DEA construction of DC machine

What is the core material used in DC machines?

• a) Iron

• b) Copper

• c) Aluminum

• d) Silver

In DC machines, what is the function of commutator?

• a) To convert AC to DC

• b) To provide electrical insulation

• c) To change the direction of current

• d) To switch on and off the machine

Which type of winding is used in the armature of a DC machine?

• a) Lap winding

• b) Wave winding

• c) Progressive winding

• d) Concentric winding

What is the purpose of the field winding in a DC machine?

• a) To produce the magnetic field

• b) To provide electrical insulation

• c) To increase the speed of the machine

• d) To convert AC to DC

What is the function of brushes in a DC machine?

• a) To provide electrical insulation

• b) To support the armature

• c) To connect the armature to the power supply

• d) To transfer electrical energy from the power supply to the armature

Which of the following is an advantage of a DC machine over an AC machine?

• a) DC machines are cheaper

• b) DC machines are more efficient

• c) DC machines produce less noise

• d) DC machines require less maintenance

In a DC motor, which part converts electrical energy to mechanical energy?

• a) Field winding

• b) Armature

• c) Commutator

• d) Brushes

What is the purpose of interpoles in a DC machine?

• a) To reduce the sparking at the brushes

• b) To increase the magnetic field strength

• c) To improve the commutation

• d) To reduce the noise of the machine

In a DC machine, which type of winding is used in the field poles?

• a) Lap winding

• b) Wave winding

• c) Progressive winding

• d) Concentric winding

Which type of DC motor provides a constant speed?

• a) Series motor

• b) Shunt motor

• c) Compound motor

• d) Universal motor