1
GATE EE 2006
MCQ (Single Correct Answer)
+2
-0.6
A $$3$$ phase, $$4$$ pole, $$400$$ $$V,$$ $$50$$ $$Hz,$$ star connected induction motor has following circuit parameters $${r_1} = 1.0\Omega ,\,{r_2} = 0.5\Omega ,$$ $${\mkern 1mu} {\mkern 1mu} {\mkern 1mu} {x_1} = x{'_2} = 1.2\Omega ,{\mkern 1mu} {x_m} = 35\Omega $$
The starting torque when the motor is started direct-on-line is (use approximate equivalent circuit model)
A
$$63.6$$ $$Nm$$
B
$$74.3$$ $$Nm$$
C
$$190.8$$ $$Nm$$
D
$$222.9$$ $$Nm$$
2
GATE EE 2006
MCQ (Single Correct Answer)
+2
-0.6
A $$300$$ $$kVA$$ transformer has $$95\% $$ efficiency at full load $$0.8$$ $$pf$$ lagging and $$96\% $$ efficiency at half load, unity $$pf.$$

What is the maximum efficiency (in %) at unity $$pf$$ load?

A
$$95.1$$
B
$$96.2$$
C
$$96.4$$
D
$$98.1$$
3
GATE EE 2006
MCQ (Single Correct Answer)
+2
-0.6
Two transformers are to be operated in parallel such that they share load in proportion to their $$kVA$$ ratings. The rating of the first transformer is $$500$$ $$kVA$$ and its $$pu$$ leakage impedance is $$0.05$$ $$pu.$$ If the rating of second transformer is $$250$$ $$kVA,$$ its $$pu$$ leakage impedance is
A
$$0.20$$
B
$$0.10$$
C
$$0.25$$
D
$$0.025$$
4
GATE EE 2006
MCQ (Single Correct Answer)
+2
-0.6
A $$300$$ $$kVA$$ transformer has $$95\% $$ efficiency at full load $$0.8$$ $$pf$$ lagging and $$96\% $$ efficiency at half load, unity $$pf.$$

The iron loss $$\left( {{P_i}} \right)$$ in $$kW,$$ under full load operation are

A
$${P_c} = 4.12,\,\,{P_i} = 8.51$$
B
$${P_c} = 6.59,\,\,{P_i} = 9.21$$
C
$${P_c} = 8.51,\,\,{P_i} = 4.12$$
D
$${P_c} = 12.72,\,\,{P_i} = 3.07$$
EXAM MAP