Master Advanced Electric Motors: Online Quizzes for Electrical Engineering MEng Students

Question 1

What is the defining feature of a stepper motor?

Accepted Answer

Converts electrical energy into rotational motion in discrete steps

Answer

Used in applications requiring high speed and torque

Answer

Employs a permanent magnet rotor and a stator with wound coils

Answer

Has a high efficiency and low maintenance requirement

Question 2

Select the major advantage of using a servo motor:

Accepted Answer

Precise speed and position control

Answer

High torque at low speeds

Answer

Wide speed range

Answer

Low maintenance requirement

Question 3

Which parameter is NOT used to evaluate the performance of a special electrical machine?

Accepted Answer

Acceleration

Answer

Torque

Answer

Speed

Answer

Efficiency

Question 4

What is the primary role of a resolver in a servo motor?

Accepted Answer

Measuring the angular position of the rotor

Answer

Controlling the speed of the motor

Answer

Amplifying the motor current

Answer

Providing feedback to the controller

Question 5

What is the purpose of employing a feedback loop in a servo motor control system?

Accepted Answer

Enabling closed-loop control of the motor

Answer

Providing real-time data on the motor's performance

Answer

Increasing the motor's efficiency

Answer

Reducing the motor's noise

Question 6

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

Accepted Answer

Stepper servo motor

Answer

DC servo motor

Answer

AC servo motor

Answer

Hydraulic servo motor

Question 7

What is the key difference between a wound-field synchronous machine and a permanent magnet synchronous machine?

Accepted Answer

Type of field excitation

Answer

Rotor construction

Answer

Efficiency

Answer

Power factor

Question 8

Which fundamental difference distinguishes a stepper motor from a servo motor?

Accepted Answer

Closed-loop control system in servo motors

Answer

Lower torque output in stepper motors

Answer

Higher efficiency in stepper motors

Answer

Smaller size of stepper motors

Question 9

What is the primary advantage of employing a micro-stepping driver for a stepper motor?

Accepted Answer

Increased positioning accuracy

Answer

Enhanced torque output

Answer

Improved speed regulation

Answer

Reduced noise and vibration

Question 10

Which characteristic is NOT associated with a synchronous reluctance motor?

Accepted Answer

Presence of permanent magnets

Answer

High efficiency

Answer

Low noise

Answer

Self-starting capability

Question 11

What is the typical control algorithm used in servo motor systems?

Accepted Answer

PID controller

Answer

State-space controller

Answer

Fuzzy logic controller

Answer

Neural network controller

Question 12

Which industry sector is a major application area for stepper motors?

Accepted Answer

Industrial automation

Answer

Medical imaging

Answer

Consumer electronics

Answer

Electric vehicles

Question 13

What primarily determines the efficiency of a brushless DC motor?

Accepted Answer

A combination of core and copper losses

Answer

Core losses

Answer

Copper losses

Answer

Mechanical losses

Question 14

What is the primary advantage of utilizing a resolver for position sensing in a servo motor system?

Accepted Answer

Absolute position measurement

Answer

High accuracy

Answer

Low cost

Answer

Resistance to noise

Question 15

Which of the following advanced electric motors is NOT covered in this unit?

Accepted Answer

Induction motor

Answer

Stepper motor

Answer

Servo motor

Answer

Brushless DC motor

Question 16

Stepper motors primarily operate on the principle of:

Accepted Answer

Magnetic reluctance

Answer

Electromagnetic induction

Answer

Piezoelectric effect

Answer

Hall effect

Question 17

A significant advantage of servo motors lies in:

Accepted Answer

Closed-loop control

Answer

High torque-to-weight ratio

Answer

Low cost

Answer

Simple construction

Question 18

Commutation in brushless DC motors is achieved through the use of:

Accepted Answer

Electronic sensors and controllers

Answer

Mechanical brushes

Answer

Permanent magnets

Answer

Diodes

Question 19

The superior efficiency of brushless DC motors compared to brushed DC motors is primarily due to:

Accepted Answer

Reduced mechanical losses resulting from the absence of brushes

Answer

Enhanced magnetic field concentration

Answer

Use of higher gauge wire for armature windings

Answer

Operation at higher speeds

Question 20

Which of the following is outside the scope of this unit on special electrical machines?

Accepted Answer

Induction motors

Answer

Servo motors

Answer

Brushless DC motors

Answer

Stepper motors

Question 21

Stepper motors operate on the principle of:

Accepted Answer

Electromagnetic interaction between stator and rotor teeth

Answer

Faraday's law of electromagnetic induction

Answer

Lorentz force

Question 22

Brushless DC motors offer a key advantage over brushed DC motors. What is it?

Accepted Answer

Reduced maintenance due to the elimination of mechanical commutation

Answer

Lower cost

Answer

Higher torque density

Question 23

In a servo motor control system, the purpose of a tachometer is to:

Accepted Answer

Measure motor speed

Answer

Provide position feedback

Answer

Control motor torque

Answer

Improve motor efficiency

Question 24

What is the fundamental difference between a stepper motor and a servo motor?

Accepted Answer

Stepper motors operate in discrete steps, while servo motors provide continuous rotation

Answer

Stepper motors require more power than servo motors

Answer

Stepper motors are less precise than servo motors

Question 25

When selecting a special electrical machine, which of the following factors is irrelevant?

Accepted Answer

Brand loyalty

Answer

Application requirements

Answer

Cost

Question 26

In a brushless DC motor control system, what is the role of a resolver?

Accepted Answer

Provide position and speed feedback

Answer

Control motor torque

Answer

Improve motor efficiency

Answer

Reduce motor noise