Voltage regulator

Bud said:
Would an 8N tractor voltage regulator work with a Model A Generator?
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I'm gonna try that, I believe the generator on my Model A is from a mid '30s Ford, it has 2 wires coming out of it, one is output, the other goes to ground.

Using the VR that Larryejoh posted a link to.
 
Wouldn’t the 10-12 amp output of the Ford tractor (NAA and later)one I thought of using be more appropriate with the amperage output of a Model A generator than a 35 amp regulator?
 
Larryejoh said:
I would only have to make a new terminal off the field wire which was connected to the 3rd brush to the field on the regulator. The armature wire which went to the cutout would go to the armature/gen terminal on the regulator and the battery wire from the other side of the cutout would go to the battery terminal on the regulator. The field ground would still be grounded to the generator case on a cutout screw.
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I think this would work with a late 1930s or 1940s Ford car regulator. The regulator would be mounted on either side of the firewall. The 3rd brush would be removed from the generator and the wire from the field winding that had been on the 3rd brush would be brought out of the generator case and connected to the field terminal of the regulator. The cutout would be eliminated and the armature wire and battery wire would go to the corresponding terminal on the regulator. Has anyone done this and how did you bring the field wire out of the generator case? Thank you for your comments and suggestions.
 
If you are not concerned about looks, you can just leave the cover off and bring the field wire, normally connected to the third brush, out the slot. If you are concerned about looks, a gutted cutout can be used with a hole drilled in the generator housing and the field wire run up into the cutout can. The two wires can then be routed through the normal conduit or cover to the junction box then run to a hidden regulator. The battery connection at the regulator would have to be run to the normal terminal on the junction box so that the ammeter would work correctly and the electrical systems supplied with current.
 
There is another difference between the 3-brush generators and the 2-brush types that gets over looked. The two brushes, on a generator so equipped, are mounted 180 degrees from each other. The two remaining brushes on a 3-brush unit with the 3rd brush removed are not mounted 180 degrees from each other. I'm not sure how this would affect performance but it might. Keep this in mind if converting.

Most of the pre-1939 V8 generators had the two wires exiting the generator case. This allowed for an optional two stage output control that was available for a time. They were still 3-brush generators that used a cut out but the 2-stage set up would kick in when the lights were turned on to increase the output. The design was intended to prevent overcharging the battery when the lights were off for daytime driving but provide higher output as soon as the lights were switched on. The system could be problematic at times so it eventually fell out of favor. The controller unit's case is more of an oblong shape than the standard round cylinder shaped cut out. Folks just didn't want to mess with the 3rd brush. The 2-brush came along in late 1938 and was fully regulated but they were still a bit limited in output from the 8BA era generators that came out post war. Looking at the 8BA generator's size will explain why it had a higher output than the older small case generators.

The 8N went fully to 2-brush around 1950 when the distributor was also changed. The regulators are marketed as 1950 to 1952 for A type generator circuits that are 10 to 12-amp output. The later tractors had generators with a B type circuit and 10 to 12-amp output. Just make sure you know which way your generator is wired if you seek to use one of these type units.
 
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