Answer / k.prakashchandra

1.A good conductor 2.Can be reshaped easily to suit the
brush holder 3. Chemically inert 4. Does not erode the
commutator segments 5.Does not wear away easily 6.Dust
easily blown away by the cooling air,as being light 7.Not
costly 8. Easily available .(It is used in the form of graphite)

Answer / keepup

as per my limited knowledge i think the reaso y brush is
made of carbon is coz carbon has a negative temperature
coeficient of resistance, that is due to friction between
the brush and rotor, temperature is developed. as a result
the resistance of carbon brushes will decrease. for
instance if copper or aluminum brush is use, then when temp
increases at the contact pt between the brush and rotor,
resistance of the copper or aluminum brush will increase
resulting in loss of energy usually in the form of heat and
may lead to burning of the brushes.

Answer / ahammed

In carbon brushes, since, its like a semicconducting
material, the resistance of which is depends on area of
contact. Its used to reduce sparking & to avoid short
circuit in armature segments.

Answer / saurabh bhardwaj

1.provide high resistance for FORCED COMMUTATION.
2.PROVIDE LUBRICATION BETWEEN COMMUTATOR & BRUSH.
3.LOW COST
4.GREATER STABILITY AT HIGH TEMPERATURE

Answer / niraj

carbon brushes have less friction and thus offer lubrication .

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