0 current, send the loco in one direction needle moves right, in the other direction needle moves left.

I've spent the last hour or so googling  for such a beast at a sensible price from a UK dealer, one would think they had ceased to exist except for laboratory Galvanometers at upward of £50, or else something measuring 50-0-50 micro amps or at the other extreme 50-0-50 amps.

[Luke Piewalker]

That's why I went with the banana plug arrangement, I connect my controllers to the layout with banana plugs so I can easily plug the ammeter in and out as required.

[Dorsetmike]

I did finally find a centre zero oneon Ebay, but the lowest current one was 5-0-5 amp which is still a bit more than needed and listed as B-I-N for £14.99.

Luke's idea sounds about the best, especially if you have more than one controller and you can remember which socket is positive and which negative for either loco direction. you will also need a length of wire with banana plugs both ends for when the meter is unplugged.

[AndyGif]

http://www.ngaugeforum.co.uk/SMFN/index.php?topic=12276.msg126035#msg126035

Trials and tribulations of doing a similar thing.

[petercharlesfagg]

http://www.ngaugeforum.co.uk/SMFN/index.php?topic=12276.msg126035#msg126035

Trials and tribulations of doing a similar thing.

Many thanks for the comments and recommendations, I am so confused now I wish I'd never asked!

I shall just run the things and hope for the best, I no longer understand all the jargon!

Warmest regards, Peter.