[AT] Neil Y. [Re: More on Charging Systems]

[Doug Tallman]

This was actually posted by Paul B but it was in reply to Neil. Some good
info here I've saved. I'll see if I've saved any other threads that he was
involved in.





Date: Mon, 11 Oct 1999 14:45:29 -0500
From: Paul Bazzetta <bazzetta at execpc.com>
X-Mailer: Mozilla 4.61 [en] (WinNT; I)
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To: antique-tractor at atis.net
Subject: Neil Y. [Re: More on Charging Systems]
Sender: owner-antique-tractor at newidea.atis.net
Reply-To: <antique-tractor at atis.net>

Thanks for the info.  I've performed the first tests.  Results follow:

This is on a JD 730 Diesel electric start.  This tractor has a 24 volt
starting/charging system.

More mix below.....


NeilY99370 at aol.com wrote:
> 
> Hi Phil:
> I think it was in the back of the Tractor Book.  It will be in the next
book,
> if I ever get it done.  (Harley-Davidson Electrics.)  I was too pooped last
> night, but I am more or less awake this morning. Here is my system.
> 
> You suspect that the charging system on your tractor is not working.  The
> ammeter needle just sits there and doesn't move.
> 
> #1 Before you start the tractor again, measure battery voltage and make a
> note of the value.  Digital multi-testers are really nice for this.  

Sorry, my meter is from the old analog world.  It uses a needle and
mirror.

Across both batteries it reads as follows:
Switch off - Batt = 25V
Switch "I" = 25V
Switch "L" = 24.5V (4 fender head lights & 1 rear)
Switch "B" = 24.5V (4 fender head lights)
Switch "D" = 24.5V (4 fender head lights dimmed)

>Start
> the tractor, run it faster than an idle and measure the voltage across the
> battery. If it is less than the first measurement, the system is not
> charging.  If it is higher, the system is working.  If it rises to 7 volts
> (six volt system) or 14 volts (twelve volt system) it is working properly.

I started the tractor and ran it @ 400 RPM (note: the "gen" light dims
but did not go out at 400 RPM)

Across both batteries it reads as follows:
Switch off - Batt = 25V
Switch "I" = 25V
Switch "L" = 25V (4 fender head lights & 1 rear)
Switch "B" = 25V (4 fender head lights)
Switch "D" = 25V (4 fender head lights dimmed)

> 
> #2 Assuming that the voltage doesn't rise, you want to locate the
non-working
> component.
> 
> Attach the jumper to the correct Multitester lead.  The red lead for
positive
> ground; the black lead for negative ground system.  Attach the other end of
> the jumper to a good ground.  With the engine running at better than a fast
> idle touch the other lead to the "A" terminal.  If the reading is one or two
> volts, you are reading the voltage produced by residual magnetism.

This is a negative ground system.  I placed the black (-) multitester
lead on a ground and the red (+) lead on the "A1" terminal.  Reading 6.8
Volts.

> 
> Most tractors use an "A" circuit, that is the field circuit is regulated "to
> ground."  A "B" circuit is regulated to field.  One end of the field coil is
> grounded.  Ford or Lucas is usually "B" circuit.
> 
> Assuming an "A" circuit, touch the grounded prod to the "F" terminal and see
> what happens.  If the voltage begins to rise remove the prod from the "F"
> terminal.  Don't allow the voltage to rise higher than the system. (7 or 14
> volts)


This is as far as I got.  I have not done this yet.  How high can I let
it rise on this 24 v system?

> 
> If the voltage rises when the prod is touching the terminal, then the
problem
> is in the voltage regulator.
> 
> If no voltage is present at the initial test, polarize the generator by
> touching the "A" terminal with a hot wire.  Try again.

What would be a hot wire?
  
	The generator has the following terminals:
		"A1"
		"F"
		"A2"
	The regulator terminals are:
		"BAT"
		"ARM"
		"FLD"
			
> 
> Still no output.  Disconnect both wires from the generator and try the test
> again.  If you now get a reading, the chances are that the wires were
> reversed between generator and regulator.  If still no reading, the
generator
> must be removed and checked.  A good generator will put out 30 volts open
> circuit with this test.
> 
> Most of the time regulators fail due to oxidized points. These can be
cleaned
> and the regulator put back in operation.
> 
> If you suspect that the generator may be a "B" circuit and it has failed the
> test you can run a jumper between the "A" and "F" terminal.  If the voltage
> begins to rise, the generator is a "B" circuit and is probably all right.
Bad
> or wrong regulator.
> 
> If, instead of a regulator you just have a cutout, you can still use this
> system for testing.  If you get output when touching the grounded prod to
the
> "F" terminal, then something is wrong with the switch on the dash board.
> 
> Do not run a three brush generator open circuit for more than a few seconds.
> 
> Neil
> 
> *



                                                      
           Doug Tallman                 
           dtallman at accnorwalk.com                 
           VGTCOA Ohio Regional Director  
               Greenwich, OH USA