This is not a tutorial or training session on the operation of a 12v three brush generator, but there is some discussion using the cover of poetic license. I do not want to suggest my observations in the video are 100% correct by any means, and is at best a cliff notes version of possibly improper diagnostics. For your system, I would suggest searching a site that specializes in automotive or tractormotive charging systems. But this one is fun anyway.
There are plenty of reasons to convert an old tractor to a 12 volt alternator system.... Especially if it had been converted at an earlier time from the original 6 volt generator. I do not do restoration work on my tractors, I get them mechanically in condition to use them on a daily basis if necessary. If I were to 'restore' tractors and 'restore' being a relative term I would possibly consider going back to all original. The wiring on this tractor is mostly original from 1945 and is very brittle and cracked. It has to be rewired already, so we will eliminate all the confusion in the ignition and charging circuit by extremely simplifying the system.
However, I do usually insist on testing the existing system no matter what it is and if it is found to be in good working order, it is left in place. Not a problem. Well on this one there's a cliff notes and not totally accurate description of the generator, its operation, adjustment and output limiting circuit. Let me be clear....I am NOT proficient in the repair or trouble shooting of the generator circuits by any means, knowing only a bit more than a chimp in the closest zoo. (I think). That being said, I do give a rundown of basically how the light switch/resistor/cutout circuit works in this system but do not take that info to the bank. A 'cutout' seems to do basically the same thing as a regulator. They both contain a relay to open and close to maintain charge in the battery, but do it in entirely different manners and usually are found on two different types of generators. Three brush for the cutout and two brush for the voltage regulator. Both are slightly adjustable.
So after a basic test, I find the cutout is definitely not doing its job, having been disconnected many years before the tractor came to live with me. I kind of suspect that this system failure is what forced the old timer to park this thing so many years ago. Soooo the generator is in fact working but its working too good....its putting out about 20v and I cannot get the output to reduce by moving the third and moveable brush on the armature. To further test, a replacement cutout needs to be purchased so that'd be another twenty bucks going into just testing with no guarantee it would remedy the problem. The problem could be in the light switch/resistor portion of the circuit. Ultimately the decision to eliminate the confusion as well as the weather cracked wiring was made to go ahead with the simple one wire alternator conversion....self excited and internally regulated, its quick, simple and reliable for years to come.
The best part of this video...because there IS a lot of talking....is the nice single post heavy duty adjustable bracket formed to support the fancy new alternator. A standard Delco 10SI or 12SI alternator housing is much too large to fit within the confines of the allotted space so a smaller one had to be located. This one is only 3 7/8" in diameter and will not require alteration to the sheet metal shroud like the 5 1/2'' Delco counterpart.
Disclaimers have been numerous, so don't bother trolling the video with negative comments but please feel free instead to help my viewers and myself as well with positive information of facts that are not portrayed accurately.