- Sun Aug 12, 2012 10:54 pm
40-60% efficient? No, brushed motors are 78% efficient and most brushless are 80% efficient. There is very little resistance created by brushes. And when running, the electric passing from the brushes to the commutator actually lessons the resistance because the electrodes are like water molecules and they act as ball bearings. With brushless there is less rotating mass because the magnets do the spinning rather than the armature which is heavier and in brushless it is called the stator. Just like an AC motor. I like converting to brushless with RC plains because the set ups they have in brushless are more powerful than what they have in brushed versions. But you can make a brushed motor just as powerful as any brushless motor. But you can't readily buy them. And the brushless that put out a lot of power for their size get very hot in a short period of time. And when the magnets get hot, they get weak and the brushless motor will slow down and loose a lot of power. And with a brushed motor the heavier part (the armature) does the spinning and since the heavier part does more of the heat disapation, it runs cooler.
Pros and cons go on from there but if you want the most powerful motor set up, you will find they sell them in brushless version today. For RC cars they used to make some pretty insane high performance brushed motors with flat wire on the armature in low turn versions. Run them on a 3cell lipo and they are just as fast a brushless but they made the brushes and commutator too small so you would have to keep changing the brushes and cut the commutator. If they were sufficient in size they would run until the cows came home. No one makes anything like that anymore. Brushless is taking over.