Electrical Machines
Induction Machines
Marks 1Marks 2
Synchronous Machines
Marks 1Marks 2Marks 5
1
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
2
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
$$0.577$$
3
GATE EE 2007
MCQ (Single Correct Answer)
+2
-0.6
A $$3$$ phase, $$3$$ stack, variable reluctance stepper motor has $$20$$ poles on each rotor and stator stack. The step angle of this stepper motor is
A
$$3$$ degrees
B
$$6$$ degrees
C
$$9$$ degrees
D
$$18$$ degrees
4
GATE EE 2006
MCQ (Single Correct Answer)
+2
-0.6
A $$3$$-phase $$4000$$ $$V,$$ $$5$$ $$kW,$$ star connected synchronous motor having an internal reactance of $$10$$ $$ohms$$ is operating at $$50\% $$ load, unity power factor. Now, the excitation is increased by $$1\% $$, what will be the new load in percent, if the power factor is to be kept same? Neglect all losses and consider linear magnetic circuit.
A
$$67.9\% $$
B
$$56.9\% $$
C
$$51\% $$
D
$$50\% $$
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