1) In current commutated DC-DC choppers, the voltage spike appears across the load when
a. Voltage across the commutating inductances collapses
b. The capacitance voltage adds to the supply voltage
c. Both (a) and (b)
d. None of these
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Answer
Explanation
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ANSWER: Both (a) and (b)
Explanation:
No explanation is available for this question!
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2) In a load commutated DC - DC chopper, the capacitor has a
a. Symmetric triangular voltage across itself
b. Symmetric rectangular voltage across itself
c. Symmetric trapezoidal voltage across itself
d. Symmetric sinusoidal voltage across itself
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Answer
Explanation
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ANSWER: Symmetric trapezoidal voltage across itself
Explanation:
No explanation is available for this question!
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3) Voltage commutation circuit can be converted into a current commutation by interchanging the positions of
a. Diode and capacitor
b. Capacitor and SCR
c. Inductor and capacitor
d. Capacitor and load
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Answer
Explanation
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ANSWER: Diode and capacitor
Explanation:
No explanation is available for this question!
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4) Between the incoming and outgoing devices in voltage commutation
a. Large overlapping takes place
b. Small overlapping operation
c. No overlapping operation
d. None of these
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Answer
Explanation
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ANSWER: No overlapping operation
Explanation:
No explanation is available for this question!
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5) During the commutation period in 3 phase converter, overlap time is
a. Dependent on the load current
b. Dependent on the voltage
c. Dependent on both the load current and load voltage behind the short circuit current
d. Independent on both the load current and load voltage
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Answer
Explanation
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ANSWER: Dependent on both the load current and load voltage behind the short circuit current
Explanation:
No explanation is available for this question!
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6) In a three phase converter, the number of notches per cycle is
a. One
b. Three
c. Six
d. Nine
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Answer
Explanation
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ANSWER: Six
Explanation:
No explanation is available for this question!
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7) If all the SCR’s of 3 phase PAC is replaced by diodes, they would be triggered
a. 120 degree after the zero crossing of the corresponding line voltages
b. 60 degree after the zero crossing of the corresponding line voltages
c. 120 degree before the zero crossing of the corresponding line voltages
d. 60 degree before the zero crossing of the corresponding line voltages
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Answer
Explanation
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ANSWER: 60 degree after the zero crossing of the corresponding line voltages
Explanation:
No explanation is available for this question!
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8) For commutation in three phase PAC, normally balanced three phase voltages VR, VY and VB are connected to the three legs of the converter via
a. Three inductances
b. Three capacitances
c. Three resistance
d. Three transistors
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Answer
Explanation
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ANSWER: Three inductances
Explanation:
No explanation is available for this question!
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9) In commutation PAC stands for
a. Permanent angle converter
b. Phase angle converter
c. Phase angle commutation
d. Phase and commutation
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Answer
Explanation
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ANSWER: Phase angle converter
Explanation:
No explanation is available for this question!
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10) In the operation and control of both naturally commutated and forced commutated SCR base converter, commutation plays an important role. The converters is / are
a. AC - DC
b. DC - DC
c. DC - AC
d. All of these
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Answer
Explanation
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ANSWER: All of these
Explanation:
No explanation is available for this question!
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