1
GATE EE 2003
+2
-0.6
Figure shows a $$\triangle$$ - Y connected 3-phase distribution transformer used to step down the voltage from 11000 V to 415 V line-to line. It has two switches S1 and S2. Under normal conditions S1 is closed and S2 is open. Under certain special conditions S1 is open and S2 is closed. In such a case the magnitude of the voltage across the LV terminals a and c is
A
240 V
B
480 V
C
415 V
D
0 V
2
GATE EE 2003
+2
-0.6
Figure shows an ideal three-winding transformer. The three windings 1,2,3 of the transformer are wound on the same core as shown. The turn's ratio N1:N2:N3 is 4:2:1. A resistor of 10 Ω is connected across winding-2. A capacitor of reactance 2.5 Ω is connected across winding-3. Winding-1 is connected across a 400 V, ac supply. If the supply voltage phasor $$\overline V=400\angle0^\circ$$, the supply current phasor $${\overline I}_1$$ is given by
A
(-10 + j10) A
B
(-10 - j10) A
C
(10 + j10) A
D
(10 - j10) A
3
GATE EE 2002
+2
-0.6
A 400V/200V/200V, 50 Hz three winding transformer is connected as shown in Figure. The reading of the voltmeter 'V' will be
A
0 V
B
400 V
C
600 V
D
800 V
4
GATE EE 2001
+2
-0.6
A 3-phase transformer has rating of 20 MVA, 220 kV (star) / 33 kV (delta) with leakage reactance of 12%. The transformer reactance (in ohms) referred to each phase of the L.V. delta-connected side is
A
23.5
B
19.6
C
18.5
D
8.7
EXAM MAP
Medical
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