Aux 2 Unit 5 Quiz 4

Aux 2 Unit 5 Q4

1 / 8

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

B) It modifies the AC waveform into discrete voltage pulses

A) It produces a constant DC waveform

D) It has no effect on the waveform

C) It converts the waveform to a square wave

2 / 8

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

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

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

3 / 8

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

C) Constant speed operation only

B) Minimal power loss and efficient motor operation

D) Increased electrical noise without power savings

A) High starting torque but poor speed control

4 / 8

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

A) By increasing the physical windings of the motor

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

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

D) By changing the motor's mechanical load

5 / 8

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

C) Generation of electrical noise that may require filtering

D) Reduced lifespan of the motor

B) Increased torque at low speeds

A) Increased energy consumption

6 / 8

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

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

D) When using a single-phase motor only

7 / 8

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

C) To permanently increase the motor’s output power

A) To change the physical size of the motor

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

D) To reverse the direction of the motor

8 / 8

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

C) The total power supplied to the motor

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

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

D) The frequency of the AC supply

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