In Reply to: ammeter posted by chris eby on April 29, 2018 at 18:58:14:
The FORD TRACTOR Ammeter, first released as part number 9N-10850, was a -20/+20 scaled amp meter used on the first 4000 units. It had four screw terminal posts, two of which were wire terminals, two others were for the mounting bracket. At or around s/n 9N-4000, Ford made it obsolete ad released the new -30/+30 Induction Ammeter, part number 9N-10850-B often called the ‘loop’ style because it comprised a steel loop on the rear panel which now the wire was not cut and sliced but simply passed thru the loop and by means of electrical induction, would power the meter. The Ford basic part number for ammeters is 10850, meaning a Model A, or early V8, or 9N Tractor all carried it. It is the part prefix which designates the type and would be the first module the unit was used on. Thus, a ‘9N’ prefix means the specific device was first used on the 9N tractor. When a part has a suffix letter it means there was engineering change that defined the part as being revamped. Sometimes you will see a suffix like “A-1” which denotes that there are two or more suppliers of the same part. Might be TMI…but hope it answers your inquiry.
FORD TRACTOR ORIGINAL 9N-10850-A 20/20 AMMETER:
FORD TRACTOR ORIGINAL 9N-10850-B 30/30 LOOP/INDUCTION AMMETER & AFTERMARKET STYLE:
EARLY 8N CORRECT DASH WIRING w/LOOP/INDUCTION AMMETER UPPER RIGHT: