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Answer :

The number of brushes in a commutator depends on amount of current to be collected.

Related questions

Last Answer : The material for commutator brushes is generally carbon.

Last Answer : In lap winding, the number of brushes is always same as the number of poles.

Last Answer : The rapid wear of brushes takes place due to abrasion from dust, excessive spring pressure, rough commutator bars, high mica insulation between com-mutation bars.

Last Answer : Armature coil is short circuited by brushes when it lies along neutral axis.

Last Answer : Brushes of D.C. machines are made of carbon.

Last Answer : Copper brushes in D.C. machine are used where low voltage and high currents are involved.

Last Answer : To avoid formation of grooves in the commutator of a D.C. machine the brushes of opposite polarity should track each other.

Last Answer : The insulating material used between the commutator segments is normally mica.

Last Answer : In a commutator mica is harder than copper.

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Last Answer : Number of commutator bars for a 4-pole, 2-layer, DC lap winding with 24 slots and one conductor per layer is 24

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Last Answer : In a DC motor, it is important to place the brushes along Magnetic Neutral Axis

Description : Brushes of DC machine are made up of ?

Last Answer : Brushes of DC machine are made up of carbon.

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Last Answer : In a A.C. series motor armature coils are usually connected to commutator through resistance.

Last Answer : In D.C. generators, the brushes on commutator remain in contact with conductors which lie under interpolar region.

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Last Answer : In case of D.C. machine winding, number of commutator segments is equal to number of armature coils.

Last Answer : The commutator segments are connected to the armature conductors by means of copper lugs.

Description : Etched or burned bands on the contact faces of the brushes in a direct current generator can be caused by ____________. A. high mica segments B. copper drag on the commutator C. brushes improperly positioned D. copper embedded in the brushes

Last Answer : Answer: C

Description : Which of the diagrams shown in the illustration depicts the proper method of aligning brushes on a commutator? EL-0057 A. A B. B C. C D. D

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Description : Brushes in a generator must be positioned in the neutral plane to avoid sparking between the brushes and the _____________. A. yoke B. armature windings C. field pole windings D. commutator

Last Answer : Answer: D

Description : Which of the following is a characteristic of fractional horsepower repulsion start motors? A. They start with a rotating stator field. B. The short circuiting ring is removed from the commutator while ... brushes are removed from the commutator while starting. D. They have a low starting torque.

Last Answer : Answer: B