1
GATE EE 1999
+2
-0.6
A 10 kVA, 400 V/200 V single-phase transformers with 10% impedance draws a steady short circuit line current of
A
50 A
B
150 A
C
250 A
D
350 A
2
GATE EE 1999
+2
-0.6
The windings of a Q kVA, $$\frac{V_1}{V_2}$$ Volt, three-phase, Delta connected, core type transformer are reconnected to work as a single phase transformer. The maximum voltage and the power ratings of the new configuration are,
A
$$\frac{3V_1}{3V_2},\;3Q$$
B
$$\frac{V_1}{V_2},\;Q/3$$
C
$$\frac{\sqrt3V_1}{\sqrt3V_2},\;2Q$$
D
$$\frac{\displaystyle\frac32V_1}{\displaystyle\frac32V_2},\;\frac Q2$$
3
GATE EE 1998
+2
-0.6
A 50 Hz transformer having equal hysteresis and eddy current losses at rated excitation is operated at 45 Hz at 90% of its rated voltage. Compared to rated operating point, the core losses under this condition:
A
reduce by 10%
B
reduce by 19%
C
reduce by 14.5%
D
remain unchanged
4
GATE EE 1997
+2
-0.6
A voltage $$V=400$$ sin $$314.16t$$ is applied to a $$1$$-phase transformer on no-load. If the no load current of the transformer is $$2\sin \left( {314.16t - {{85}^0}} \right),\,\,$$ then magnetization branch impedance will be approximately
A
$$141\,\,\angle 90$$
B
$$200\,\,\angle - 85$$
C
$$200\,\,\angle 85$$
D
$$282\,\,\angle - 80$$
EXAM MAP
Medical
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