alt Hacker NewsIt's interesting that this is a brushed design. In the RC car community, brushless motors are generally regarded as superior, but those of course have the rare earth magnet problem.
Technically the brushes can wear out, although there are claims they are good for 150,000-250,000 miles it seems.
It's technically not a brush but a slip-ring. The design of these motors is very similar to automotive alternators, just scaled up 100x (in terms of power).