MCQs of AC-DC Converters (Power Electronics - 3140915)

Power Electronics (3140915) MCQs

MCQs of AC-DC Converters

Showing 91 to 100 out of 107 Questions

91.

Each diode of a 3-phase, 6-pulse (full-wave) bridge diode rectifier conducts for

(a)	60^o
(b)	120^o
(c)	180^o
(d)	90^o

92.

In a 3-phase half-wave diode rectifier, if per phase input voltage is 200 V, then the average output voltage is

(a)	233.91 V
(b)	116.95 V
(c)	202.56 V
(d)	101.28 V

93.

For a 3-phase, six-pulse diode rectifier, the average output voltage in terms of maximum value of line voltage Vm is

(a)	$\frac{3 \sqrt{2}}{π} V_{m}$
(b)	$\frac{3}{π} V_{m}$
(c)	$\frac{3 \sqrt{3}}{2 π} V_{m}$
(d)	$\frac{3 \sqrt{3}}{π} V_{m}$

94.

In a 3-phase half-wave rectifier, dc output voltage is 230 V. The peak inverse voltage across each diode is

(a)	481.7 V
(b)	460 V
(c)	345 V
(d)	230 V

95.

In a 3-phase semi-converter, for firing angle less than or equal to 60°, freewheeling diode conducts for

(a)	30°
(b)	60°
(c)	90°
(d)	0°

96.

In a 3-phase full converter, three SCRs pertaining to one group are fired at an interval of

(a)	30°
(b)	60°
(c)	90°
(d)	120°

97.

For a single-phase phase-controlled rectifier, with a freewheeling diode across the load,

(a)	the instantaneous output voltage v₀ is always positive
(b)	v₀ may be positive or zero
(c)	v₀ may be positive, zero or negative
(d)	v₀ is always zero or negative

98.

In a single-phase full converter, if load current is I and ripple free, than average thyristor current is

(a)	(1/2) . I
(b)	(1/3) . I
(c)	(1/4) . I
(d)	I

99.

In a 3-phase full converter, if load current is I and ripple free, then average thyristor current is

(a)	(1/2) . I
(b)	(1/3) . I
(c)	(1/4) . I
(d)	I

100.

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 90 degree, the output voltage would be

(a)	0
(b)	50 V
(c)	100 V
(d)	26.8 V

Showing 91 to 100 out of 107 Questions