POWER Electronics(700-MCQ)

 

Q-The below given output voltage waveform can be obtained by a

power-electronics-questions-answers-ac-voltage-controllers-2-q5

a) half wave ac voltage controller
b) full wave ac voltage controller
c) full wave inverter circuit
d) none of the mentioned

…………..

Answer: b
Explanation: As the control is in both the directions or cycles, it is a full wave ac voltage controller circuit.

 

 

 

Q-The below given output voltage waveform can be obtained by a

power-electronics-questions-answers-ac-voltage-controllers-2-q3

a) half wave ac voltage controller
b) full wave ac voltage controller
c) half wave controller with firing angle = 0° for T1
d) full wave controller with firing angle = 0° for both T1 and T2

………………………..

Answer: a
Explanation: As the positive half is chopped off due to some value of firing angle, the firing angle is not equal to zero. As the negative half is a half sine wave, either it is a full wave controller with firing angle for T2 set to zero or it is a half wave controller with a Thyristor (T1) and a diode.

 

Q-In the below shown AC converter circuit with firing angle = α for both the devices, T2 will conduct from

power-electronics-questions-answers-ac-voltage-controllers-2-q4

a) α to π
b) π + α to 2π
c) π to 2π
d) α to 2π

……………

Answer: b
Explanation: T2 is triggered at π + α, it conducts from π + α to 2π after which it is line commutated.

 

 

Q-Find the power delivered to the load in the integral cycle control method of ac voltage control, having a sine input of Vs, R load and duty cycle = k.

power-electronics-questions-answers-ac-voltage-controllers-2-q4

 

a) Vs2/R
b) k.Vs2/R
c) √k .Vs2/R
d) 0

……………

Answer: b
Explanation: Output voltage = Vs x √k
P = (Vs x √k)2/R.

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