Voltage regulator?

Selahdoor

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You've either got a corroded connection between A and the positive battery rail, or a bad regulator. If the voltage at terminal A is 15 volts and the regulator is still pulling the F screw down at all, that regulator is sick.
Going to go ahead an order a voltage regulator and brushes. And look for the slip rings while I am at it. Looked at those again today, while I had it apart, and the grooves are probably worn close to all the way through. Very deeply worn. Bearings are fine. And apparently, so, too, are the windings and all the rest.
 

BeastMaster

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Just to be sure you are measuring the A voltage as seen by the regulator itself, you might wanna make another test thingies like the one you just made and connect it to the other brush screw on the back of the alternator. The schematic shows ie being internally connected to the A connector pin.

What I am trying to rule out is a bad connection at the connector before you go to the trouble of getting a replacement regulator. If you are still seeing overvoltage at the brush screw itself, you know good and well that's what the regulator is seeing.

And look at the regulator itself...is it's ground to the alternator frame good? You won't see that until you physically remove the regulator, but if it's ground is up a couple of volts above real ground, it's regulation will be just that much higher too...and remember the armature winding current is flowing into that ground.
 
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Selahdoor

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I may take all that apart again tomorrow, just to get eyes-on, and see if there is any corrosion.

But I'm convinced. I need the regulator, brushes and slip ring.


Does anyone know the part number for the slip rings? The brushes will come with the regulator.
 

BeastMaster

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Well, looks to me like it's nailed...and you never needed any of those fancy testers.

Just an understanding of how it works.

For me, it's Grandpa's old Triplett 630. Close enuf for most things.

Hope you get a good night's sleep.
 

Selahdoor

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Well, looks to me like it's nailed...and you never needed any of those fancy testers.

Just an understanding of how it works.

For me, it's Grandpa's old Triplett 630. Close enuf for most things.

Hope you get a good night's sleep.
Oh yeah! Going to sleep good tonight!
 

Selahdoor

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Just to answer this.... Yes. It's an output from the alternator that's already being told to put out too much voltage.

It's a symptom, an indicaton, but not the cause.
Thank you.

And I just realized that the difference is not between 15.6 and 12.3.

The difference, while running, is only between 15.6 and 14.2.
 

BeastMaster

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That voltage is hard to measure accurately, as it's a pulsating DC as the armature poles pass by the stator poles, with it's frequency in the hundreds of hertz, a function of engine rpm.

Even "true RMS" meters can have problems measuring it precisely.

And to make it worse, it's only one of three phases.

But the presence of pulses here is a sure fire indication the rotor is spinning.
 
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onetonjohn

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Funny, I've got a fairly strong electrical background, and I still don't understand exactly how this circuit works.
 

Selahdoor

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Thinking further about this...

The slip rings are pretty deeply worn. And the brushes are awfully short.

I thought I'd like to do one more "test".

Brushes at napa are only 8 bucks. I called and ordered them. They'll be in, this afternoon.

I think I am going to put new brushes on it, and see what happens.


Kinda torn, this morning, though. I could just take the regulator off the other truck, and try the whole thing. But 1.) I don't know that the brushes are any better on that one, or not. and 2. If only new brushes on this one, "fixes" it, then I will have wasted a bunch of time. Instead of going to all that work, and then having to put the old regulator back on the old truck, in the end, anyway, I think I'll just wait on the new brushes, and swap only those, and see what happens. If that doesn't fix it, I'll know I need a new regulator.

I still have not found a part number for the slip rings for this. (Or a complete rebuild kit that looks like it is worth anything.) Regardless of whether the new brushes actually fixes the problem, or it takes the regulator as well... I'll still have to find the right slip rings and replace those.

I have found a new motorcraft regulator. I'll go ahead an order that, this afternoon or evening, depending on my findings.
 

BeastMaster

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I would just swap the regulator, it’s not gonna hurt anything and it will help narrow things down.
I'd do it too just to rule it out.

Regulators don't fail very often.

Or, at least not nearly as often as those old mechanical ones 50 years ago did

However connections are quite failure prone, despite their apparent simplicity.

Corrosion causes the damndest hard to find failures by insertion of resistance or noise into a circuit that looks to be perfectly good. Some are so.clever that one would think it was divinely inspired.
 

hacked89

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Cool thread.
Here's my 2cents.

Your first problem was the glow plug controller clicking when in the run position. Most of the time this is from an inop glowplug or issue with the wiring or connection to the glowplug. I know you got new glowplugs but it's not unheard of to get a bad one or multiple bad ones. My guess isn't that you are losing prime it's the condition above as supporting evidence.

Second, you can have up to about 15.8v and still be normal. Easy test for bad regulators. Run the truck at idle and multi the batteries. Watch were it stays. I know you've done this multiple times in the thread but in this test we want to see it back to back with the next part. Then get another person or turnbuckle and raise the idle and hold at 1500rpm. If you read less than 15.6v I think you have a bad regulator. If you stay at 15.6v I think you have a good regulator.

In the latter scenario, I believe you have an issue in the glow plug circuit, it's causing the clicking, and the intense draw from the controller is causing your wonky gauge to jump around.

Sent from my SM-G955U using Tapatalk
 

BeastMaster

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I think Selahdoor's voltage is too high.

https://batteryuniversity.com/learn/article/charging_the_lead_acid_battery

Actually, his is off the chart.

I don't have enough experience with the glow plugs to offer much advice. I know mine are new Berus, appear to be working properly, and cycle about 6 times after an initial warmup time of about 10 seconds. Their heavy current draw does load the batteries enough to dim lights, nudge the voltmeter, and influence the sound of my Carter electric fuel pump.

I've grown to depend on the audio cue from the pump as to when to crank: Right upon the onset of cycling.

I'm not a mechanic, but I do a lot of microcontroller and interface design stuff, so I probably don't use the right trade language. That's the reason I am here...I am quite ignorant of the mechanical stuff.

But occasionally someone gets hung up on something in my arena, I'm only too happy to share, as others have shared with me. Oh, God, what a mess I had several years ago when I bought my IDI van off of Craigslist, to discover no local mechanics seemed to know how to fix it. It turned out my problem was a bad circuit in my PSOM, and I was guided right to it by a few other people who took the time to share their knowledge. So, this is what comes from the seed they sow.

I know one of the things I must do is visit TheWesPaul and beg him to bless my IDI, as I want my van to be with me the rest of my life. This is a wonderfully elegant design. I get the feeling if Wes goes over it, he can make it better than it was coming off the showroom floor.
 
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Selahdoor

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The 15.6 is boiling the batteries.

Barely noticeable, but they bubble, and spit out liquid, if I have it running for too long.

Got the brushes. Just got home.

Tomorrow, I am putting the brushes on, with the regulator that is already on there, then I am going to test again.

If it is *better*... I'll order the slip rings and see if that completes the repair.

If it doesn't make any difference whatever, I may just get a new alternator...
 
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