The Ford Barn

Kevin in NJ · 08-23-2022, 06:56 AM

The ammeter has an area of trouble.

The 2 studs are drawen down tight to the bus bar on the inside of the meter. All the current flows along this bar to make the magnetic field to deflect the needle.

The trouble comes with a problem between the studs and the bus bar. On original ammeters this is mostly from corrosion if moisture gets in, but they tend to be ok because the copper is a better quality.

The reproductions use a lower grade of brass for the bus bar. They tend to get corrosion which increases resistance and creates heat.

The fix is kind of simple, but needs careful soldering skills. You need to lightly tin and the bus bar and stud. Then sweat them together. The difficulty is keeping the stud close to the bus bar, you need it touching.

While my original meter had good connections, I still soldered them. In the end this will slightly reduce resistance which can only help the system.

I will note that I am very skilled in electronics soldering and very picky how I do things. I would recommend that you practice soldering some before tackling the real meter you intend to use.

08-23-2022, 06:56 AM	#21
Kevin in NJ Senior Member Join Date: May 2010 Location: South East NJ Posts: 3,398	Re: Can ammeter cause trouble? The ammeter has an area of trouble. The 2 studs are drawen down tight to the bus bar on the inside of the meter. All the current flows along this bar to make the magnetic field to deflect the needle. The trouble comes with a problem between the studs and the bus bar. On original ammeters this is mostly from corrosion if moisture gets in, but they tend to be ok because the copper is a better quality. The reproductions use a lower grade of brass for the bus bar. They tend to get corrosion which increases resistance and creates heat. The fix is kind of simple, but needs careful soldering skills. You need to lightly tin and the bus bar and stud. Then sweat them together. The difficulty is keeping the stud close to the bus bar, you need it touching. While my original meter had good connections, I still soldered them. In the end this will slightly reduce resistance which can only help the system. I will note that I am very skilled in electronics soldering and very picky how I do things. I would recommend that you practice soldering some before tackling the real meter you intend to use.