DDA JE Electrical ME 3 April 2023 Shift 1 Part 2

Q.21 In split phase induction motor, the starting torque is_____of the full load torque.

1. 100 to 125%
2. 50 to 75%
3. 150 to 200%
4. 25 to 50%

Correct Option: 3

Q.23 Internal characteristic of DC generator is a plot between the______and_____.

1. field current, terminal voltage
2. generated voltage, load current
3. terminal voltage, load current
4. field current, load current

Correct Option: 2

DDA JE Electrical ME 3 April 2023 Shift 1 Part 2

Q.24 Which method is used to prevent flashover in DC machines?

1. Resistance commutation
2. Compensating windings
3. Commutating poles
4. Brush shifting

Correct Option: 2

Q.25 In synchronous motor the air gap flux is due to:

1. load only
2. rotor current only
3. stator current only
4. stator current and rotor current both

Correct Option: 4

Q.26 A 4-pole wave wound armature has 360 conductors and is rotated at 500 rpm. If the useful flux is 40 mWb, calculate the generated emf.

1. 240 V
2. 120 V
3.960 V
4. 480 V

Correct Option: 1

DDA JE Electrical ME 3 April 2023 Shift 1 Part 2

Q.27 For PMMC type instrument, which of the following features is INCORRECT?

1. Low power consumption
2. Can be used for only DC
3. Scale is uniform
4. Torque to weight ratio is very low

Correct Option: 4

Q.28 For a 66 kV transmission line, how many discs are required in suspension type insulator?

1-8
2. 4
3. 2
4.6

Correct Option: 4

Q.29 The total inductance of two coils coupled in series aiding connection (cumulatively coupled) is 120 mH. If the same coils are connected differentially, then the total inductance is 20 mH. Find the mutual inductance.

1. 25 mH
2. 40 mH
3. 35 mH
4. 20 mH

Correct Option: 1

DDA JE Electrical ME 3 April 2023 Shift 1 Part 2

Q.30 Find the Q-factor of an RLC series circuit that will resonate at 4.5 kHz and has a bandwidth of 150 Hz.

1. 15
230
3. 60
4.45

Correct Option: 2

DDA JE Electrical ME 3 April 2023 Shift 1 Part 2

Q.31 Which parameter in a magnetic circuit is analogous to conductance in an electric circuit?

1. Flux
2. Reluctance
3. Permeance
4. mmf

Correct Option: 3

DDA JE Electrical ME 3 April 2023 Shift 1 Part 2

Q32. With reference to transmission efficiency of a transmission line, state whether the given statements are true or false. Statements:
1. Load current is inversely proportional to the load p.f.
2. Transmission efficiency of a line decreases with decrease in load p.f.

1. Statement 1 and 2 are both false
2. Statement 1 and 2 are both true
3. Statement 1 is true, but statement 2 is false
4. Statement 1 is false, but statement 2 is true

Correct Option: 2

Q.33 Find the energy stored in the inductor of 5 H if it carries a current of 4 A.

1. 40 J
2. 80 J
3. 20 J
4. 10 J

Correct Option: 1

Q.34 A three-phase induction motor has a supply frequency of 60 Hz and synchronous speed of 1800 rpm. Find the number of poles.

1.8
26
3. 4
4. 2

Correct Option: 3

DDA JE Electrical ME 3 April 2023 Shift 1 Part 2

Q.36 In a transmission line, the receiving end power is 200 kW. If the transmission efficiency is 80%, calculate the sending end power.

1. 200 kW
2. 225 kW
3. 160 kW
4. 250 kW

Correct Option: 4

DDA JE Electrical ME 3 April 2023 Shift 1 Part 2

Q37. With reference to comparison of synchronous motor and induction motor, state whether the given statements are true or false.
Statements:
1. Both motors are doubly excited machines.
2. For same rating and same output, induction motor is more efficient than synchronous motor.

1. Statement 1 and 2 are both false
2. Statement 1 is true, but statement 2 is false
3. Statement 1 is false, but statement 2 is true
4. Statement 1 and 2 are both true

Correct Option: 1

Q.38 An electric iron draws 3 A at 210 V. Find its resistance.

1.60 £2
2.800
3.70 £2
4.90 £

Correct Option: 3

DDA JE Electrical ME 3 April 2023 Shift 1 Part 2

Q.39 Overhead distribution system is better than underground distribution system only in terms of

1. possibility of fault occurrence
2. public safety
3. appearance
4. initial cost

Correct Option: 4

DDA JE Electrical ME 3 April 2023 Shift 1 Part 2