Power Electronics (3140915) MCQs

MCQs of AC-DC Converters

Showing 61 to 70 out of 107 Questions
4 5 6 7 8 9
61.
Each SCR of a 3-phase 6-pulse converter conducts for
(a) 120 degrees
(b) 60 degrees
(c) 180 degrees
(d) 360 degrees
Answer:

Option (a)

62.
The effect of source inductance on the performance of a 3-phase controlled converter is to
(a) increase the average load voltage
(b) reduce the average load voltage
(c) make the load current continuous
(d) remove ripples from the load current
Answer:

Option (b)

63.
In a 3-phase full wave converter, if V is the maximum value of line voltage at the input, then each SCR is subjected to a peak negative voltage of
(a) V
(b) 3V
(c) √3V
(d) V/2
Answer:

Option (c)

64.
Which of the following converter circuits would require a neutral point?
(a) 3-phase semi-converter
(b) 3-phase full converter
(c) 3-phase full converter with freewheeling diode
(d) 3-phase half wave converter
Answer:

Option (d)

65.
Semi-converters are
(a) single quadrant converters
(b) double quadrant converters
(c) three quadrant converters
(d) none of the mentioned
Answer:

Option (a)

66.
Dual converters provide
(a) two quadrant operation
(b) three quadrant operation
(c) four quadrant operation
(d) none of the mentioned
Answer:

Option (c)

67.
A dual converters has
(a) two full converters in series
(b) two half converters in series
(c) two full converters in anti-parallel
(d) two half converters in anti-parallel
Answer:

Option (c)

68.
The major advantage of using dual converters is that
(a) it is cheaply available
(b) it has better pf
(c) no mechanical switch is required to change the mode of operation
(d) its operating frequency is very high
Answer:

Option (c)

69.
The four quadrant operation of dual converters can be obtained by
(a) moving the mechanical lever
(b) adding inductance to the circuit
(c) changing the firing angle value
(d) none of the mentioned
Answer:

Option (c)

70.
A single full converter alone can given a
(a) four quadrant operation
(b) three quadrant operation
(c) two quadrant operation
(d) none of the mentioned
Answer:

Option (c)

Showing 61 to 70 out of 107 Questions
4 5 6 7 8 9