Test Generator - 1971 Ford 3000

[jascott]

I am in the process of fixing up a 1971 Ford 3000 Gas tractor.

The previous owner had replaced the generator w/ an alternator, that appeared to be overcharging the battery.

I purchased a new generator and installed it, but I don't think it is working.

Engine off battery voltage 12.9 volts.
Engine running 1500 rpms 12.3 volts. ???
Engine running no wires connected to generator - generator voltage 2.9 volts.

Any specific steps to check things out? I have also replaced the voltage regulator..

Thanks,

JS

 

[FULLPULL]

When you remove most generators from a tractor and reinstall it may need to be polarized . I cant give you the steps as it has been a while since i have done it . But it has to be done or it wont charge .It is touching a wire to a terminal and i dont want to tell you the wrong ones. You can also do a search on polarize a generator there is some disscusion on the subject.

 

[jascott]

That did it. Once I figured out how to polarize it, the system seems to be charging now. I am registering 13.8 volts at 1500rpm.

To polarize it, I lowered the harness connecting to the VR about 1/2 way and shorted the B and F connectors. Battery to Field. It sparked, and that was it.

Thanks,
JS

 

[Mighty Dodge]

There's several articles on 2 and 3 brush generators on Yesterdays Tractors website.

Yesterday's Tractors - Tractor Generators

M.D.

 

[Soundguy]

Yep.. those lucas gens for fords are B circuit.. polarize field to battery.. that will also full field them for a current test too.

Older 8n gennies were a-circuit and polarized differently.

congrats on changing back to a generator system.. not many people are brave enought to do that.

soundguy

 

[Egon]

Did someone mention Lucas???

 

[Soundguy]

Did someone mention Lucas???

Indirectly, yes.

If it's a oem gen on a ford from 65 and up.. it's likely a lucas product, and if earlier than 65, it should be a ford gen.

soundguy

 

[bigmarty]

i just bought a 71 ford 3000 as well mine is not charging. an old timer said to ground the field. i am a 33 year plus mechanic on cars and light trucks.
not much experience on gens.

 

[Soundguy]

the old timer gave you a good way to cook a 40$ regulator. He's thinking about the older 8n vreg /genny that is A circuit. back 47-52..

all fords 53+ and your 3000 uses a B circuit system. the reg provides POWER to the field post on the genny.

to test a B circuit genny. first motor test it.

slip belt off. jump battery + to field and armature. genny should spin. if it does.. continue on to next step.

slip belt back on.. put meter across battery.. should be 12.6 or so static.

start tractor.. get to 2/3 to 3/4 throttle.

voltage should be 13.8-14.7

if no increase.. jump bat + to field... that should make charge voltage jump. if not, jump bat to field and arm. if voltage onthe bat comes up.. replace regulator.

 

[bigmarty]

hey thanks i did find out that i have about 28 volts unregulated coming in to regulator. if i jumper to the battery plus side i get about 14 volts.
this is a lucas system with a 5 wire set up. i have only seen 3 or 4 wire , one is a dedicated ground. these lucas regulators are a bit hard to find.
i need the tach drive off of the gen so i want to keep it. otherwise i would put a one wire delco on it.
any more help would be great
thanks
bigmarty