Why Carbon Brushes are split?

About Carbon Brushes:
1. Carbon Brush	2. Why Carbon is Selected as the medium?
3. Current Density in Carbon Brush	4. Why Carbon Brushes are split?
5. What is Patina?

Generally carbon brushes not used as single blocks. Normally two wafers are bonded with a cushion pad. Three wafers also seen in the industrial sector. Brush sizes and design and grades depends on many criteria and normally is matter of experts.

The splitting is mainly done to increase the contact points. Theories says that the number of contact point does not depend on brush cross sectional area. It is kind of fixed. Normally a carbon block has around 10 contact point regardless with its contact area. So Splitting carbon brushes increase the contact point. If we use two wafer carbon brush then there will almost 20 contact point available.

And also the increased cross resistance due to splitting helps in commutation which is the another good side of brush splitting.