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maok

'37 Dodge generator/regulator issue

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Hi guys, you may have seen my new '37 Dodge that I recently acquired, which I took delivery mid week.

 

The previous owner installed a kenwood 12v stereo in, you can see its not a perfect match, not the greatest wiring job but looked okay. A 6v to 12v stepup transformer was also installed because the car is still 6v +ve ground and a noise suppressor module. The missus said, "has to go" which I didn't disagreed with, so I pull it out.

 

Now the ammeter reads full charge (actually, well pass the 20amp reading) as soon as I put my foot on the throttle, even the slightest push. At idle the ammeter needle is at 0. I haven't dug into it yet, but what could make the generator/regulator do this. The only thing I can think of is that the battery is not holding its charge, however, it does turn over and start the car easily, this implies the battery is not bad. Before I removed it, the ammeter was reading correctly. Its got me puzzled.

 

Any suggestions?

 

IMAG2909.jpg.1d71289274d5a11ee74d4b082643dfcb.jpgJCM4040710-1.jpg.d5d497e7ab5578e72eff791b4baea185.jpg

 

 

Edited by maok

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 Some of the early mopars didn't have a separate voltage regulator , instead there was a third brush in the generator that was adjustable and controlled output . If you have an shop manual for your vehicle this procedure would be included in the text . As to why it acts up now that the radio is out ... i don't have a clue . Perhaps more voltage was required for the radio transformer . 

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Thanks Jerry, it's a full voltage and current regulated setup. My '28 has the simple three brush and cutout setup.

 

After digging out all the wiring that was installed for the radio/setup module and noise suppressor, there nothing relating to the generator or regulator..  Lol

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Don't have any brilliant answers but I would go back and check all the connections that were disturbed in the course of removing the radio and module. Last things touched would be prime suspects...  :)

Edited by Sam Buchanan

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Is your voltage regulator ok? Somewhere in this forum I & others have

posted a wiring diagram, mine from a later but similar MOPAR.

Make sure all your connections are right & don't start a fire . You're

putting a lot of voltage through your system. 

Speaking of fire, hope you Oz guys get the fires under control

soon We all wish your country the best with that awful situation.

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Thanks for the replies.

 

At idle, it is charging the battery without any accessories on, I confirmed by attaching a voltmeter on the battery and watched the voltage rise from about 6.4v to 6.9v. At full charge rate, it reads about 7.4v.  When the head lights are switch on at idle, the ammeter reads a discharge, so the ammeter is functioning correctly. Fast idle or anything well above idle the ammeter immediately goes off the scale to +20amp.

 

I have eliminated all the wiring from the  radio, 6v to 12 v step up transformer, there was also a cigarette lighter socket installed under the dash, but with no obvious signs of any issues. It also looked like there was a provision to run the 12 volts accessories from a 12 volt battery under the drivers seat (RHD).

 

I pulled the regulator cover off to find an interesting mod, the cut out relay has been replaced by two diodes in parallel. Either looked more than capable to do the job on its own. So, Im not sure why 2 were installed.

IMAG2921.jpg.a5c5862b958bad83915cd4f5169dfa1c.jpgIMAG2919.jpg.3c24533f05798b4fafc2a10a71252cc7.jpg

 

Both the voltage and amp relays look okay to me, but I have never serviced one. The amp relay ( the centre unit) does not seem to cut out when the engine is revved up.

Edited by maok

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At idle is when a generator is at it's least capable.  You realize the cut out relay and all of the relays are adjustable? 

 

Not sure I like the diode setup, no idea what they were trying to do with it.  Thinking on it and seeing what it replaced, it looks like those diode are just telling the generator to always charge since they replaced the voltage regulator relay.

 

 

 

Attached are the adjustment procedures out of my 37 Plymouth service manual.

 

 

 

 

VR 1.JPG

VR2.JPG

VR3.JPG

Edited by Sniper
added specifications table

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Thanks for the specs pic, much appreciated.

 

The diode mod is there to replace the cutout relay, its a common mod for the more simple 3 brush generator/cutout relay combinations.

The diodes allow one direction of current flow ie, to the battery only.

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The cut out is supposed to assess battery charge level and cut out the Gen when the battery is at full charge in later setups,. Not sure with the older three brush deals.  Either way feeding current to a fully charged battery is unnecessary and could be harmful to the battery and the Gen.

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   My P-15 manual has a "ammeter shows high charge" heading. It seems that your field coils are grounded. Testing will tell if it's the generator or the regulator. Because it started on a stereo removal, I'd add engine to firewall, firewall to fenders, and engine to frame, grounds. I've read of some stereo installs, isolating body parts.  Maybe the regulator lost it's ground, when you removed the voltage converter. 

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Maok is correct, the Zener Diodes replaces cut off relay. No overcharging or direct battery connection due to voltage coil. Diodes are faster and more precise.

 

But photo shows a 3 "coil" regulator for a modern 2 brush generator. (voltage, current and cut off)

A typical 3 brush generator only has 2 coil regulator. (current and cut off)

 

It's simple to convert a 3 brush generator to a 2 brush generator for more reliable charging. Maybe this has been done to your generator.

Edited by chrysler1941

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Thanks guys for the input.

 

I have done all the basics, with no luck. Cleaned all the terminals on the generator and regulator, cleaned both the current and voltage  relay points in the regulator. Checked the generator by motoring it ( fan belt not attached). So I am stumped.

 

Next is to get under the dash and look for a short where the radio may have been connected.

 

A 6volt alternator is on its way from the land of the free.

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the only thing i feel sure of- it couldn't hurt1

 

dj

Edited by DJ194950

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Well it worked...:) Moral of the story is, check your battery if you are having charging issues.

 

I've used it before on old batteries that have been sitting around for a while.

 

IMAG2936.jpg.7fe03d80107789312d34d85b5c95d0b3.jpg

 

 

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Good catch, I think we all got spoiled by maintenance free batteries.  Might be a good idea for all of use to add "check the battery water" to our maintenance checklists.  I believe ht emanual calls for distilled water, which you can buy at the store, or "chemically pure" water.

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