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GATE EE 2015 Set 2
Numerical
+1
-0
The figure shows the per-phase equivalent circuit of a two-pole three-phase induction motor operating at 50 Hz. The 'air-gap' voltage, Vg across the magnetizing inductance, is 210Vrms, and the slip, s, is 0.05. The torque (in Nm) produced by the motor is ________. GATE EE 2015 Set 2 Electrical Machines - Induction Machines Question 64 English
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2
GATE EE 2015 Set 2
MCQ (Single Correct Answer)
+1
-0.3
A 4-pole, separately excited, wave wound DC machine with negligible armature resistance is rated for 230 V and 5 kW at a speed of 1200 rpm. If the same armature coils are reconnected to form a lap winding, what is the rated voltage (in volts) and power (in kW) respectively at 1200 rpm of the reconnected machine if the field circuit is left unchanged?
A
230 and 5
B
115 and 5
C
115 and 2.5
D
230 and 2.5
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GATE EE 2015 Set 2
Numerical
+2
-0
With an armature voltage of 100 V and rated field winding voltage, the speed of a separately excited DC motor driving a fan is 1000 rpm, and its armature current is 10 A. The armature resistance is 1 Ω. The load torque of the fan load is proportional to the square of the rotor speed. Neglecting rotational losses, the value of the armature voltage (in Volt) which will reduce the rotor speed to 500 rpm is ______.
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4
GATE EE 2015 Set 2
MCQ (Single Correct Answer)
+2
-0.6
A balanced (positive sequence) three-phase AC voltage source is connected to a balanced, star connected load through a star-delta transformer as shown in the figure. The line-to-line voltage rating is 230 V on the star side, and 115 V on the delta side. If the magnetizing current is neglected and $${\overline{\mathrm I}}_\mathrm s=100\angle0^\circ$$, then what is the value of $${\overline{\mathrm I}}_\mathrm p$$ in Ampere? GATE EE 2015 Set 2 Electrical Machines - Transformers Question 74 English
A
50$$\angle30^\circ$$
B
50$$\angle-30^\circ$$
C
50$$\sqrt3\angle30^\circ$$
D
200$$\angle30^\circ$$