What is the primary difference between AC and DC machines?

• AC machines use alternating current, while DC machines use direct current.

• AC machines are used for high voltage applications, while DC machines are used for low voltage applications.

• AC machines are more efficient than DC machines.

• DC machines are used in power plants, while AC machines are used in household appliances.

Which of the following is a common application of a transformer?

• Converting mechanical energy to electrical energy.

• Changing the voltage level in an electrical circuit.

• Storing electrical energy.

• Generating electricity from solar power.

What is the main function of the commutator in a DC machine?

• To convert AC to DC.

• To reverse the direction of current in the armature windings.

• To increase the speed of the machine.

• To reduce electrical noise.

In a transformer, what is the relationship between the primary and secondary voltages and the number of turns in the coils?

Which type of AC machine is commonly used in household fans?

• Synchronous motor

• Induction motor

• DC motor

• Stepper motor

What is the purpose of laminating the core of a transformer?

• To increase the magnetic field strength.

• To reduce eddy current losses.

• To increase the weight of the transformer.

• To improve the appearance of the transformer.

Which of the following is a characteristic of a DC shunt motor?

• High starting torque

• Constant speed

• Variable speed

• Low efficiency

What is the typical efficiency range of a transformer?

• 50% to 60%

• 60% to 70%

• 70% to 80%

• 95% to 99%

Which of the following is NOT a type of transformer?

• Step-up transformer

• Step-down transformer

• Isolation transformer

• Rotating transformer

What is the unit of measurement for the power rating of a transformer?

• Watts

• Volts

• Amperes

• Kilovolt-amperes (kVA)