=

68. Which of the following statements is/are true regarding mechanical characteristic of a
de shunt motor ?
i. Itis the graph between torque and speed of motor.
॥. Itis the graph between armature current and armature torque.
iii. The shape of the characteristic is linear.
iv. The shape of the characteristics is hyperbolic.
A) Only i and iv B) Only ii and iii
C) Only i and iii D) Only ii and iv

. During the no load test on a 200 ۷, DC shunt motor having armature resistance 010.1 ೧
and field resistance of 200 ൨, the armature current is recorded to be 10 A. The constant
loss of the motor is

A) 2000 W 8) 1990 W

C) 2200 W 0) 2190 W

. ADC shunt motor is running at 1500 rpm. An additional resistance is introduced in the field
Circuit of the motor without any change in applied voltage. The speed of the motor is

A) Will remain the same

B) Will be more than 1500 rpm

C) Will be less than 1500 rpm

D) Will reduce to zero

. Ifthe input supply frequency of a transformer is doubled, keeping the input voltage constant
which of the following statements are true ?
1. Core loss gets doubled.
8. Eddy current loss gets doubled.
_ അ. Hysteresis loss reduces.

A) Only i and ii B) Only iii
©) Only i D) Only ii
. The purpose of using laminations in a transformer is to reduce
A) Eddy current loss B) Hysteresis loss
C) Copper loss D) Friction and windage loss

. The rotor EMF frequency of a 3 phase induction motor is found to be 2 Hz and the input
Supply frequency to the motor is 50 Hz. Calculate the percentage slip of the motor.
A) 6% B) 8% C) 4% D) 5%

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