[AT] Electrical/Generator Issues

[drupert at seanet.com]

Ben,

When you have an old tractor with a 6V/12V Bendix electrical charging
system that isn't working (and you have no idea why) I would start with
the assumption that everything is bad; that is, the generator, the
regulator and all the connecting wiring.

The generator is the place to start -

First, disconnect the two wires (from the regulator) to the generator.

Second (after making sure the battery is good) connect one end of a 
jumper cable to the battery ground post (i.e., if the tractor is positive
ground then connect the jumper cable to the battery positive post) and the
other end to the frame/mount/etc of the generator.

Third, connect one end of a short jumper wire to the generator "F"
terminal and the other end to the frame/mount/etc of the generator.

Fourth connect a DC volt meter (for 6 volt systems the meter needs at
least a 20 volt scale) across the generator terminals (i.e., across the
generator "F" and "A" terminals).  Note:  A good 6 volt generator, without
a voltage regulator connected up to it to control/limit its' output
voltage, will output in excess of 20 volts.

Fifth (after making sure the generator belt is on and reasonably tight)
start the engine, rev it up to "a fast RPM" and note the voltage on the
meter.  Twenty plus (20+) volts should be observed.  If reasonably less
than that is observed then proceed as follows:

A.  Remove the generator Back Band (i.e., the cover over the commutator
and brushes).

B.  Using a Commutator Seating Stone (or sand paper/emery cloth will work
- never mind those who say not to do this as I am sure you will use your'
air hose to blow all the grit out anyway) and with the engine running
sand/remove any glaze from the commutator.

C.  Check the spring action in each of the three brush holders by raising
the brush off the commutator and letting it "snap back down" on the
commutator.  If the brush does not snap back down squart something like
WD40 on the brush holder hinge and work it up and down until it does snap.
 Make sure there is enough brush left for the brush (and not the holder)
to make good contact with the commutator.  Check the short wire from the
brush to the generator terminal (e.g., make sure the wire is connected at
both ends).

Now repeat the applicable test steps listed at the top above.  If the
generator still does not pass then I think you will have to see a "good
old time" auto electric man and be ready with $$$ (or try ebay/salvage
yard and try again).

I will add that I tested three generators this Spring and they all failed
the test above but after performing the brush holder/commutator
checking/cleaning they all passed the second time around.

After you get a "known good generator" we can talk about how to check the
regulator.

Good luck - let us know how this all turns out.

Dudley




> Ben,
>
> I've been on a "total vacation" for the past two weeks and just read your'
> post below this morning.  I will respond this evening with the
> instructions -
>
> Dudley
>
>
>> Hello gentlemen,
>>
>> Thank you for your patience with me during the past week or so.  My
>> Grandpa's death was a shock; none of us were expecting it at the time.
>> Now
>> I am needing to get back to getting this Farmall going since it is
>> sitting
>> unable to start where we need to pour concrete!
>>
>> Ted, you mentioned that the incorrect wiring could have caused damage.
>> What type of damage in particular are you thinking is probable?  The
>> motor
>> test I performed was just like you said; the results said the generator
>> is
>> dead.
>>
>> Ted, polarizing the generator is not a basic question.  I didn't even
>> know
>> such a thing existed until a few years ago, and it was the primary issue
>> on
>> the charging problems with my Super A.  That was the first thing I
>> checked.
>>
>> Dudley, you are correct; my generator has 2 studs.  Furthermore, I
>> neglected to explain that my regulator in fact has 4 terminals.  I
>> mentioned only the three lining the front, "L", "Bat" and "Arm".  The
>> one
>> on the back seems to need to be wired to the "F" (field) generator
>> terminal.  I would really appreciate hearing the instructions you
>> mentioned!
>>
>> Thanks to you all for your help,
>> Ben Wagner
>>
>>
>> On Sun, Mar 4, 2012 at 1:10 PM, <drupert at seanet.com> wrote:
>>
>>> Ben,
>>>
>>> Could you tell us a bit more specifics about the Generator & Regulator
>>> that's currently in your' tractor and maybe we could help you (never
>>> mind
>>> for the moment the wiring).
>>>
>>> For example, does the Generator have two terminals?  If so, is one
>>> labeled
>>> "F" or "Field" and is the other the "A" or "Generator" terminal.  And
>>> are
>>> you sure the Regulator only has three terminals and not four?  There
>>> could
>>> be one terminal on the bottom or underneath the Regulator making it
>>> hard
>>> to see.  If your' Generator has the two terminals described above and
>>> the
>>> Regulator four, then it should be easy to check out and we can pass
>>> those
>>> instructions along -
>>>
>>> Dudley
>>>
>>>
>>> > Good afternoon,
>>> >
>>> > I have had a few issues with my 1945 A's electrical system recently,
>>> and
>>> > wanted to bounce a few ideas off the folks on the list.  I will warn
>>> you
>>> > that this email is long and complicated!
>>> >
>>> > The generator was new in the early 90's, according to the previous
>>> owner.
>>> > It was equipped with a regulator (3 connections) which seems to be
>>> > inappropriate for the tractor.  The generator did not work at all,
>>> and
>>> I
>>> > found that it was wired incorrectly. Someone had stacked the "bat"
>>> wire
>>> > onto the far right "arm" wire on the "arm" bracket of the regulator.
>>> The
>>> > load hook up (lights) was on the "bat" terminal.  Would this have
>>> injured
>>> > the generator since it has been run this way probably for years?
>>> >
>>> > After rewiring it, I found that the generator still gives no charge.
>>> I
>>> > measure no voltage from the generator, and the "motor test" also did
>>> not
>>> > give any positive answers.  I believe the regulator is good, but the
>>> > generator itself is not.  I am going to disassemble the generator and
>>> see
>>> > if I can find a problem.  What are the places I should look beyond
>>> loose
>>> > connections, grounded field, and worn brushes?
>>> >
>>> > For reference, what the previous owner did was replace the old
>>> generator
>>> > with a new one.  He rewired it, and replaced the original relay (1
>>> line
>>> > going to the ammeter) with a regulator (2 wires going to the light
>>> switch
>>> > and ammeter).  From the original A electrical parts, only the light
>>> switch
>>> > (4 position) and ammeter remains.  The wiring was updated to match
>>> the
>>> > regulator demands (2 wires) leaving the light switch to hook up
>>> strangely.
>>> >
>>> > Now, I am leaning towards replacing the regulator with a relay to
>>> regain
>>> > originality and to simplify the wiring, but the budget is tight.  If
>>> I
>>> can
>>> > fix the generator, that would be great, but keeping the current
>>> generator
>>> > and regulator would also create the need to really solve this wiring
>>> mess
>>> > for certain.  If anyone has any experience in wiring a regulator to
>>> an
>>> A
>>> 4
>>> > position light switch made for a relay, I would like to hear from
>>> you!
>>> >
>>> > I hope this email made sense.  If you need me to clarify, let me
>>> know.
>>> >
>>> > Thanks in advance for all your help.  My brain seems to not be wired
>>> for
>>> > complicated electrical problems!
>>> >
>>> > Ben Wagner
>>> > _______________________________________________
>>> > AT mailing list
>>> > http://www.antique-tractor.com/mailman/listinfo/at
>>> >
>>>
>>>
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