Hooking up ammeter on 1951 Ford 8N.

[Philco]

On my 1951 8N 12 volt conversion tractor, negitive ground system, I installed a new ammeter purchased from a Ford tractor dealership. The needle doesn't move from zero and just flutters there.. This is how I hooked it up. hooked up The single wire from the alternator connects directly to the negitive side of the ammter. The other wire coming from the solonoid from where the battery cable connects, is attached to the positive side of the ammeter, BAT+. The ignition key yellow wire is attached to the ammeter positive side along with the solenoid positive wire. And of course, the black wire from the off/on switch is attached to a junction block along with the white wire going to the coil positive side. I know this is hooked up correctly, BUT why doesn't the ammeter register more than just pointng to the 0 (zer0) on the ammeter. Question 2>> Is a voltmeter a more informative gauge now that the tractor is a 12 volt negitive ground systerm? I just want to be confident the alternator is charging the battery as I go along mowing the grass, or plowing the snow. Thanks greatly!

 

[stdsch40]

I'm not an expert on Ford 8N tractors but do know wiring. First off the single wire from the alternator would be a POSITIVE if as you say the tractor is NEGATIVE ground. Suggest you verify the single wire is in fact POSITIVE, and if so connect it to the +ve of the ammeter. Hope that you understand that ammeters are POLARITY sensitive. Start there. A voltmeter is also POLARITY sensitive, if you decide to change the ammeter for a voltmeter.

 

[Mad Farmer]

I'm not an expert on Ford 8N tractors but do know wiring. First off the single wire from the alternator would be a POSITIVE if as you say the tractor is NEGATIVE ground. Suggest you verify the single wire is in fact POSITIVE, and if so connect it to the +ve of the ammeter. Hope that you understand that ammeters are POLARITY sensitive. Start there. A voltmeter is also POLARITY sensitive, if you decide to change the ammeter for a voltmeter.

Backwards it will just show discharge charging and charging discharge, but still should move.

Check continuity from alternator to selenoid .

Be sure it's a 1-wire alternator, 3-wire requires an exciter wire.

 

[Jim L WA]

If the battery is fully charged, you won't see much fluctuation while running. that would be normal. If your tractor has head lights or a work light, turn them or it on and you should see a negative movement on the ammeter. If you don't have any lights you should see some movement just turning the ignition on.

 

[used red MN]

The wire from the solenoid to the ammeter will be by itself I believe on the positive terminal of the ammeter. The wire from the alternator, the wire to the ignition switch and the feed to lights all go together on the opposite side or connected to it via the terminal block if you are using that. I know JMOR has a diagram that shows only the alternator wire by itself on one side but that method only shows alternator charge and does not read any load amperage.
That way you have it will show charge. So either your battery is well charged or I think the better guess is by Mad Farmer. I suspect you have a 3 wire alternator and your excite circuit, spade terminal 1 is not connected. It should be fed by the switched ignition with a diode or dash indicator lamp in series. And the spade terminal 2 should be jumped to the back terminal stud on the alternator.

 

[JMOR]

A couple of many ways to do a conversion:

https://imgur.com/eUCpm9n

 

[Philco]

All my wiring is exactly like the diagram that JMOR provided in his diagram execpt the ammeter wiring. Mine is totally opposite as I followed a Youtube viseo provied by Dan and Rachel Gingell; title of video is >>

Ford 8N SIDE Distributor Twelve Volt Conversion, 1950-1952 Model Years, Easy How-To Video.​

In fact, it was Dan Gingell that did the 12 volt conversion on my tractor about 1995. This time I'm putting a new ammeter on. Dan and Rachel suggests putting the redwire from the solenoid (where also the positive battery cable attaches) to the BAT+ side of the ammeter. Then the other wire on the Load side of the ammeter goes to the alternator, single wire system alternator. And not so important here, but the yellow wire from the on/off switch attaches to the ammeter positve side , BAT+. This is how I wired it up which is opposite from the diagram. Question is, does it matter? Current still flows through. Today, using the tractor for the first time to mow the grass, I notice the needle on the ammeter drops to the negitive 30 side of the amp when it is in use. And more importantly, before I truly used the tractor for the first time, my voltage on the battery tested 12.67 volts. After 3 hours of mowing the grass, I tested the battery again, and it reads 12.95 volts. So the alternator is charging the battery, and I'm happy with that. But why the frown on the ammeter as it reads -30?

Cannot tell you guys how proud I am of my 8N tractor as it makes my home look good during the grass growing seasons, and winter tme plowing.

Philip

 

[stdsch40]

Switch the wires on the ammeter, and it will read +30. The MINUS 30 might mean a drain of 30 amps. The single wire from the alternator should show +14vdc if its charging correctly and motor rpm is adequete. Maybe you do have a 30amp draw for some reason like lights, coil, whatever. But obviously you are getting closer to figuring it all out, which is a good thing.

 

[used red MN]

Switch the wires on the ammeter,

If that is not clear, that means swap them side to side. Should be pretty straightforward if you only have one wire on each side.

 

[Btzj02]

All my wiring is exactly like the diagram that JMOR provided in his diagram execpt the ammeter wiring. Mine is totally opposite as I followed a Youtube viseo provied by Dan and Rachel Gingell; title of video is >>

Ford 8N SIDE Distributor Twelve Volt Conversion, 1950-1952 Model Years, Easy How-To Video.​

In fact, it was Dan Gingell that did the 12 volt conversion on my tractor about 1995. This time I'm putting a new ammeter on. Dan and Rachel suggests putting the redwire from the solenoid (where also the positive battery cable attaches) to the BAT+ side of the ammeter. Then the other wire on the Load side of the ammeter goes to the alternator, single wire system alternator. And not so important here, but the yellow wire from the on/off switch attaches to the ammeter positve side , BAT+. This is how I wired it up which is opposite from the diagram. Question is, does it matter? Current still flows through. Today, using the tractor for the first time to mow the grass, I notice the needle on the ammeter drops to the negitive 30 side of the amp when it is in use. And more importantly, before I truly used the tractor for the first time, my voltage on the battery tested 12.67 volts. After 3 hours of mowing the grass, I tested the battery again, and it reads 12.95 volts. So the alternator is charging the battery, and I'm happy with that. But why the frown on the ammeter as it reads -30?

Cannot tell you guys how proud I am of my 8N tractor as it makes my home look good during the grass growing seasons, and winter tme plowing.

Philip

The conversion kit I bought from that web site illustrates the incorrect way to wire the amp meter. In the illustration they sent me the amp meter was wired to only read the output of the alternator not, like the original OEM wiring, to measure the flow to and from the battery. I did contact Dan regarding the drawing error and they were not interested in what I had to say. It is possible that the amp meter would read 30 amps if the alternator was putting out 30 amps.

 

[JMOR]

The conversion kit I bought from that web site illustrates the incorrect way to wire the amp meter. In the illustration they sent me the amp meter was wired to only read the output of the alternator not, like the original OEM wiring, to measure the flow to and from the battery. I did contact Dan regarding the drawing error and they were not interested in what I had to say. It is possible that the amp meter would read 30 amps if the alternator was putting out 30 amps.

I do understand..............I drew up diagrams for more than one company/requestor, according to their request.........and then I also drew up my own, according to coming as close as possible to N tractors, but converted to 12v, Neg gnd, as well as just like 9N, 2N, and 8N, 6v, Pos gnd.. So, everything is out there somewhere for one to select as suits them.

 

[OldBlue61]

@JMOR I used your wiring diagram when I rewired my tractor, and my ammeter works great. Thank you.

 

[Philco]

I'm not an expert on Ford 8N tractors but do know wiring. First off the single wire from the alternator would be a POSITIVE if as you say the tractor is NEGATIVE ground. Suggest you verify the single wire is in fact POSITIVE, and if so connect it to the +ve of the ammeter. Hope that you understand that ammeters are POLARITY sensitive. Start there. A voltmeter is also POLARITY sensitive, if you decide to change the ammeter for a voltmeter.

That's exactly how its wired; that is, the one wire alternator wire goes to the POS side of the ammeter, and the wire from the solenoid goes to the negitive side of the ammeter. The ammeter needle still hovers at the zero mark when the tractor is on and running hard. I will continue to check the battery's volts from time to time. I'm really not sure what the ammter is supposed to register when on, but all sreems well, so far.

Thanks greatly...Philip

 

[stdsch40]

Does your ammeter have zero (0) in the centre of the amp range with +ve and -ve on either side of the zero? Can you post a picture of it? As I mentioned earlier if the alternator is charging properly you would get a volt reading of 14 volts to ground (chassie negative). With a fully charged battery the ammeter wont show much amperage maybe 2 or 3 amps. If you turn the lights on the amps will go a bit higher or lower depending on the state of battery charge.

 

[Jim.ME]

If you used a 60-0-60 ammeter it is not unusual if the needle hardly moves, there is not much draw to that electric system, so it doesn't need to charge much. Even a 30-0-30 might not show much. As mentioned, monitor the battery voltage to see if in increases as the tractor runs.

This is the reason I use voltmeters on units with alternators, if the trouble shooting is to use a voltmeter to check the system, the system might as well have a voltmeter instead of an ammeter.

 

[Jim L WA]

Another thing to consider, if the ammeter you have has an internal shunt then you will see little movement.