In a commutator mica is harder than copper.
Answer : To avoid formation of grooves in the commutator of a D.C. machine the brushes of opposite polarity should track each other.
Answer : The number of brushes in a commutator depends on amount of current to be collected.
Answer : The insulating material used between the commutator segments is normally mica.
Answer : The material for commutator brushes is generally carbon.
Description : State the function of commutator in DC generator and name the material used for commutator.
Answer : Function of Commutator: Commutator converts AC induced in armature winding into DC for external load. Material: i) Commutator segments are made up of Copper. ii) Commutator segments are insulated from each other by Mica.