Bench Test Ammeter Gauge

[6pk2goDemon]

Is it possible to bench test an ammeter gauge? Pulled the dash cluster on my 72 to changeover the plastic face and while there I'm wondering if there's a way to test it....

Thanks in advance for any help!!

Disclaimer....I hate electrical & consider it quite the challenge LOL :banghead:

 

[RedFish]

The tiny post that the needle mounts on is harderly even swedged into the brass shunt. So how to test is it about to fall out ? I give up. No big deal though. When it does fall it just turns the needle into a cig' lighter for a moment. LOL
The stator is magnetic and I often find debris collected there. I'll clean a amp gauge with compressed air, repaint its needle, etc.., for free, while servicing a inst' panel but that's all.
As for testing, qualifying, or taking any responsibility for that instrument... Not me.
I cant afford to.

 

[67Dart273]

Sure, you just need some sort of load, and the very easiest way to check would be with a multimeter that has at LEAST a 20A scale, and preferable a 30 or more amp scale.

Coming up with a load, though, might be the tough part. You have a battery charger that can output 20--30A? That would be one way.................. pick one of your cars on which you can access the battery.

Leave the lights on for say, a 1/2 hour with the engine stopped.

Then hook up your battery charger with your multimeter and the car ammeter in series. to charge the battery, and check the car ammeter against your multimeter.

You'll need to take some nuts and make sure the ammeter terminals are firmly tight

I don't remember the scale anymore, seems to me the last mark is 40A

Calibration is not all that important, as long as the needle is free and "repeatable," and stays centered with no current.

Really not much to go wrong, other than bad connections to the shunt inside.

 

[BillGrissom]

As mentioned, you need a way to measure actual current. 273's idea of using a discharged battery as the load is clever. I have an old dial ammeter w/ 100A range that I clipped in series with the alternator output wire for testing. However, that is a PIA. Recently, I got an F.W. Bell clamp-on DC probe for only $15 off ebay. That is the same model we bought for $350 at my prior company for a test system.

I still remember locating the big connector on my 82 Aries to tap into the alternator current with my in-line meter. Eventually, I found an easier way to tell when the square-back alternator (same as Darts) died again. Just look thru the holes and see if the floating diodes had vaporized (every 2 years, probably from poor cooling in the transverse engine).

 

[inkjunkie]

Interesting.....

 

[67Dart273]

Bill what is the model/ maker of that clamp on toy?

 

[BillGrissom]

F.W. Bell is the original manufacturer of the "current gun", maybe ca. 1990's. They were also sold under the Fluke name. I don't know that they are sold new anymore. The main maker today is AEMC, also sold as Fluke. Many models (ex. SL261). However, those might be hard to find cheap. F.W. Bell's are found when cleaning out government labs. People buy the pallets at action and relist parts on ebay.