Voltage Regulator Case SC

I have a VRP-4104A Autolite regulator (voltage regulator and cutout) on the GHD 6001010 6V (NEG. ground) generator which is installed on my 1954 Case SC tractor (mag ignition). Both are original to the tractor. I just took the generator in to a shop to replace a bad bearing. They reconditioned everything in the generator including turning the commutator, replacing the brush holders, and replacing the brushes with a NOS set that I found cheap a few years ago. The cutout works properly, but the VR was stuck on full charge (~20 amps).
Everything looks good under the regulator's cover (points are clean, and no corrosion), but the VR is not like anything that I have been able to find in any of the free Autolite manuals that I have found online. It has the moving point connected to the adjustable stop, not connected to the armature (which is sprung). Thus, I used a process of trial and error to determine the proper contact gap on the VR (by decreasing the gap in 0.005" increments, starting at 0.040", until it charged about right). It is now set at 0.020", and the generator outputs 8.35 V when connected to my fairly new 6V battery.
Does anyone have a newer manual (than 1952) which details the armature gap and voltage numbers for this VR? Also, it charges the battery at about 11A continuously and at about 2A with all of the lights (original type and correct CP bulbs) on and the engine at high throttle. It seems like I could and should decrease the output voltage so that it doesn't overcharge the battery when the lights are off. Also, the amp meter needle oscillates up and down about 2 amps when the lights aren't on and the VR is regulating, rather than holding steady like the one on my Case VAC. I assume that this should not be happening, and that I still need to do some adjusting.
 
You have left out a VERY important piece of info... What is the charging VOLTAGE... and is is constant/regulated or does it keep increasing and heating/boiling the batteries more and more the longer then engine runs?
 
The charging voltage is about 8.35V and it is regulating. I checked the voltage slightly above idle with the lights off. When I run the throttle up to full speed, the charging amperage decreases by about one amp and the amp gage needle is more steady. When I lower the rpm back to idle, the (average) charge rate increases by about 1 amp, and the needle oscillates like before. I have tried this over a dozen times and I still get the same results. I plan to go back out tonight to tweak the contact gap up to 0.025" to see if I can get closer to a 7.4V charging output. I haven't touched the armature spring yet, as I need to make sure the point and armature gap are correct before I try to adjust the voltage with the spring (also, I am hoping that no one else has messed with the spring, and that I can get the regulator working correctly without messing with it).
 
Remember something from back in high school shop class about the resistors on the bottom of the regulator are there to prevent the oscillating voltage? Theory is the resistor never lets the gen drop completely out of circuit so it maintains a small charge rate even when the contacts are open. Something to check...
 
(quoted from post at 18:00:38 06/18/15) Remember something from back in high school shop class about the resistors on the bottom of the regulator are there to prevent the oscillating voltage? Theory is the resistor never lets the gen drop completely out of circuit so it maintains a small charge rate even when the contacts are open. Something to check...
teve, it does keep a small field current present, but I contend that the "primary" reason for the resistor(s) is arc suppression across the VR contacts.
 
Does your generator have a third brush? If so adjusting the 3rd brush closer to the other brush will increase the generator output.

The way you're describing the 1 amp charge and the gauge jiggling around seems to tell me that you have the field current going thru your amp meter and not your armature current going thru the amp meter.

The resistors on the bottom of the regulator are for current to pass thru from the field windings. The stronger the field current the higher the charge rate will be. The resistor is used to cut this current down. Between the points and the resistor current is constantly flowing thru both of them as the points in the regulator buzz. The more the battery charges the more current flows thru the resistor to cut down the charge rate.
 
Thank you for your advice. I decreased the armature gap to the value given in the manual for the old style VR (0.050", and the contact gap is now 0.017"), and the oscillation went away everywhere except when the lights were off and the battery was floating at full charge. Also, the oscillation decreased to about +/- 0.5 amp and a frequency of about 2 cycles/second. After making the adjustment to the VR armature gap, I bent the spring holder up to decrease the voltage to 7.4 V when hot and when the battery is fully charged. Interestingly the charging system now makes 7.30 volts at full throttle, 7.4 volts at mid-throttle, and 7.45 volts at idle at 500 rpm. It even charges at 1 amp with all of the lights on at idle. I have never had a generator work this well, but am still a little apprehensive about the oscillation.
 

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