Solved Paper Junior Engineer Electrical 2018 [Part-1] – HPSSC Hamirpur

Series – B

Post Code – 663

1. Substances having a permeability less than the permeability of free space, are known as

1. Ferromagnetic
2. Bi-polar
3. Paramagnetic
4. Diamagnetic

2. De-guassing is the process of

1. Removing gases from materials
2. Removal of magnetic impurities
3. De-magnetizing metallic parts
4. Hysteresis loss

3. Bohr magneton is unit of

1. Removing gases from materials
2. Removal of magnetic impurities
3. De-magnetizing metallic parts
4. Hysteresis loss

4. Two different isotopes of an element have different

1. Number of neutrons
2. Number of electrons
3. Atomic number
4. Number of protons

5. Which of the following material is commonly used for making magnetic recording tape?

1. Ferric oxide
2. Silicon iron
3. Iron Dust
4. Iron

6. What is the angle between the pole and stay?

1. 30°
2. 45°
3. 60°
4. 10°

7. How many earth connections are required for the motor frame as per the IE Rule-61?

1. One
2. Two separate and distinct
3. Three separate and distinct
4. All of these

8. How is the ballast resistance connected with the choke?

1. Parallel
2. Series
3. Can be connected in either way.
4. Both A and B

9. What is the specification of GI earth plate?

1. 60 cm *60 cm *3.5 mm
2. 60 cm *60 cm *6mm
3. 60 cm*60cm*1mm.
4. 60 cm *60 cm *5.2 mm

10. Which type of cable does not require bedding?

1. Paper insulated lead covered cables
2. PVC cables
3. Both (A) and (b)
4. None of these

11. What is the maximum distance between the two successive cleats?

1. 0.25 m
2. 0.5 m
3. 0.9 m
4. 1.25 m

12. Spot welding is used to weld metal pieces whose thickness

1. Should be greater than 12 mm
2. Lesser than 12 mm
3. Lies between 15 to 20 mm
4. Greater than 20 mm

13. A low-frequency supply is given to the single-phase AC system for track electrification because

1. It improves commutation
2. Increases efficiency
3. Improves power factor
4. All of these

14. Which among the following is mechanical braking?

1. Pneumatic braking
2. Plugging
3. Dynamic braking
4. Regenerative braking

15. Three phase induction motor is not suitable for traction purpose because

1. Low starting torque
2. High starting current
3. Constant speed operation
4. All of these

16. The normal voltage used in directional heating is

1. 5 kV
2. 15 kV
3. 33 kV
4. 66 kV

17. In an arc furnace, the choke is provided to

1. Improve power factor
2. Stabilize the arc
3. Reduce the surge severity
4. All of these

18. If rated dc voltage is applied instead of ac to the primary of transformer

1. Secondary of transformer will burn
2. Secondary voltage will be excessively high
3. There will be no secondary voltage
4. There will be no secondary voltage

19. A transformer with an output voltage of 4200 V is supplied at 230 V. if the secondary has 2100 turns. Calculate the no. of primary turns.

1. 115
2. 125
3. 135
4. 145

20. The hot resistance of the filament of a bulb is higher than the cold resisitance because the temperature coefficient of the filament is

1. Negative
2. Infinite
3. Zero
4. Positive

21. A single phase A.C. voltage source has 200 V rms and a system connected consumes an active power of 300 W. What is the reactive power consumed by the system if 2.5 A rms current is drawn?

1. 100 VAR
2. 200 VAR
3. 300 VAR
4. 400 VAR

22. Which of the following can produce maximum induced voltage?

1. 1 A DC current
2. 50 A DC current
3. 1 A,60 c/s AC current
4. 1A, 490 c/s AC current

23. In a series RLC circuit, if the frequency is less than the resonant frequency, then

1. Circuit is capacitive.
2. Circuit is inductive.
3. Circuit is resistive.
4. No effect.

24. The conductivity of a metal is determined by

1. The no. of valance electrons per atom.
2. The electrons concentration and mobility of the electrons.
3. Both (A) and (B)
4. None of these

25. A superconductor may be used for generating

1. Voltage
2. Pressure
3. Temperature
4. Magnetic field

26. Increase in percentage of carbon in carbon steel reduces

1. Resistivity
2. Coercive force
3. Permeability
4. Retentivity

27. The magnetic field required to reduce the residual magnetization to zero is called

1. Retentivity
2. Coercivity
3. Hysteresis
4. Saturation

28. A transformer transforms

1. Voltage
2. Current
3. Voltage and current
4. Frequency

29. In a power transformer, the core loss is 50 W at 40 Hz and 100 W at 60 Hz under the condition of same flux density in both cases. The core loss at 50 hz will be

1. 64 W
2. 73 W
3. 82 W
4. 91 W

30. In a transformer, the primary ampere turns are counter balanced by

1. Secondary ampere-turns
2. Primary Flux
3. Increase in mutual flux
4. Increase in secondary current

31. The voltage regulation of a transformer having 02% resistance and 05% reactance, at full load, 0.8 power factor lagging is

1. 6 %
2. -4.6%
3. -1.4%
4. 4%

32. A single phase transformer has a maximum efficiency of 90% at full load and unity power factor. Efficiency at half load at same power factor will be

1. 86.7%
2. 88.26%
3. 88.9%
4. 87.8%

33. Grain oriented laminated sheet steel in a transformer reduces

1. Copper loss
2. Eddy current loss
3. Hysteresis loss
4. None of these

34. The windings used in a 03 phase shell type transformer is ____ type.

1. Circular
2. Cylindrical
3. Sandwich
4. Rectangular

35. Two transformers when operating in parallel will share the load depending upon which of the followings?

1. Magnetizing current
2. Leakage reactance
3. Per unit impedance
4. Efficiency

36. Stray losses in an electrical machine are sum of

1. Iron and mechanical losses
2. Copper and Iron losses
3. Copper and mechanical losses
4. None of these

37. The teeth in an armature of a DC machine are sometimes skewed. This is done to reduce

1. Hysteresis loss
2. Copper loss
3. Eddy current loss
4. Vibrations

38. An 8 pole DC generator has a single wave wound armature containing 32 coils of 6 turns each. The flux per pole is 0.06 Wb. If the generator is running at 250 RPM, the induced armature voltage will be

1. 96 V
2. 192 V
3. 384 V
4. 768 V

39. In a DC machine, the no. of mechanical and electrical degrees will be same DC the no. of poles in the machine are

1. 4
2. 2
3. 8
4. 1

40. The output indicated on the name plate of any motor is always the

1. Gross power
2. Power drawn in kVA
3. Power drawn in kW
4. Output power to shaft

41. The efficiency of DC motor when developing maximum power will be about

1. 100%
2. 50%
3. Less than 50%
4. More than 50%

42. At 1200 RPM, the induced emf of a DC machine is 200 V. For an armature current of 15 A, the electromagnetic torque produced will be

1. 23.8 Nm
2. 238 Nm
3. 2000 Nm
4. 3000 Nm

43. The efficiency of a DC series machine cannot be determined by swinburne’s

1. A series motor has very high starting torque.
2. A series motor draws an excessive current from the supply mains on no load.
3. A series motor runs at dangerously high speed on no load.
4. All of these.

44. Three-phase alternators are invariably connected in Star so as to

1. Reduce the size of stator conductors used.
2. Increase the terminal voltage.
3. Reduce magnetic losses.
4. All of these

45. The armature reaction effect in a synchronous machine depends on

1. Load current
2. F. of the load
3. Speed of the machine
4. Both A and B

46. Synchronous motors generally have

1. Salient pole rotor
2. Smooth cylindrical rotor
3. Either salient pole or smooth cylindrical rotor
4. None of these

47. A 10 pole, 25 Hz alternator is directly coupled to and is driven by 60 Hz synchronous motor. What is the no. of poles for the synchronous motor?

1. 48
2. 12
3. 24
4. 16

48. Variation in DC excitation of a synchronous motor causes variations in

1. Speed of motor
2. Power factor
3. Armature current
4. Both armature current and P.F.

49. The phenomenon of oscillation of the rotor of a synchronous motor about its equilibrium position corresponding to new load on sudden throwing off or increase load is called

1. Swinging
2. Crawling
3. Hunting
4. None of these

50. A reluctance motor

1. Is a self-starting motor.
2. Runs at a constant speed
3. Needs no DC excitation for its rotor.
4. Starts as an induction motor and runs as a synchronous motor.

51. The rotor of a stepper motor has

1. No Winding
2. No Commutator
3. No Brushes
4. All of these

52. In an induction motor, if the air gap is increased, then

1. Its speed will reduce.
2. Its efficiency will reduce.
3. Its power factor will reduce.
4. Its breakdown torque will reduce.

53. The slip of a 400 V, 3 phase, 4 pole, 50 Hz machine running at 1440 rpm is

1. 6%
2. 5%
3. 4%
4. 3%

54. The frequency of rotor current at standstill is equal to

1. Zero
2. 2f
3. F
4. 3f

55. In a double cage induction motor, the inner cage has

1. High resistance and high leakage reactance.
2. High resistance and low leakage reactance.
3. Low resistance and high leakage reactance.
4. Low resistance and low leakage reactance.

Read next: ॥ Part-2 ॥ Part-3 ॥