Why do we use carbon brush in dc generator instead of copper brush?

@Kaustubh Katdare • 09 Feb, 2009 [Thread moved to Electrical Engineering Section]

@Ashraf HZ • 09 Feb, 2009 I believe nowadays the brushes is a mix of both carbon and a bit of copper. The issue is to seek balance between the abrasion of the commutator and the wearing of the brushes.

But, looking at the extreme end of things, a full copper brush will cause great abrasion of the commutator. Add carbon, you'll maintain the longer life of the commutator, but the brushes themselves would wear out over time.

@Rifaa • 09 Feb, 2009

ash

I believe nowadays the brushes is a mix of both carbon and a bit of copper. The issue is to seek balance between the abrasion of the commutator and the wearing of the brushes.

But, looking at the extreme end of things, a full copper brush will cause great abrasion of the commutator. Add carbon, you'll maintain the longer life of the commutator, but the brushes themselves would wear out over time.

Could not have said any better.
Mainly because of carbon last longer when they grind with copper, and it's soft and has a lower resistance.
If u think of touching any thing harder than copper in the commutator, do you it will last even a minute. 😲 I think not.