M38A1 Charging Problems

1952 - 1968, M38A1, M170, questions, discussions, regarding anything related to the M38a1 series.
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jhawkins64

M38A1 Charging Problems

Post by jhawkins64 » Tue Jul 01, 2003 5:03 pm

I have a 53 M38A1 that I can't get to charge even after changing to a good voltage regulator, a different generator(24V known to work< and checking a cleaning all ground straps on the voltage reg and gen and still it won't charge. Any ideas what I might try now. I haven't tried a different cable hook up yet.
Thanks. Jack


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Glen
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Post by Glen » Fri Jul 04, 2003 1:43 am

If the jeep runs and all the other electrical items work, then the ammeter is working. Even though you have installed a known good generator, you still need to polarize it. Disconnect the cable running between the Generator and Regulator. Note where the index tab is located (where the slot on the plug of the cable lines up) on the top of the elbow on the Generator. There are three female terminals in the elbow; you want the lower left terminal when looking in to the elbow. This is the FIELD terminal. Connect a wire to this terminal and quickly brush the other end on the hot terminal on the starter one time. The generator is now polarized.

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Post by Guest » Fri Jul 04, 2003 5:45 pm

Glen
Thanks for the reply, will give it a try and post for all to read. Thanks again
Jack

Guest

Post by Guest » Mon Jul 07, 2003 10:13 am

Glen
WEll I did the polarizing trick and it is charging now, thanks for you input. The only thing now is that on occasion it will charge from 24.4 Volts to as high as 27.8. Sounds like a voltage regulator problem to me so will have to take a look at that. At leas t it is charging now. Thanks again
Jack

John L. Smith

charging

Post by John L. Smith » Mon Jul 07, 2003 11:53 am

Don't touch it, it works.....27.5 vdc is good, and normal....Check your manual, Battery voltage will be around 24.5 and charging voltage will be around 27.5....

John L. Smith
AMVCC
MVPA 19010
m37
m880
m101
Prius.....that's another story

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Post by Guest » Tue Jul 08, 2003 5:38 am

John
Appreciate the input and will leave it as is, I am glad to have that probelem behind me, now I can move on to a different one. Thanks again
Jack

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Felix
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Post by Felix » Tue Jul 08, 2003 11:28 am

I just adjusted my voltage regulator last Sunday following the instructions that Wes K sent me, by the way, thanks Wes.
Instructions by Wes K:
"You'll need a copy of TM9-1825B Electrical Equipment (Auto-Lite) November 1952 or newer. Or TM9-1825A or C (can't remember) Electrical
Equipment (Delco Remy). If you have the Auto-Lite VBC4002UT or VBC4003UT look at the regulator from the side with the 2 electrical plugs to your left, the 3 major units are left to right: 1-Circuit breaker 2-Current regulator 3-voltage regulator. Usually problems are just pitted
or corroded contacks. File them very lightly with a ignition point metal file (or a girl's METAL finger nail file) then clean them by
passing a tape of thin cloth soaked in carbon tetrachloride or any top quality electric contact cleaner.Run her and see what you get.
Adjustment is straight forward for each. Circuit breaker armature air gap .000 to .065 and contact point gap .035 min. Current regulator
armature air gap .047 to .049 and gap between contact spring and stop is .010 to .016. Voltage regulator armature air gap is .040 to .042
and gap between contact spring and stop is .010 to .016. Contact pressure for CR & VR is 7 to 8 OZ's. Circuit breaker operatin ranges are
closing volts 25.7 to 26.7 and opening amps (discharge) 7.0 to 11.0. Current regulator operating amps 24.5 to 26.0. Voltage regulator
operating voltage at 70 Deg's is 28.30 + or - .40."
Felix (LtCol "Ground Spook")


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