12V Conversion questions

Soundguy · Jun 4, 2004

Simple.. it is a multi pole switch with one pole being momentary... in effect 2 switches. yet having seperate contacts as if 3 switches. that's how the isolation occours for the alternator. as for the solenoid hookup.. that is only true if you change out the solenoid on the 8n. The oem ford solenoid was 3 terminal, and the coil was internally hot.. the third terminal merely grounded the solenoild coil via the big tranny neutral interlocked thumb sized switch in the tranny top cover. A newer isolated 4 terminal relay is needed for the starter combo switch hookup.

Also.. we ( guys ont he ytmag board N-forum ) are a bit of purists... and generally like to keep our tractors as close to oem as possible. That usually means that we like to keep our oem one position ignition switch. And also, many do not convert to 12v unless they have a 12v accessory or implement. Also.. there are at least 2 alternator conversions out for the early fords.. one used an older alternator and a regulator.. the other is a newer unit.. 3 wire setup.. and is still serviced by NH.

Soundguy

Soundguy · Jun 4, 2004

Did you get the correct regulator? Sounds like no.

Gennies come in two basic types.. a circuit.. and b circuit.

Both have a cutout relay that keeps the genny from draining your battery when not charging. Both regulators need to be polarized to set the cutout relay.

Here is where they differ.. an A circuit genny has a field coil that is internally hot.. and the genny vibrating contact provides ground to the genny field.. thus letting it charge. Therefore on an a-circuit genny.. you can jumper the field terminal on the genny to ground and get max charge.. this is called full-fielding it.

On a b-circuit genny.. the field winding is internally grounded, and the regulator provides field current via the vibrating contact. To check a b-circuit generator, you jumper battery to field to giv max current to the field ( bypasses vibrating contacts ).. and that full fields the genny.. producing max charge.

Charging at 15 amps sounds like max charge for an early genny. The genny on my JD maxes at 7amps.. and the genny on my cub maxes at 11-14 amps.. while the genny on my fords max at 11 amps for the old b-circuit 3rd brush adjustable1 wire jobs.. to 20 amps for the later a and b circuit 3 wire jobs.

Check your manual to find out what type of genny you have. My 1966 IH cub happens to have an early 12v a-circuit genny.

If you know what type of genny you have you can test it easilly. While running, disconnect the field connection at the genny. Check with a vom between ground and the field terminal.. if you read any voltage.. it is probably an a-circuit. In which case you can jumper it to ground to get max charge. If you read no voltage... it may be a b-circuit.. in which case you could jumper it to the battery hot for max charge.

Keep in mind that these gennies won't like to be full fielded for any protracted length of time.. just enough to test.

Usually when I see a genny putting out max after a VR swap.. it is an a-circuit that has a wrong regulator, and it is grounding the field.. or it is that the insulation is damaged at the field terminal letting it ground out.. or something inthe wireing is shorted letting it ground.

The symptoms you mentioned of the battery dieing are consistant with an incorrect VR.. or one that has the cutout contacts either welded together due to not polarizing it, or just not closing because it was not polarized.
To polarize *many* but not all a circuit regulators and gennies.. jumper bat to armature ( may be called genny on old vr's ) for a second.. might make a spark.. this sets the field poles and determines polarity of the charge and polarizes the cutout relay. ( yes.. most gennies can be repolarized to charge either negative or positive ground.. but you have to watch out for the regulators.. the old ones were'nt isolated.. so best to leave them how they were from oem. )

Most b circuit regs and gennies polarize by jumpering batt to field for a second.

Do these polarizations with engine NOT running.. and caution.. polarizing wrong almost always destroys the regulator... That means that if you jumper batt to field on an acircuit regulator.. you just lost 30-40 bucks in a puff of smoke.

Any time a genny has been rebuilt.. or a new regulator has been added.. or if either has been removed.. or the genny has been dropped or banged with a hammer.. or if it has set a protracted amount of time.. it is best to repolarize the system.

Soundguy

Soundguy · Jun 4, 2004

I'll add one more thing.. many of the old gennerator systems incorporated resistors of different values into the ignition and light switches. This was to 'tickle' the generator into putting out more power when the lights were on.. and less when it was only the ignition running...

You will need an oem schematic of your tractor to determine this.. and also check to see that you still have the oem genenrator.. etc.

lots of things get changed in 60 years..

Soundguy

nobull1 · Jun 4, 2004

Quote
Also.. we ( guys ont he ytmag board N-forum ) are a bit of purists... and generally like to keep our tractors as close to oem as possible. That usually means that we like to keep our oem one position ignition switch. And also, many do not convert to 12v unless they have a 12v accessory or implement.

Soundguy
I have been over to a few of the vintage tractor sites and wonder why people convert to 12 v.On my 54 cub half of the parts for the generator were missing from years of people working on it /forums/images/graemlins/frown.gif.So we used to just charge the battery and could use it for a month or so before it went dead,not a good idea but that is what we did.When I decided to get the charging system working I went to alternator repair shop and had them build me a alternator that put out 6 volts,actually about 7 volts if I remember correct.This is a easy thing to do for them and it means your whole system is still original except for the alternator.I used a one wire and have to rev to about 1200 rpm to excite but can drop down to 400 and still charge.The people that built the alternator knew of the exciting problem and just put a different regulator in that required less rpm. I am amazed that people don't do this instead of switching to 12.The starter still works on 6 volt instead of 12 which has to be easier on it and no wiring to do. I installed the above type alternator about 6 years ago and has never missed a beat.

Soundguy · Jun 5, 2004

Yes.. I've seen 6v alternaots custom built.. as well as positive ground alternators. I've also seen generators from newer 12v tractors used in place of the oem 6v genny.. or even having the old 6v genny re-wound 12v.

As for the alternaotos.. I don't like 1 wire jobs.. it is too much of a cob/hack. Voltage regulators are easy to come by and install... The mid 80's hitatchi alternator on my yanmar 1700 uses a common 10 dollar chrysler vreg...

Also.. it is soooooooo easy to use a 3 wire and build in an exciter circuit... lotsa ways to do it.

Most guys that convert from a 6v genny don't go to a 6v alternaotr... they go ahead an go to 12 if they get an alternator. Most 6v gennies will be right behind a 6v alternator in amps produced.. and the genny will produce at a lower rpm using an old vibrating contact vreg.. than the 6v alternator using a low rpm regulator. A smaller than oem pulley on the alternator does offset this difference quite a bit, making them about even. On the flip side.. gennies are more tolerant of being hooked up backwards.. whereas alternators are NOT reverse current tolerant. Add to that that gennies can be polarized as either negative or positive ground, and back and forth... thet's pretty decent. Besides.. For gas jobs.. I like positive ground better due to the edison effect and spark plugs.

Soundguy

nobull1 · Jun 5, 2004

I would agree that the three wire has the potential to be a better alternator.When I got mine it was a one wire and that never came up about using a three wire.For the life of me I can't remember how they did it but it took only a couple of mins.and could be changed to 12 v for about 30.00 if wanted or required.The funny thing is a lot of the vintage tractor people, like you have said want to stay as much original as possible.In 7 or 8 years of following different sites I never seen anyone just upgrade to a 6 v alternator.This is a easy upgrade no wiring and just a bracket to make for mounting.The reason I posted was only really to ask why this was not done as it is so simple and you get low repair technology .Can't argue with anything you say in regards to tractor charging systems /forums/images/graemlins/grin.gif

RobertN · Jun 5, 2004

The selection of one-wire altenators is actually not bad. Just gotta look in a wider area. Rock Crawlers had this issue too. You get a Jeep out on Rubicon idling all day, 'cause that is about as fast as you can go over the rocks. So, they do not charge...

Some folks started working things out so they have one wire systems for ease of installation, and the ability to charge at very low rpm. It's another niche /forums/images/graemlins/smile.gif Stuff is availble through 4wd shops/magazines.

They do tend to put out more than we might need on tractors though. Some are rather beefy 100-150A jobbers, for good recharge after heavy winching or running accessories.

Premier even makes a lowrpm charge altenator with stuff built in to make it a stick-welder with 110v accesory plugs too /forums/images/graemlins/cool.gif
How about that for that field repair you gotta make /forums/images/graemlins/wink.gif My B-in-law has one on his Jeep; it is pretty dang cool!

Soundguy · Jun 6, 2004

( Some folks started working things out so they have one wire systems for ease of installation )

Choosing a 1 wire job over a 3 wire job for 'ease of instalation' is like choosing masking tape over duct tape. The 'real' work comes in mounting the alternator... Hooking up two additional wires ( one simply jumpered between 2 terminals on the alternator ) isn't a big deal.. or at least.. shouldn't be.

Soundguy

Soundguy · Jun 6, 2004

( it took only a couple of mins.and could be changed to 12 v for about 30.00 if wanted or required )

Might have been something as simple as a change from parallelled to series winding connections.

And most of us vintage tractor purists would rather have a 6v genny than a 6v alternaot on our machines. If we go alternator.. might as well go 12v.

Besides.. gennies are pretty easy to maintain.. and not too much to go wrong. I can pull a genny apart, change brushes dress the mica on the com'tator and re-bush in a few minutes on the bench.. and unless the field or armature winding is bad.. that's all there is to the internals. An alternaot is another ball of wax.. Internal vr's diode packs.. etc... not very user serviceable compaired tot he genny.. which more or less just consumes brushes every 20 years...

Soundguy

upgw · Jun 6, 2004

Per the manual, looks like I have an 'A' circuit generator. Two wires from the generator to the regulator. Here's a neat page on another guy's 130, it pretty much sounds like mine starting:

http://www.oldoakfarmalls.com/130Page.htm

I was up at tractor supply and while they were out of 6V batteries, they did have 8 volt ones... strange.

Per the service manual, the missing fuse and switch was all for the lights, which it doesn't have any longer, so perhaps the current wiring is correct, seems like something is going on in the regulator.

- Patrick