AET630 -Introduction to Electrical Machines -Quiz 2

Which of the following is NOT a type of DC motor?

• Series motor

• Shunt motor

• Synchronous motor

• Compound motor

The speed of a DC motor can be controlled by varying:

• Voltage applied to the armature

• Voltage applied to the field

• Both a) and b)

• None of the above

In a DC motor, the stator is:

• Stationary

• Rotating

• Both a) and b)

• None of the above

The commutator of a DC motor is used to:

• Switch the direction of current in the armature

• Generate a magnetic field in the rotor

• Control the speed of the motor

• None of the above

Which type of DC motor has a high starting torque?

• Shunt motor

• Series motor

• Compound motor

• Both b) and c)

The function of brushes in a DC motor is to:

• Switch the direction of current in the armature

• Generate a magnetic field in the rotor

• Conduct current to the armature

• None of the above

A compound DC motor has:

• A series winding and a shunt winding connected in parallel

• A series winding and a shunt winding connected in series

• A permanent magnet instead of a field winding

• None of the above

The efficiency of a DC motor is given by:

• Output power/input power x 100%

• Input power/output power x 100%

• Input power x output power

• None of the above

Which type of DC motor is commonly used in machine tools and fans?

• Shunt motor

• Series motor

• Compound motor

• None of the above

The torque of a DC motor is proportional to:

• Voltage applied to the armature

• Current flowing through the armature

• Both a) and b)

• None of the above