# A fully controlled natural commutated 3-phase bridge rectifier is operating with a firing angle α = 30o. The peak to peak voltage ripple expressed as a ratio of the peak output dc voltage at the output of the converter bridge is

1.   0.5

2.

3.

4.

4

0.5

Explanation :
No Explanation available for this question

# A phase-controlled half-controlled single-phase converter is shown in the given figure. The control angle α = 30o. The output dc voltage wavesshape will be as shown in

1.

2.

3.

4.

4 Explanation :
No Explanation available for this question

# With reference to the output wave form given in the figure below, output of the converter will be free from 5th harmonic, when

1.  α = 72o

2.  α = 36o

3.  α = 150o

4.  α = 120o

4

α = 72o

Explanation :
No Explanation available for this question

# In a 3-phase half-wave diode rectifier if Vm is the maximum value of per phase voltage, then each diode is subjected to a peck inverse voltage of

1.  Vm

2.

3.  2Vm

4.   3Vm

4 Explanation :
No Explanation available for this question

# A 3-phase full converter has an average output voltage of 200 V for zero degree firing angle and for resistive load. For a firing angle of 90o, the output voltage would be

1.  0 V

2.  50 V

3.  100 V

4.   26.8 V

4

0 V

Explanation :
No Explanation available for this question

# A dc to dc transistor chopper supplied from a fixed voltage dc source feeds a fixed resistive-inductive load and a free-wheeling diode. The chopper operates at 1 kHz and 50% duty cycle. Without changing the value of the average dc current through the load, if it is desired to reduce the ripple content of load current, the control action needed will

1.  increase chopper frequency keeping the duty cycle constant

2.  increases chopper frequency and duty cycle in equal ratio

3.  decrease only the chopper frequency

4.  decrease only the duty cycle.

4

increase chopper frequency keeping the duty cycle constant

Explanation :
No Explanation available for this question

# A voltage commutated chopper has the following parameters : Vs = 200 V, Load circuit parameter 1 Ω, 2 mH, 5V. Communication circuit parameter : L = 25 μH, C = 50 μF. For constant load current at 100 A, the effective ON period and peak current through the main thyristor are respectively

1.  1000 μS, 200 A

2.  700 μS, 382.8 A

3.  1000 μS, 282.8 A

4.  1000 μS, 382.8 A

4

700 μS, 382.8 A

Explanation :
No Explanation available for this question

# In type A chopper source voltage is 100 V, d.c. ON period = 100 μS, OFF-period = 150 μs and load RLE consists of R = 2Ω, L = 5mH, E = 10 V. For continuous conduction average output voltage and average output current for this chopper are respectively

1.  40 V, 5 A

2.  66.66 V 28.33 A

3.  60V, 25 A

4.  40V, 20 A

4

40 V, 5 A

Explanation :
No Explanation available for this question

# A chopper operating at a fixed frequency is feeding an R-L load. As duty ratio of the chopper is increased from 25% to 75%, the ripple in the load current

1.  remains constant

2.  decreases, reachs a minimum at 50% duty ratio and then increases

3.  increases, reaches a maximum at 50% duty ratio and then decreases

4.  keeps on increasing as the duty ratio is increased

4

remains constant

Explanation :
No Explanation available for this question

1.  1.6 A

2.  6.4 A

3.  8.0 A

4.   10.0 A

4