1
GATE EE 2004
MCQ (Single Correct Answer)
+2
-0.6
The armature resistance of a permanent magnet dc motor is 0.8 $$\Omega$$. At no load, the motor draws 1.5 A from a supply voltage of 25 V and runs at 1500 rpm. The efficiency of the motor while it is operating on load at 1500 rpm drawing a current of 3.5 A form the same source will be
A
48.0%
B
57.1%
C
59.2%
D
88.8%
2
GATE EE 2004
MCQ (Single Correct Answer)
+1
-0.3
For a linear electromagnetic circuit, the following statement is true.
A
Field energy is equal to the co-energy
B
Field energy is greater than the co-energy
C
Field energy is lesser than the co-energy
D
Co-energy is zero
3
GATE EE 2004
MCQ (Single Correct Answer)
+1
-0.3
The direction of rotation of a 3-phase induction motor is clockwise when it is supplied with 3-phase sinusoidal voltage having phase sequence A-B-C. For counter clockwise rotation of the motor, the phase sequence of the power supply should be
A
B-C-A
B
C-A-B
C
A-C-B
D
B-C-A or C-A-B
4
GATE EE 2004
MCQ (Single Correct Answer)
+2
-0.6
A 8 pole, DC generator has a simplex wave-wound armature containing 32 coils of 6 turns each. Its flux per pole is 0.06 Wb. The machine is running at 250 rpm. The induced armature voltage is
A
96V
B
192V
C
384V
D
768V