Power Electronics (3140915) MCQs

MCQs of AC-DC Converters

Showing 71 to 80 out of 107 Questions
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71.
In non-circulating current mode dual converters, the circulating current is avoided by
(a) connecting a series reactor
(b) maintaining α1 + α2 = 180°
(c) operating only one converter
(d) adding an extra SCR
Answer:

Option (c)

72.
In circulating current mode dual converters, the circulating current is avoided by
(a) connecting a series reactor
(b) maintaining α1 + α2 = 180°
(c) operating only one converter
(d) adding an extra SCR
Answer:

Option (a)

73.
Choose the correct statement
(a) Circulating current exists only in circulating current mode
(b) Circulating current exists only in non-circulating current mode
(c) Circulating current exists in both the circulating and non-circulating current mode
(d) none of the mentioned
Answer:

Option (c)

74.
What causes circulating current in dual converters?
(a) Temperature issues
(b) Inductance in load circuit
(c) Out of phase voltages from both the converters
(d) none of the mentioned
Answer:

Option (c)

75.
In case of three-phase dual converter, one of the converter circuits is fired at an angle of 60°. For both the converter circuits to have equal average output voltage, what is the value of the firing angle for the other converter circuit?
(a) 60°
(b) 120°
(c) 100°
(d) Insufficient data
Answer:

Option (b)

76.
In case of circulating current type dual converters, the reactor is inserted between
(a) supply and converter
(b) across the load
(c) between the converters
(d) no reactor is used in case of circulating type dual converter
Answer:

Option (c)

77.
Circulating current flows
(a) from load to converters
(b) from one converter to another converter
(c) in the whole circuit
(d) none of the mentioned
Answer:

Option (b)

78.
The reactor in circulating current type dual converters
(a) increases losses
(b) reduces power factor
(c) increase the weight of the circuit
(d) all of the above
Answer:

Option (d)

79.
A single-phase half-wave controlled rectifier has 400 sin 314 t as the input voltage and R as the load. For a firing angle of 60° for the SCR, the average output voltage is
(a) 400/π
(b) 300/π
(c) 240/π
(d) 200/π
Answer:

Option (a)

80.
A single-phase one-pulse controlled circuit has resistance and counter emf load and 400 sin 314 t as the source voltage. For a load counter emf of 200 V, the range of firing angle control is
(a) 30° to 150°
(b) 30° to 180°
(c) 60° to 120°
(d) 60° to 180°
Answer:

Option (a)

Showing 71 to 80 out of 107 Questions
5 6 7 8 9 10