Aux 2 Unit 5 Quiz 4

Aux 2 Unit 5 Q4

1 / 8

What is the primary function of Pulse Width Modulation (PWM) in AC induction motor speed control?

A) To change the physical size of the motor

C) To permanently increase the motor’s output power

B) To vary the frequency and voltage applied to the motor for speed control

D) To reverse the direction of the motor

2 / 8

What is one potential drawback of using PWM for motor control?

B) Increased torque at low speeds

D) Reduced lifespan of the motor

A) Increased energy consumption

C) Generation of electrical noise that may require filtering

3 / 8

What is the “duty cycle” in the context of PWM?

B) The ratio of the time the signal is on to the total period of the cycle

D) The frequency of the AC supply

C) The total power supplied to the motor

A) The number of times the voltage is turned on and off per second

4 / 8

Which of the following is a key benefit of using PWM for speed control in AC induction motors?

D) Increased electrical noise without power savings

A) High starting torque but poor speed control

C) Constant speed operation only

B) Minimal power loss and efficient motor operation

5 / 8

How does PWM achieve speed control in an AC induction motor?

A) By increasing the physical windings of the motor

D) By changing the motor's mechanical load

C) By directly altering the magnetic field strength of the motor

B) By adjusting the on-off pattern of voltage pulses to control the average voltage and current

6 / 8

What effect does PWM have on the waveform supplied to the motor?

C) It converts the waveform to a square wave

B) It modifies the AC waveform into discrete voltage pulses

D) It has no effect on the waveform

A) It produces a constant DC waveform

7 / 8

How does changing the duty cycle affect the motor’s performance?

D) It changes the motor from AC to DC operation

B) A higher duty cycle reduces the motor speed

A) A lower duty cycle increases the motor speed

C) Adjusting the duty cycle changes the average voltage and current supplied, impacting motor speed

8 / 8

In which scenario would PWM be most advantageous for motor control?

D) When using a single-phase motor only

B) In applications that require precise and efficient motor speed control

A) When high torque at startup is required but speed control is not needed

C) For motors that must run at a constant, maximum speed

Your score is