1
GATE EE 2005
MCQ (Single Correct Answer)
+2
-0.6
Two magnetic poles revolve around a stationary armature carrying two coils ($$c_1-c'_1$$ , $$c_2-c'_2$$ ) as shown in Figure. Consider the instant when the poles are in a position as shown. Identify the correct statement regarding the polarity of the induced emf at this instant in coil sides $$c_2$$ and $$c_1$$. GATE EE 2005 Electrical Machines - D.C Machines Question 62 English
A
$$\odot\;in\;c_1$$, no emf in c2
B
$$\otimes\;in\;c_1$$, no emf in c2
C
$$\odot\;in\;c_2$$, no emf in c1
D
$$\otimes\;in\;c_2$$, no emf in c1
2
GATE EE 2005
MCQ (Single Correct Answer)
+2
-0.6
In a single phase induction motor driving a fan load, the reason for having a high resistance rotor is to achieve
A
low starting torque
B
quick acceleration
C
high efficiency
D
reduced size
3
GATE EE 2005
MCQ (Single Correct Answer)
+2
-0.6
A three-phase cage induction motor is started by direct-on-line (DOL) switching at the rated voltage. If the starting current drawn is 6 times the full load current, and the full load slip is 4%, the ratio of the starting developed torque to the full load torque is approximately equal to
A
0.24
B
1.44
C
2.40
D
6.00
4
GATE EE 2005
MCQ (Single Correct Answer)
+2
-0.6
Under no load condition, if the applied voltage to an induction motor is reduced from the rated voltage to half the rated value,
A
the speed decreases and the stator current increases
B
both the speed and the stator current decrease
C
the speed and the stator current remain practically constant
D
there is negligible change in the speed but the stator current decreases