Answer / rajeshsan

Brushes with metal will lead arc and more wear & tear, Hence for large rating we will use carbon brushes. And for toy motor and very small motor use metal brushes.

Answer / mohanavel.u ,marg ltd

The carbon brushes are having the self lubricating capacity
and if metal is used it will lead to more wear and tear
produces spark and damage the armature.

Answer / pavan msh

brushes used in dc machines are mostly made of carbon bcz carbon is of low cost and also a good conductor

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Hi all I had applied for the RRB test in the ELECRICAL category. I would be pleased if any of you can sent me previous year question papers. Please forward the question papers to varshashahi@yahoo.com Thanks and regards Varsha

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