Amp gauge appears not to work

Tom Jubilee · Mar 29, 2010

Help again! Cannot get amp gauge to work (it does work when I take it off tractor and hook a hook a light and battery to it). The pic shows the way I am wired up. What am I missing? I would think with lights on and/or rolling tracor over I would get some movement of needle...but no.

JMOR · Mar 29, 2010

(quoted from post at 21:03:48 03/29/10) Help again! Cannot get amp gauge to work (it does work when I take it off tractor and hook a hook a light and battery to it). The pic shows the way I am wired up. What am I missing? I would think with lights on and/or rolling tracor over I would get some movement of needle...but no.

I see nothing wrong with the drawing wire connections.

Dell (WA) · Mar 29, 2010

Tom.......I don't see 'nuttin' wrong in yer diagram. Howsomevers, meters can be "position sensitive", work ok vertically, but not horizontally. Understand the concept? Which may explain working off the tractor on the workbench OK. Each headlite otta be worth about 4-amps, ignition coil worth about 3-amps; total draw 11-amps without the alternator charging and should be quite noticeable iff'n meter is enny good. I'd disconnect the alternator output from yer terminal board and try yer headlites ON/OFF to see a wiggle, ignition OFF.

Remember yer dashboard amp-meter is only 20% accurate. So instead of indicated 11-amps, could indicate 8-amps or 14-amps. (charge or discharge, mox nix) .......Dell, retired calibration lab Engr

Anonymous-0 · Mar 30, 2010

Why not swap your amp meter for a volt meter?

JMOR · Mar 30, 2010

(quoted from post at 01:03:49 03/30/10) Why not swap your amp meter for a volt meter?

hat is it called when a question is answered with a question?

Peter, Covington, LA · Mar 30, 2010

This is one of those "don't ask how I know" answers:

It sounds like your ammeter's mounting strap is causing a short circuit across the two terminals of the meter, so the juice is flowing through the strap rather than the meter.

The danger here is that the strap is also grounded to the instrument panel unless there is sufficient paint to insulate it. A real "short" here will be a wire-burner.

Tom Jubilee · Mar 30, 2010

OK all. Got it to move while on tractor. Will not move turning over engine. Wired up 3 lights and it does draw down a little. Dell maybe correct. Not very accurate piece of .... equipment.

Thanks once again y'all

JMOR · Mar 30, 2010

(quoted from post at 19:09:42 03/30/10) OK all. Got it to move while on tractor. Will not move turning over engine. Wired up 3 lights and it does draw down a little. Dell maybe correct. Not very accurate piece of .... equipment.

Thanks once again y'all

on't forget that while "cranking over the engine", the ammeter is seeing barely over one amp & the full scale is probably 30 amps, so 1 of 30 is just a wiggle. Yes, I know everyone is accustomed to the 3 or 4 amps 'coil current' numbers, but that is stalled/points closed, not making & breaking involving duty cycle (dwell) & exponential charging current of coil.

Tom Jubilee · Mar 30, 2010

JMOR... That's it. That appears to be my problem (besides my lack of knowledge).
Thanks again
PS. I will be back with more questions I am sure

Amp gauge appears not to work

Tom Jubilee

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JMOR

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Dell (WA)

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Anonymous-0

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JMOR

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Peter, Covington, LA

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Tom Jubilee

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JMOR

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Tom Jubilee

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