1
GATE EE 2014 Set 2
Numerical
+2
-0
A synchronous generator is connected to an infinite bus with excitation voltage $${E_f} = 1.3\,pu.$$ The generator has a synchronous reactance of $$1.1$$ $$pu$$ and is delivering real power $$(P)$$ of $$0.6$$ $$pu$$ to the bus. Assume the infinite bus voltage to be $$1.0$$ $$pu.$$ Neglect stator resistance. The reactive power $$(Q)$$ in $$pu$$ supplied by the generator to the bus under this condition is ____________.
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2
GATE EE 2014 Set 2
MCQ (Single Correct Answer)
+2
-0.6
A $$20$$-pole alternator is having $$180$$ identical stator slots with $$6$$ conductors in each slot. All the coils of a phase are in series. If the coils are connected to realize single-phase winding, the generated voltage is $${V_1}.$$ If the coils are reconnected to realize three-phase star-connected winding, the generated phase voltage is $${V_ 2}.$$ Assuming full pitch, single-layer winding, the ratio $${V_1}/{V_2}$$ is
A
$${1 \over {\sqrt 3 }}$$
B
$${1 \over 2}$$
C
$${\sqrt 3 }$$
D
$$2$$
3
GATE EE 2014 Set 2
MCQ (Single Correct Answer)
+1
-0.3
In a constant V/f control of induction motor, the ratio V/f is maintained constant from 0 to base frequency, where V is the voltage applied to the motor at fundamental frequency f. Which of the following statements relating to low frequency operation of the motor is TRUE?
A
At low frequency, the stator flux increases from its rated value.
B
At low frequency, the stator flux decreases from its rated value.
C
At low frequency, the motor saturates.
D
At low frequency, the stator flux remains unchanged at its rated value.
4
GATE EE 2014 Set 2
Numerical
+2
-0
A 250 V dc shunt machine has armature circuit resistance of 0.6 $$\Omega$$ and field circuit resistance of 125 $$\Omega$$. The machine is connected to 250 V supply mains. The motor is operated as a generator and then as a motor separately. The line current of the machine in both the cases is 50 A. The ratio of the speed as a generator to the speed as a motor is ____________.
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