62.

63.

64.

65,

66.

67,

68.

Circuit turn - off time of an SCR is defined as the time :

(ಗಿ) taken by the SCR turn to be off

(B) required for the SCR current to become zero

(८) for which the SCR is reverse biased to reduce its current below the holding current
(D) for which the SCR is reverse biased by the commutation circuit

When 15 a voltage source inverler normally used ?

(ಸಿ) Source inductance is large and load inductance is small
(ए) Source inductance is large and load inductance is large
(C) Source inductance is small and load inductance is small
(D) Source inductance is small and load inductance is large

A single - phase fully controlled thyristor bridge ac - dc converter is operating at a firing
angle of 25" and an overlap angle of 10° with constant dc output current of 20 A. The
fundamental power factor {displacement factor) at input ac mains is :

(ಗಿ) 0.827 © 6 (೦0) 0.78 (0) 09

HVDC transmission systems generally employ :
(A) 6 pulse converters (B) 3 pulse converters
(C) 12 pulse converters (D) either 12 or 6 pulse converters

Which of these commutation methods is used in AC-DC converters ?
(A) Class F 18 Class D (C) ‏فوفك‎ 0. (D) Class A

A single phase half wave rectifier circuit has a freewheeling diode which will conduct only
if

(|) ‏0۵٥‎ is combination of R and L

(B) load is purely inductive or combination of R and 1,

)6 load 15 purely resistive

(D) load is purely inductive

As compared to B[T, MOSFET has :

(^) higher switching losses and higher conduction losses
(B) lower switching losses and higher conduction losses
(€) higher switching losses and lower conduction losses
(10) lower switching losses and lower conduction losses

69, Which chopper circuit uses salurable reactor ? _
(ക) Morgan chopper (18) Auxiliary commutated ,
{C) Jones chopper (D) Load Commutated
213/2014 10 A

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