I have some 8N Generator questions.

Gentlemen,

Warning: I am not an electrician. Therefore this may get frustrating for those knowledgeable in troubleshooting Ford tractor electrical components. Also, I got my 8N service manual today, from YT, and find there to be very little information on generators in this book.

I have a 51 or 52 8N, (for the life of me I simply cannot make heads or tails out of the complete serial number on this machine).

I think my 6 volt generator is not generating properly. ASSUMING that my ammeter is working correctly, the only time it indicates a positive charge is when I have my 6 volt battery charger on the battery. I do get a distinctive negative charge when I turn on the lights.

I have tightened the belt. I have approximately 1/2 inch of flex in the belt. I have ran the engine at various RPM's to try and get a positive charge indication out of the ammeter.

I have read other posts here advising folks that digital multi-meters are unreliable when working with generators. I proved that to be true with mine, (readings were all over the place). I dusted off my old analog "multi-tester" and am now ready to ask some questions.

I have attempted to upload two pictures of my generator. My hope is that, due to my inexperience, by looking at these pictures someone can answer these questions.

Can someone please identify if I have a two brush or three brush generator? Some of my research indicates that some years may have two, some three, brushes?

Can someone please provide me with the correct terminology for the electrical post closest to the engine and for the outboard electrical post?

Can someone please provide the correct terminology for the electrical post on the backside with the red wire?

Is the amperage test for the six volt generator described in the Ford Tractor Shop Manual, beginning on page 61, the same for the 8N 6 volt generator? If so then I should be able to use my analog multi-tester to see if the generator is charging, correct? Especially if I have the correct terminology of the electrical posts on the generator?

I hope all of this makes sense. I have tried to be as clear and concise as I can.

With That,

Thank you for any help you can provide.

Larry Wallace, (Tractor Rookie)

Found this in my saved 8N stuff. Hope it helps.

If you can't enlarge this; The wire on the back of the generator is the ARM (ature) post. The top one on the side is the FIELD post. The bottom one on the side3 is the GROUND post.
Google "8N wiring diagrams" or "8N generator wiring diagrams" to get more pictures.

Bob Purington,

That is hands down the best and most useful wiring diagram I have seen to date. Thank you!

That answers at least two questions. I will do as you suggested and continue searching for more information but with different wording.

Again, Thank you.

Larry Wallace, not as dazed-n-confused Tractor Rookie.

Bob Purington,

In order to clarify, (looking at my submitted picture), the post closest to the engine, with the white wire, is the GROUND.

The outboard post, furthest from the engine with the black wire, is the FIELD.

Correct?

Thank You Sir!

(quoted from post at 23:22:48 04/26/13) Gentlemen,

Warning: I am not an electrician.

<snip>

I hope all of this makes sense. I have tried to be as clear and concise as I can.

With That,

Thank you for any help you can provide.

Larry Wallace, (Tractor Rookie)

Click to expand...

You may not be an electrician (let alone electrical engineer) but you know how to formulate the problem and reason logically and that's 99% of the battle. The simplest and quickest solution is to take the generator to a good electrical shop and having them bench test it for you.

TOH

(quoted from post at 10:08:45 04/27/13) Bob Purington,

In order to clarify, (looking at my submitted picture), the post closest to the engine, with the white wire, is the GROUND.

The outboard post, furthest from the engine with the black wire, is the FIELD.

Correct?

Thank You Sir!

Click to expand...

would say that you are 'bass-ackwards'. Look closely and you can see an insulator under the Field terminal (white) and no insulator on the Ground terminal(black).

Thanks TOH, I appreciate the compliment and the advice.

Written communication can be an aggravating thing. Even as hard as I tried to be clear in my description of the problem I still misspoke in one statement. Instead of "negative charge" I should of used the word "discharge".

Larry Wallace, learning daily Tractor Rookie.

JMOR, yes, I think I see and understand what you are referring to.

I will try to verify it with a look at the physical generator just to ensure the lighting in my pic did not deceive me.

Thank You.

Larry Wallace, Tractor Rookie.

ps.. don't waste the time and $$ just yet taking the genny to get it bench tested.

you can do most of what they do setting right on the tractor.

pull belt off.. ground the field ont he genny and apply bat hot to the armature.

if ti spins, it SHOULD charge.

occasionally you get one with a field fault that will weakly spin, but not charge.

after that test put belt back on.. make sure you have reg armand field terminals hooekd correctly at reg and genny.. start up.

if no charge. ground field on genny. if no charge.. jump bat and arm (gen ) on reg.

post back

Soundguy, thanks for the guidance.

In order to avoid "too many cooks in the kitchen" do you concur with JMOR that, looking at the submitted picture, that the FIELD terminal is closest to the engine with the white wire?

In my inexperience I'd hate to make the situation worse.

Thanks Soundguy.

Larry Wallace

(quoted from post at 15:31:13 04/27/13) Soundguy, thanks for the guidance.

In order to avoid "too many cooks in the kitchen" do you concur with JMOR that, looking at the submitted picture, that the FIELD terminal is closest to the engine with the white wire?

In my inexperience I'd hate to make the situation worse.

Thanks Soundguy.

Larry Wallace

Click to expand...

White is field, black is ground, big one one the back is arm in your pic.

If that insulator JMOR discussed is broken down and cracked, your field is shorted to the case. 1/4" fuel line makes a decent replacement.

my screen on this pad is too small for me to make the determination.. I'll elave that to someone with a large monitor.

what can be said is that of the 2 side posts.. one will have an insulation grommet.. the other won't

the insulated one is the field.

will be plain to the naked eye..

Roger copy on the small screen.

Here is where I am at this time. The FIELD terminal is the one closest to the engine. I think I proved it or I just got lucky. As you suggested, after removing the belt, I "grounded the FIELD terminal and applied battery hot to the armature". It did spin. I put the belt back on and ensured white on FIELD, black on GROUND, and red on ARMATURE, terminals. Cranked her up and, ASSUMING my ammeter gage is working properly, the generator is not charging. It does read a discharge but not a charge.

Next is "ground FIELD on generator". Are you recommending I put a jumper wire to GROUND to FIELD or just any ground to the FIELD terminal?

Another question: "Jump battery and armature (gen)on regulator". The voltage regulator correct? If so, is there a specific terminal? I have three with a yellow, red, and white, wire coming off of it. There is also a distinctive ground on the voltage regulator.

Thanks Soundguy, I do appreciate your time.

Larry Wallace.

here we go.

ground field.

ground is ground.


you could run an 80' wire from battery ground to the field. or just use a screwdriver to short the post to the case housing.

ground is ground.

next I said to jump bat and arm at the reg.

exactly that. jump bat and arm... arm is sometimes called gen.


if you don't know what's what on the reg.. cheat.

run a wire from bat hot to the armature on the back of the generator.

it won't know the difference... jumped at the reg or the long wire.

same effect. for all intents and purposes.. all points of a conductor are at the same potential... again.. for this test. for large draws and long runs.. you CAN get differences in potential... but not for this test...

Soundguy,

Having done what you have suggested with no positive result I guess the next step is to take the generator and have an electrical shop look at it and maybe get it rebuilt.

Just in case I missed an important step let me run through what I understood you were wanting me to do.

With the first test I did get the generator to spin.

Second test: I took a jumper wire and grounded the FIELD terminal. I took it off and started the engine and checked for charge. Brought it up to half throttle with no result. Was I to leave the jumper wire on?

Third test: With the engine shut off I jumped the battery (hot) to the arm. I took off the jumper wire and started the engine and again with no charging result.

I hope I understood and did everything as you explained it.

Thanks to you, Jaymor, JCinKY, Bob Purington, for the help today I learned quite bit about 6 volt generators today.

Larry Wallace.

Your headed in the right direction, but you need to perform the tests with the tractor running. As for the wire...I'd ditch it and use an insulated tool. Screwdriver will work.

You will be full fielding the Gen and should only do so for a few seconds to avoid damage to the system.

Start er up and perform each test while watching the ammeter. You should peg it out during one of them.

He gave you great advice. Helped me out with the same sorta issue.

both jumpers in place with engine running at speed. If you jumper generator ARM directly to battery hot, do not expect ammeter chg indication, as you will be bypassing the ammeter. Better to jumper at VR at Batt/Arm terminals ( yellow to red) as then ammeter still in charge path.

JMOR, Ah, now I see where I screwed up. Useful information, I will try this ASAP.

Thank You.

Larry Wallace

JCinKY,

I'll keep trying. Yeah, Soundguy always give great advice. I have a great amount of respect for him and have always been impressed with his projects and expertise.

My problem is coming up to a level where he can penetrate my hard head.

I ain't just a BS'ing when I say "Tractor Rookie".

Thank You.

Larry Wallace

nope.. you missed it.

you must start the engine with the field jumped to ground.. then check for a charge while it is still jumped.

if no charge. leave the field jumped to ground, and ALSO jump bat to arm.

IE.. both jumpers in place AND engine running and genny spinning.

then look for charge on meter / battery.. etc.

jumpering field to ground with engine not running does nothing.

I have been following the discussion because I have the same problem. 1950 8n sidemount 6 volt with an ammeter showing no charge.
I jumped field to ground and started the tractor. No charge. I jumped arm to hot and got no charge.
When I removed the arm to hot, the ammeter showed a high charge rate. When I removed the jumper, it went to zero charge. Suggestions?