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

Power Electronics (3140915) MCQs

MCQs of AC-DC Converters

Showing 81 to 90 out of 107 Questions

81.

In a single-phase half-wave circuit with RL load, and a freewheeling diode across the load, extinction angle β is more than π. For a firing angle a, the SCR and freewheeling diode would conduct, respectively, for

(a)	π-α, β
(b)	β-α, π-α
(c)	π-α, β-π
(d)	π-α, π-β

82.

In a single-phase one-pulse circuit with RL load and a freewheeling diode, extinction angle β is less than π. For a firing angle a, the SCR and freewheeling diode would, respectively, conduct for

(a)	β-α, 0°
(b)	π-α, &pi-β
(c)	α, β-α
(d)	β-α, α

83.

A single-phase full-wave mid-point thyristor converter uses a 230/200 V transformer with center tap on the secondary side. The P.I.V. per thyristor is

(a)	100 V
(b)	141.4 V
(c)	200 V
(d)	282.8 V.

84.

In a single-phase full converter bridge, the average output voltage is given by

(a)	$\frac{1}{π} \int_{α}^{π + α} V_{m} \cos θ d θ$
(b)	$\frac{1}{π} \int_{0}^{π + α} V_{m} \cos θ d θ$
(c)	$\frac{1}{π} \int_{α - \frac{π}{2}}^{α + \frac{π}{2}} V_{m} \cos θ d θ$
(d)	$\frac{1}{π} \int_{\frac{π}{2} - 1}^{α + \frac{π}{2}} V_{m} \cos θ d θ$

85.

In a single-phase semiconverter, the average output voltage is given by

(a)	$\frac{1}{π} \int_{α}^{π} V_{m} \cos θ d θ$
(b)	$\frac{1}{π} \int_{\frac{π}{2} - α}^{\frac{π}{2} + α} V_{m} \cos θ d θ$
(c)	$\frac{1}{π} \int_{α - \frac{π}{2}}^{\frac{π}{2}} V_{m} \cos θ d θ$
(d)	$\frac{1}{π} \int_{α - \frac{π}{2}}^{π} V_{m} \cos θ d θ$

86.

In a single-phase full converter, for continuous conduction, each pair of SCRs conduct for

(a)	π-α
(b)	π
(c)	α
(d)	π+α

87.

In controlled rectifiers, the nature of load current, i.e. whether load current is continuous or discontinuous

(a)	does not depend on type of load and firing angle delay
(b)	depends both on the type of load and firing angle delay
(c)	depends only on the type of load
(d)	depends only on the firing angle delay.

88.

In a single-phase full converter, if output voltage has peak and average values of 325 V and 133 V respectively, then the firing angle is

(a)	40°
(b)	140°
(c)	50°
(d)	130°

89.

In a single-phase semiconverter, if output voltage has peak and average values of 325 V and 133 V respectively, the firing angle is

(a)	40°
(b)	140°
(c)	73.40°
(d)	80°

90.

Each diode of a 3-phase half-wave diode rectifier conducts for

(a)	60°
(b)	120°
(c)	180°
(d)	90°

Showing 81 to 90 out of 107 Questions