Motor and Motor Control Circuits Week 3 Coursera Quiz Answers

Motor and Motor Control Circuits Week 3 Coursera Quiz Answers

1. What causes a motor to generate back emf?

The armature windings rotate through the magnetic field created by the field windings. They then become a generator, creating a current in the opposite direction to the applied current

2. What is the power in horsepower of a DC motor operating at 1000 RPM and 2 lb-ft torque? (Type in a two-decimal number.)

0.38

3. Which of the following are causes of energy loss in a DC motor? Select all that apply.

Current flow in the armature and field windings

Magnetic hysteresis in the iron core

Eddy current losses in the field windings

4. What is true about the speed of a shunt wound DC motor? Select all that apply.

The speed is proportional to the square of the armature resistance

The speed is inversely proportional to the magnetic flux

6. What is true about a permanent magnet DC motor?

Items (1), (2), and (4)

7. Where might the motor control circuitry be located in a servomotor?

In a separate control box from the motor housing

In the same box as the motor housing, but packaged separately from the field windings

8. What is true about a brushless DC motor?

The stator coils are turned on and off at precise times to make it rotate

9. What is the function of the commutator circuit board in the permanent magnet motor shown in the video titled "Paper Shredder Teardown"?

It switches the direction of the current to the armature windings

Comment below the answers to 5 and 10