The alternator I was trying to fit before was a great match eletrically, but was just a little too big. I ended up switching to a small alternator. This units fits great, but it is internally regulated. The automative internally regulated alternator don't have a function for overvoltage protection. After researching the alternative I decided to conver it to externally regulated.
To make the conversion I basically gutted the regulator removing all the internals and adding some jumpers to connect the brushes to the external connector. I had to modify the brush holder also. The regulator in this unit regulates on the negative (low) side of the field, while the external regulator uses the positive (high) side with a common ground. Unfortunately, the brush holder support is also a direct connection to the the alternator output. I had to bypass that connection and wire the brush separately.
