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Bob C · 09-05-2016, 05:25 PM

This might help explain how your generator works.

THREE BRUSH GENERATOR OPERATION:
The three brush generator design required removing the cover and adjusting the position of the third brush in order to change the charging rate.By moving the position of the third brush the voltage applied to the field windings was changed. This in turn changed the strength of the magnetic field applied to the rotating armature and thus set (or limited) the maximum charging rate, or current output, of the generator. The generator would continue to charge at this fixed current rate all the time, regardless if the battery was boiling over or dead, lights on or off, it didn’t matter. This was fine if the electrical load on the system remained constant, but loads usually do not. If the battery was low, or additional loads such as lights were turned on, the generator output remained the same. In short, the 3 brush generator cannot automatically compensate for any type of varying electrical loads.
The 3 brush generator did not have any type of voltage regulator built into it. Adjusting the 3rd brush only changed the current output of the generator. The battery essentially became the voltage regulator in the system. As a result, the generator consistently applied an excessively high voltage to the battery (on the order of 8 – 8.5 volts). In fact, as the battery reached a fully charged state, the generator current output actually increased slightly as did the battery voltage! Over prolonged periods, this would cause overcharging of the battery. Many batteries and fine paint jobs have suffered from this poor regulating system!
If for some reason the battery were to be dropped out of the circuit, the generator output voltage would now be unregulated. If allowed to run unregulated, the generator voltage would quickly rise and could easily get up to 40 or 50 volts. This would in turn burn out the light bulbs and other electrical equipment, such as ignition coils. Excessive heat would be generated internally and quickly damaged the generator as well.

Bob

09-05-2016, 05:25 PM	#43
Bob C Senior Member Join Date: May 2010 Location: So Cal Posts: 8,755	Re: Generator Third brush Adjustment This might help explain how your generator works. THREE BRUSH GENERATOR OPERATION: The three brush generator design required removing the cover and adjusting the position of the third brush in order to change the charging rate.By moving the position of the third brush the voltage applied to the field windings was changed. This in turn changed the strength of the magnetic field applied to the rotating armature and thus set (or limited) the maximum charging rate, or current output, of the generator. The generator would continue to charge at this fixed current rate all the time, regardless if the battery was boiling over or dead, lights on or off, it didn’t matter. This was fine if the electrical load on the system remained constant, but loads usually do not. If the battery was low, or additional loads such as lights were turned on, the generator output remained the same. In short, the 3 brush generator cannot automatically compensate for any type of varying electrical loads. The 3 brush generator did not have any type of voltage regulator built into it. Adjusting the 3rd brush only changed the current output of the generator. The battery essentially became the voltage regulator in the system. As a result, the generator consistently applied an excessively high voltage to the battery (on the order of 8 – 8.5 volts). In fact, as the battery reached a fully charged state, the generator current output actually increased slightly as did the battery voltage! Over prolonged periods, this would cause overcharging of the battery. Many batteries and fine paint jobs have suffered from this poor regulating system! If for some reason the battery were to be dropped out of the circuit, the generator output voltage would now be unregulated. If allowed to run unregulated, the generator voltage would quickly rise and could easily get up to 40 or 50 volts. This would in turn burn out the light bulbs and other electrical equipment, such as ignition coils. Excessive heat would be generated internally and quickly damaged the generator as well. Bob