Question

1. Transformer with three legs A, B and C in case of homogenous the first leg A has coil with 3 Henry, what is the Henry at leg C
a. 0.5 H
b. 1 H
c. 2 H
d. 2.5 H

2. If a carrier wave of 10MHz is amplitude modulated by an audio signal of 1 kHz, the resultant signal to be broadcast contains only the:
(A) 10,001,000-Hz component
(B) 10,001,000-Hz and 9,999,000-Hz components

(C) 10,001,000-Hz, 10,000,000-Hz, and 9,999,000-Hz components
(D) 10,001,000-Hz, 10,000,000-Hz, 9,999,000-Hz, and 1,000-Hz components

3. The minimum size THWN copper conductors rated at 75°C installed in conduit required to serve a continuous duty 230-V 10-hp single-phase induction motor and non-continuous l-kW resistance heater on a circuit operating at 240-V single phase are:
(A) 4/0 AWG
(B) 2/0 AWG
(C) 4 AWG
(D) 6 AWG

4. A squirrel-cage induction motor is rated 40 hp, 460 V, 3 phase, 60 Hz, 52 A, 0.87 lagging power factor at full load, Design E. The maximum locked-rotor current (amperes) for selection of the motor disconnect is most nearly:
(A) 412
(B) 356
(C) 300
(D) 240

5. You have sized branch-circuit conductors supplying a 3-phase squirrel-cage induction motor. Now
you must size the fuses to protect those conductors against short circuit or ground faults. What is the correct approach?
(A) The maximum fuse rating is the ampacity of the conductors, except the next larger size fuses can be used if the conductor ampacity does not match a standard fuse size.
(B) The maximum fuse rating is 125% of the full-load current of the motor.
(C) The maximum fuse rating is 100% of the locked-rotor current of the motor.
(D) None of the above.

6. The diagram below represents the Thevenin equivalent of a single-phase distribution system. A fault occurs between point X and ground. RF represents the
fault resistance. The current IF is 3,600 A when RF is 0 Q. If RF is changed to 1.0 Q, the current IF (amperes) is most nearly:
(A) 2,000
(B) 2,400
(C) 3,200
(D) 4,600

0000 V = 7,200 Vrms ERE

Answer 1

Miracle Page Data Ansi ll TFT Homagoricus calor se coulc is Most Necisty to 3 tso it means Coil c is of 2.54 - Ant. is d. 2.54 Ans: 3 ? Viburning for continous duty at 256 Indruction Motor for 230v, 10 he 1? 10x 7 AS 130 _32.43 A inte 131 _ L I La and Non Continuous at 240V operating hoatar of 1 W I, 4.17A Ix103 240 so for total current ou I - I +1, 2. 36.6A. So wire gange selected such that it can carry Current minimim 03 6.6 A wove so for this current rating and for Copper Conductor at 45°c wire gauge is 6 AWG Coll

ANS- 4 (D) 240

ANS- 5 (B) The Maximum Fuse rating id 125% of the full load Current of Motor.

Ans. 6. mo IZRA V27200 If RF =0 when If > 3600 wow, Rt changed to i v= ff xs Iso, v= If (Xs + Rp) Xv __7200 ____3600 ____X. 22 T, V ____AR 72007 2 +1 TF - 2400 (B) म