Ford 3000 not charging below 1500 Rpm

Hi Folks

Im having some trouble with my 69 3000. It has the 22amp generator on it and its been doing a good job until lately, but now it wont charge unless im above 1500 rmps and then it charges like normal, around 13.9V or a lil more. Im rarely over 1500 showeling snow, so unless i charge the battery with a charger, its always low. The belt is new and tight, so its not slipping.

im wondering what the main suspects are for this issue, the brushes in the generator? or the voltage regulator?

I also have some newer alternators im considering putting on instead, but i really would like to keep the tach/hours intact. Is it possible to hook up the tach anywhere else on these fords?

Thanks for help and suggestions.

How do you know that it doesn't charge below 1500? Does the charge light come on?

Yes, the charge light comes on, but i have also measured with a voltmeter to be sure.

Measure the voltage carefully at the generator or regulator as you go up and down past the 1500 RPM point and try to gauge
what that "switch point" is. It could be as simple as a voltage regulator adjustment. Without looking in the book, I wanna say
that it's in the low 13 volt range for a spec. Let me know what you find.

If it's not correct, in the old days the natural response then would be to replace the voltage regulator. With the quality of
parts coming from offshore nowadays, I'd be inclined to try and adjust my old one before I bought a new one.

Hi again

Just been out measuring the voltage again

it seems to start charging at a pretty specific rpm, seems to be pretty much 1450-1500 rpms. Before it reaches that rpm, i measure 0.2 volts at the generator even at lets say 1400 rpms.
at 1600 rpms it produces around 13.5v, 1800 rpms - 14.5v, at 2000rpms i briefly saw 15.1V but it went down again to 14.9v.
So its slightly overvolting isnt it? or is this normal for these kinda setups?

I also noticed another thing, most of the times when i let the throttle down again past 1450, it stops producing voltage, but once in a while it will keep producing even at 900rpms.

So what does this mean? sticky voltage regulator?
I never adjusted any voltage regs, but if its fairly easy i can make an attempt.

(quoted from post at 14:51:34 02/21/21) Hi again

Just been out measuring the voltage again

it seems to start charging at a pretty specific rpm, seems to be pretty much 1450-1500 rpms. Before it reaches that rpm, i measure 0.2 volts at the generator even at lets say 1400 rpms.
at 1600 rpms it produces around 13.5v, 1800 rpms - 14.5v, at 2000rpms i briefly saw 15.1V but it went down again to 14.9v.
So its slightly overvolting isnt it? or is this normal for these kinda setups?

I also noticed another thing, most of the times when i let the throttle down again past 1450, it stops producing voltage, but once in a while it will keep producing even at 900rpms.

So what does this mean? sticky voltage regulator?
I never adjusted any voltage regs, but if its fairly easy i can make an attempt.

Click to expand...

hat 0.2 volt is very strange, but I'll let Bern continue.

Do the test again, but this time compare voltage at both the output
(A) terminal as well as the field (F) terminal. If the field voltage drops
to zero whenever the output voltage does, you have a regulator
issue. If the field voltage stays up when output drops, you have an
internal genny issue.

This may sound crazy I am wondering if brushes are just about worn out.

Doesn't sound crazy at all. Worn brushes are one of the main reasons for the advent of alternators.

Thanks again for your help.

I think i might have gotten lucky here.
I went to measure the F and A terminal and i noticed all the connectors for the voltage reg was a bit loose, so i pulled them off, and oh my, they were seriously cruddy. I cleaned them all up and gave them a lil squeeze for them to stick on better and now the charging system is acting totally diffrent.

It starts charging now at around 900 rpms, right around 13v and seems to gradually go up til around 1200 rpms where it seems to max out at about 14.8v.

When i let off the throttle, it goes gradually down to around 800rpms and low voltage of 12.5 before warning lamp comes on and it kicks on to battery voltage it seems like (on F terminal)

This pretty much how i remember it used to be before my problems if i go by memory on when the warning light went off and on. Does it sound like a somewhat healthy system?

When i give it throttle i sometimes see numbers of 15.2v but only very briefly before it goes back down to high 14's, should i be concerned by this high output? im not sure whats acceptable numbers for this setup.

Would be great to have it to generate power even at idle, but the 5000 i had before didnt do that either, so is that common for these tractors, or can it be improved somehow?

My 3000 idles fairly low, at about 600rpms, whats considered the sweet spot on these?

Im hoping this isnt just a fluke, but i stopped and started and ran it around all day, and it seems consistent, but i will of course monitor it for the next days/weeks to see that its really charging.

Sounds like it's operating normally now. You'll never get much if any output at idle, nor should you need it unless you plan on letting it idle with all the lights on for hours at a time.

15.2 volts is a little high, but if you only see it briefly, I would not get too excited. 15 plus continually will boil some of the water out of the battery eventually.

Alright, sounds good.

Hopefully it keeps working like this and no more flat batteries.

Thanks again for all ur help