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JD A
:

Can't make Alternator charge

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Mike Whitman

03-17-2001 10:38:11




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I rewired the alternator/external voltage regulator on my tractor and can't seem to make it charge. I wired according to info posted here and took some measurements (after it didn't work).

Here are my wiring connections:
1. Negative Battery post to ground
2. Postive Battery post to starter post
3. Starter post to ammeter post #1
4. Ammeter post #2 through switch&fuse to lights
5. Ammeter post #2 through indicator light&Ign switch to "I" terminal on external voltage regulator
6. Ammeter post #2 to "Bat" post on alternator
7. "S" Terminal on external voltage regulator to "STA" post on alternator
8. "F" Terminal on external voltage regultor to "FLD" post on alternator
9. "GND" post on alternator to frame

Those are my connections. After completing the wiring, upon activation of the ignition switch, the indicator light would illuminate (tractor not running). After starting the tractor and activating the ignition switch again, the indicator light still illuminated (I think should have gone out if charging). At no time has the ammeter indicated "charge". After taking some measurements with my meter, I bypassed the indicator light to see if that was causing a current limit situation to the "I" terminal(by wiring "I" terminal to +12v starter post). It seems after doing this, that the indicator light will no longer illuminate. I checked and the bulb is still good. Did I blow the regulator ? How can I test this setup. I had the tractor at a very fast idle.

My measurements were (w/tractor running):

BAT STA FLD IGN SW Position
12.5 .047-.065 .030-.022 OFF
12.5 .230-.275 .450-.470 ON


Thanks for any ideas/suggestions,
Mike

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Chuck

03-19-2001 04:48:08




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 Re: JD A - Can't make Alternator charge in reply to Mike Whitman, 03-17-2001 10:38:11  
the best choice in alternator's is the one wire with built in regulator...is GM model...



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george (keoke)

03-18-2001 07:56:42




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 Re: JD A - Can't make Alternator charge in reply to Mike Whitman, 03-17-2001 10:38:11  
Mike, assuming that you have a neg ground system and also assuming that by #1 post on amp meter you mean the MINUS side of the meter, then all connections EXCEPT the charge light are correct.
On the meter, the plus side of the meter stud gets the heavy (10 gauge) wire from alt and all load taps to the tractor. The minus side of meter should only have one wire going to hot side of bat.
On the (two terminal) charge light, it should be in series between the ignition switch and the "I" terminal of the regulator. Also, if field exciter current flowing through the bulbs filiment is inadquate (often) then you must put a 10 or 15 ohm resistor in parallel (across both lamp terminals) to insure adequate current flow to alt field for the charging process to start working.
When alt charges, a A/C voltage from alt stator (S term) will close a relay in reg. This in turn will apply bat voltage to backside of charge bulb making it positive on both sides thus putting it out.

Hopes this helps,
Keoke

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Mike Whitman

03-19-2001 10:28:50




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 Re: Re: JD A - Can't make Alternator charge in reply to george (keoke), 03-18-2001 07:56:42  
Keoke

1. Yes, 12 volt negative ground
2. I didn't look at post markings on ammeter just saw discharge when lights were on and tractor not running therefore figured was wired correctly
3. I put a light bulb (charge light) between "I" terminal on voltage regulator and a toggle switch (ignition switch)
4. Thought current might be limited through filament so bypassed by tieing "I" terminal to +12 volts (i.e. 0 ohm resistor)
5. Assumed no relay in voltage regulator. Isn't it solid-state (i.e. transitor or something ?) therefore no "relay"
6. Though bulb would go out because no current going through "I" terminal. Maybe I'm way confused.

7. Do you know what the "A" terminal is for on the voltage regulator ? I have no connection to it

Any other insights ? I'm kind of new at this old technologhy.

Thanks,
Mike

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george (Keoke)

03-19-2001 11:46:18




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 Re: Re: Re: JD A - Can't make Alternator charge in reply to Mike Whitman, 03-19-2001 10:28:50  
Mike, the charge side is the plus side of all amp meters. On neg ground systems, almost all wires to meter go here. Minus side of meter has only the output/input wire (heavy gauge) from the battery. It is a general miscomception that amp meters show the charge rate of the alt. This is not true. What the amp meter really shows is what is left of the alt current AFTER all the loads have been satisfied. In other words what the meter shows is only the alt current that is left and going to the battery only. Amp meters can only read current that cross completley through them.
On the voltage regulator, the original unit had two relays (field & voltage). A solid state replacement, of course has none, but does the same work with transistors. You can tell the difference, the relay types have a raised covers and solid state units have flat covers.
Terminal id and mounting flanges are the same for both.
Now the good part. The "A" terminal is for providing alt field current. This terminal goes to the plus side of amp meter. Also, it is the B+ from this terminal that puts the light out.
This is done by having the ign sw power up one side of the light and the "A" terminal the other if the alt charges. The two positives on bulb mean no current flow and thus no light.
Run a power lead to "A" and see what happens, this may be all you need. One thing for sure, is that there is no way that alt will work without it. If it still doesn't work put a jumper across idiot light. If it now works then then put 10/15 ohm resistor across lamp permanently to provide adequate startup field current.
If it still won't charge check out alt by running a hot wire directly to field term on alt. CAUTION, be sure to disconnect regulator before you do this test. If it charges then, with this field direct feed, and assuming all wiring is correct, then reg probably needs replacing since it is not it's job or feeding the field. Solid state regulators are UNFORGIVING when it comes to mistakes on wiring their inputs and outputs.
Though post is longer then I intended, I hope it helps.
keoke

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Mike Whitman

03-19-2001 13:08:02




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 Re: Re: Re: Re: JD A - Can't make Alternator charge in reply to george (Keoke), 03-19-2001 11:46:18  
Keoke,

I'm sorry but I still am confused as to the correct connections for the charge light, "A", "I", and ign. switch. Is this right ?

1. +12v to one side ign. switch
2. other side ign. switch to "I" terminal
3. +12v to "A" terminal
4. Light bulb between "A" terminal and "I" terminal
5. Add Resistor between "A" terminal and "I" terminal in parallel with light bulb if won't charge without it

Does the charge light indicate current flow between the "A" and "I" terminals ?

Sorry for taking so much of your time. I thought I understood more than I did.

Thanks,
Mike

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Ray M41

03-17-2001 18:55:17




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 Re: JD A - Can't make Alternator charge in reply to Mike Whitman, 03-17-2001 10:38:11  
Check your RPMs. I put an alternator on my tractor and couldn't get to charge. Took it back to the store and it worked fine. Put it in my vise and put a variable speed drill motor to it. It worked fine. The threshold speed was just below what was needed to make the thing charge. I put a smaller pulley on the alternator and it works a little better. But I now know what is the problem. Now when the battery is fully charged and the tractor idles down the light will come on and off.

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ED

03-17-2001 11:50:18




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 Re: JD A - Can't make Alternator charge in reply to Mike Whitman, 03-17-2001 10:38:11  
What kind of alternator, what model tractor?



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Mike Whitman

03-17-2001 14:58:00




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 Re: Re: JD A - Can't make Alternator charge in reply to ED, 03-17-2001 11:50:18  
1946 Model A
Alternator: Motorcraft, Model ?
Regulator: Matching for Alternator (I Hope)

This setup was on the tractor as I purchased it. It was never wired properly (I don't think). Past requests for information indicate this alternator was used on early (1965) Ford pickups.

Thanks,
Mike

P.S. This is definitely a retro-fit 12 volt conversion.



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