1
GATE EE 2001
Subjective
+5
-0
An ideal transformer has a linear $$B-H$$ characteristic with a finite slope and a turns ratio of $$1:1.$$ The primary of the transformer is energized with an ideal current source, producing the signal i as shown in figure. Sketch the shape (neglecting the scale factor) of the following signals, labeling the time axis clearly GATE EE 2001 Electrical Machines - Transformers Question 12 English

$$(a)$$ $$\,\,\,\,\,$$ the core flux $${\phi _{oc}}$$ with the secondary of the transformer open
$$(b)$$ $$\,\,\,\,\,$$ the open-circuited secondary terminal voltage $${V_2}\left( t \right).$$
$$(c)$$ $$\,\,\,\,\,$$ the short-circuited secondary current $${i_2}\left( t \right)$$
$$(d)$$ $$\,\,\,\,\,$$ the core flux $${\phi _{sc}},$$ with the secondary of the transformer short-circuited.

2
GATE EE 2001
MCQ (Single Correct Answer)
+1
-0.3
In case of an armature controlled separately excited dc motor drive with closed loop speed control, an inner current loop is useful because it
A
limits the speed of the motor to a safe value
B
helps in improving the drive energy efficiency
C
limits the peak current of the motor to the permissible value
D
reduces the steady state speed error
3
GATE EE 2001
MCQ (Single Correct Answer)
+2
-0.6
An electric motor with 'constant output power' will have a torque speed characteristic in the form of a
A
straight line through the origin
B
straight line parallel to the speed axis
C
circle about the origin
D
rectangular hyperbola
4
GATE EE 2001
MCQ (Single Correct Answer)
+1
-0.3
A single-phase transformer is to be switched to the supply to have minimum inrush current. The switch should be closed at
A
maximum supply voltage
B
zero supply voltage
C
$$\frac1{\sqrt2}$$ maximum supply voltage
D
$$\frac12$$ maximum supply voltage
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