66.

67.

68.

69.

70.

71

72.

78.

In a 0// ೦೦೫೦1106 induction motor which runs at 50 Hz and rated voltage, the speed was
found to be 1440 rpm. If the machine runs at 850 rpm at 30 Hz, what is the slip?

(^) 0.03 © 6

(೧) 0.04 D) 0.0556

The maximum efficiency of an induction motor occurs at 4 kw. What will be the rating of the
machine?

(5) ணை B) 4kw

{© 35kw യ) ഭി

A field excitation of 20 A in a certain alternator results 10 an armature current of 400 A in
short circuit and a terminal voltage of 2000 V in open circuit. The magnitude of internal
voltage drop within the machine at a load current of 200 A is :

(ക 1500V ۱ (B) 2000V

(©) 1000V യ 100V

A synchronous motor is connected to an infinite bus at 1.0 pu voltage and draws 1.0 pu
current at unity power factor. The synchronous reactance is 1.0 pu and resistance is
negligible. What is the load angle?

@) 90 രു 455

0.0 (D) 60९

If the field excitation of a salient pole synchronous generator is removed, what will happen to
the machine?

(ಯ) Machine will stop

(B) Speed will be halved

(C) Machine will burn

(D) Continue run at the same speed as motor

The leakage resistance of a 100 km long cable is 1m . For a length of 50 km, the resistance
will be : ⋅

(4) 2 ०६ @) 10

ര 480 D) 0.88೧

For an induction motor, it was found that the no load and full load currents are almost the
same. The reason is :

(ಯ) motor is faulty

(B) ammeter used is faulty

(@ windings may have burnt

(D) it is possible for some machines to have full load and no load currents equal

Two power plants P, and P, are connected by a lossy line with loss coefficients B,, =0.001,
By, =0.0005, B, =-0.0001. What is the power loss for generations P, =50 MW,

P, =100 MW ?
(4) 2521 ൫ 1017
© 584% © 7

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