24.

25.

26.

27.

28.

29.

The system y(t) = x" (t) is:
(A) Linear and non invertible (B) Non linear and non invertible
(C) Linear and invertible (D) Non linear and invertible

A 125 V, 50 Hz, single phase transformer has rated eddy current loss of 125 W. If the
transformer is operated from 200 V, 40 Hz supply mains, then new eddy current loss is :

(A) 125 W (B) 160W
(0) 2508 (D) 320W

A 500 kVA transformer with 0.05 p.u. reactance is connected in parallel with a 250 kVA
transformer with 0.04 p.u. reactance. The secondary voltage of each transformer is 400 V on
no-load. Find the common load they can share without over loading any transformer at unity
power factor :

(A) 600 kVA (B) 625 kVA
(© 650 kVA (D) 675 kVA

A rectangular coil loop with effective conductor side length 1, axial radius of the loop r,
rotating at an angular velocity w, in a steady magnetic flux density B, then the e.m.f. induced
in the loop is given by :

(0) Blw (B) ‏ساط‎

(0 Blwr ൯൩) 2Blwr

Identify correct and incorrect statements related to armature reaction and commutation
process in DC machine :

]. In a DC motor, due to armature reaction, the shift in magnetic neutral axis is in same
direction of rotation.

11. The polarity of the interpoles must be of the same polarity as the next upcoming main
pole ina DC generator.

111. Compensating winding cancel the armature reaction effect, but not ൧൪ effect.

(^) land II are correct, but III is incorrect
(8) Tis correct, but II and III are incorrect
(0 Tand II are incorrect, but III is correct
(1) Tisincorrect, but I and III are correct

Torque and speed relationship in a DC series motor is given by:

1 1
൯) o«—
क Tin Tin

© Yous 0 ५०

(^) ७०

Tin

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