Electrical Machines
Induction Machines
Marks 1Marks 2
Synchronous Machines
Marks 1Marks 2Marks 5
1
GATE EE 2009
MCQ (Single Correct Answer)
+2
-0.6
A field excitation of $$20A$$ in a certain alternator results in a armature current of $$400$$ $$A$$ in short circuit and a terminal voltage of $$2000$$ $$V$$ on open circuit. The magnitude of the internal voltage drop with in the machine at a load current of $$200$$ $$A.$$
A
$$1$$ $$V$$
B
$$10$$ $$V$$
C
$$100$$ $$V$$
D
$$1000$$ $$V$$
2
GATE EE 2008
MCQ (Single Correct Answer)
+2
-0.6
A synchronous motor is connected to an infinite bus at $$1.0$$ $$p.u$$ voltage and draws $$0.6$$ $$pu$$ at unity power factor. Its synchronous reactance is $$1.0$$ $$pu$$ and resistance is negligible.

The excitation voltage and load angle will respectively be

A
$$0.8$$ $$pu$$ and $$36.86$$ degrees lag
B
$$0.8$$ $$pu$$ and $$36.86$$ degrees lead
C
$$1.17$$ $$pu$$ and $$30.96$$ degrees lead
D
$$1.17$$ $$pu$$ and $$30.96$$ degrees lag
3
GATE EE 2008
MCQ (Single Correct Answer)
+2
-0.6
A synchronous motor is connected to an infinite bus at $$1.0p.u$$ voltage and draws $$0.6$$ $$pu$$ at unity power factor. Its synchronous reactance is $$1.0$$ $$pu$$ and resistance is negligible.

Keeping the excitation voltage same, the load on the motor is increased such that the motor current increases by $$20\% $$. The operating power factor will become

A
$$0.995$$ lagging
B
$$0.995$$ leading
C
$$0.791$$ lagging
D
$$0.848$$ leading
4
GATE EE 2007
MCQ (Single Correct Answer)
+2
-0.6
A $$100$$ $$kVA$$, $$415V,$$ star connected synchronous machine generates rated open circuit voltage $$415V$$ at a field current of $$15A.$$ The short circuit armature current at a field current of $$10A$$ is equal to the rated armature current. The per unit saturated synchronous reactance is
A
$$1.731$$
B
$$1.5$$
C
$$0.666$$
D
$$0.577$$
GATE EE Subjects
Electromagnetic Fields
Signals and Systems
Engineering Mathematics
General Aptitude
Power Electronics
Power System Analysis
Analog Electronics
Control Systems
Digital Electronics
Electrical Machines
Electric Circuits
Electrical and Electronics Measurement