1
GATE EE 2007
+2
-0.6
A three-phase squirrel cage induction motor has a starting torque of $$150\%$$ and a maximum torque of $$300\%$$ with respect to rated torque at rated voltage and rated frequency. Neglect the stator resistance and rotational losses. The value of slip for maximum torque is
A
$$13.48\%$$
B
$$16.42\%$$
C
$$18.92\%$$
D
$$26.79\%$$
2
GATE EE 2007
+2
-0.6
A three phase squirrel cage induction motor has a starting current of seven times the full load current and full load slip of $$5\%$$

If a star-delta starter is used to start this induction motor, the per unit staring torque will be

A
$$0.607$$
B
$$0.816$$
C
$$1.225$$
D
$$1.616$$
3
GATE EE 2007
+2
-0.6
A three phase squirrel cage induction motor has a starting current of seven times the full load current and full load slip of $$5\%$$

If a starting torque of $$0.5$$ per unit is required then the per unit starting current should be

A
$$4.65$$
B
$$3.75$$
C
$$3.16$$
D
$$2.13$$
4
GATE EE 2006
+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
$$222.9$$ $$Nm$$
EXAM MAP
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