Design of brushes and Commutator

What is the main purpose of the commutator in a DC motor?

• a) To reverse the direction of current flow

• b) To regulate the speed of the motor

• c) To generate an electromagnetic field

• d) To prevent the motor from overheating

What material is commonly used to make the commutator?

• a) Copper

• b) Silver

• c) Gold

• d) Platinum

What is the purpose of the brushes in a DC motor?

• a) To supply current to the commutator

• b) To regulate the speed of the motor

• c) To generate an electromagnetic field

• d) To prevent the motor from overheating

What material is commonly used to make the brushes?

• a) Copper

• b) Silver

• c) Graphite

• d) Platinum

What is the primary reason for using multiple brushes in a DC motor?

• a) To increase the speed of the motor

• b) To improve the electrical conductivity

• c) To reduce friction on the commutator

• d) To reduce the amount of heat generated

What is the purpose of the brush spring in a DC motor?

• a) To hold the brush in place

• b) To provide electrical insulation

• c) To increase the conductivity of the brush

• d) To reduce the amount of heat generated

What is the purpose of the commutator in a DC generator?

• a) To reverse the direction of current flow

• b) To regulate the voltage of the generator

• c) To generate an electromagnetic field

• d) To prevent the generator from overheating

Which type of commutator is used in AC motors?

• a) Segmental commutator

• b) Hooked commutator

• c) Ring commutator

• d) Multi-layer commutator