MTFCA Forum

I understand the procedure for setting the null point, but what happens if the generator is run with the null setting way off?

Here's why I ask... On a recent Speedster tour I noticed my charge rate gradually climbing from about 6 amps to well over 15. Odd... Looking in the generator, it appeared my 3rd brush had moved. No problem, I reached inside to pull it back into position and noticed when I did so, the entire brush necklace rotated. It was then that I saw 2 of the 4 screws holding the necklace in place, had fallen out and the other 2 were about to do so. Not being able to adjust things properly "on the road", I rotated the necklace to what looked "normal", then set the 3rd brush, (which was also loose by the way), and continued the tour, charging about 6 amps. Yesterday, I test drove the car after addressing another issue. During that drive, the charge rate went down to 2 amps and the insides of the generator looked as if they had gotten fairly hot. No smoke or burnt odor however. Naturally, I'll reset the null point, but is it too late now??? Can operating with the null setting way off, or even somewhat off, ruin a generator?

My understanding is that the two main brushes should be set to the magnetic neutral. Consider that as the armature segments rotate past each brush, that the brushes will make contact with more than one segment, thus short circuiting one coil of the armature. So, the brushes are positioned to the magnetic neutral, which is point of least voltage, and therefore least current. This means the least heating and arcing of the brushes.
Essentially, an incorrect null setting causes the generator to run hot and with excess brush current.

Thanks John. Since I've never purposely ignored the setting, I have no idea what being "off" will do, (I assume it can't be good however). It would be like saying "I'm gonna set my connecting rod clearances at .020", just to see what happens."