Cell Specific Information On Brushes For RC Cars
Commutator is also known as 'com' for short. It is the part of the rotor (the part inside which turns) which has three copper contact for the brushes to run on. It should be kept clean and skimmed regularly for optimal efficiency and motor life. Brushes are the two copper contacts that supply power to the commutator of the motor. These should be replaced regularly for optimal efficiency and motor life.
Brushes is the area where people differ GREATLY in opinion of which brush to use, to cut or not to cut, timing or no timing etc. One should get an idea about what works for his model and what does not. Some tips for the brushes should be taken care of.
In 1/12th scale stock, you do not want to run a full brush. It has been found that it is best to cut about 10% off the trailing edge of the brush. This tends to give a little more RPM. Also, a little experimenting reveals that with drilling the center of what is remaining (small hole) to decrease surface contact area, thereby reducing friction (theoretically anyway) and gaining a bit of efficiency.
Also it should be noted that efficiency is gained by removing material from the top of one brush and the bottom of the other. This allows the com to wear evenly and again reduces contact area without affecting timing.
It is a matter of personal choice as to which brushes to start with. However, brushes with higher silver content make the most power and consequently are the hardest on the comm. This means more maintenance on a regular basis and more frequent visits to the lathe.
One can have his own individual preference to go for . Like someone may be partial to the EastCoast R-29 brush and the Trinity 4070. He may have had good success with both of these brushes and actually prefer the R-29 to the 4070, but each has its benefits and drawbacks. Other can try out their own choices and experiment with them.
6-cell specific is an entirely (almost) different critter. When doing motors for RS-4 that one basically needs to put a slightly stiffer spring on BOTH sides of the motor to get the best results. Using a slightly softer spring on the '-' helps to gain a little more RPM and gain in efficiency.
Efficiency is not as important in 6-cell racing as all out power since one is only racing 4 minutes. One normally has almost two minutes left after a four minute race in 4WD using batteries in the 360 second range.
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