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Haryana Staff Selection Commission (HSSC) Junior Engineer (JE) Electrical 2018 Questions With YouTube Explanation & PDF Part Two
Question-26.What is the full form of HRC
(1) High Rupturing Capacity
(2) High Reset Capacity
(3) High Re-striking Capacity
(4) High Residual Capacity
Explanation-HRC stands for high rupturing capacity fuse,Which is used to protect the circuit in short circuit fault and over current condition.it is used in rating up-to 1250 .
Question-27.Which device protects the high voltage surges on the power system
(1) Circuit Breaker
(4) Lightning Arrester
Explanation-Circuit breaker is used to break the circuit under fault condition,Due to high voltages surges a very high amount of current flow in line then relay sense this surges and send trip signal to circuit breaker to break the circuit.
Question-28. Which one is not current collectors for overhead system
(1) Trolley Collector
(2) Cable Collector
(3) Bow Collector
(4) Pantograph Collector
Explanation-In overhead transmission line the current in the line is collected with the help of sliding contact collector mounted on the roof of the vehicle.These are three types
B) Bow collector
Question-29. Iµ is ___________ Component of current in case of transformer.
(2) Iron loss
(4) Active loss
Explanation-The no load current of the transformer is divided into two parts one is Iµ=Io Sin $ ,this is called as magnetizing component of no load current .this is responsible for production of flux in the core.
Other component is working component or core loss component Iw=Io Cos $
Question-30. In Scott connection ___________ is a transformer which has a 0.866 tap on winding
(1) Main transformer
(2) Auto transformer
(3) Teaser transformer
(4) Step-up transformer
Explanation-Scott connection is used to convert 3 phase into 2 phase,In its construction there are two transformer should be used first is main transformer and second is teaser transformer.Tapping is always tapped on teaser transformer on primary side and tapping is provided at 0289 Tp,0.5 Tp and 0.866 Tp.
Question-31. Which line separates stator and rotor copper losses in circle diagram of induction motor
(1) Output line
(2) Torque line
(3) Input line
(4) Power factor line
Explanation-Circle diagram use for induction motor performance analysis,In the circle diagram the total copper losses should be separated to stator copper losses by torque line.
Question-32. Which of the following method of induction motor is from stator side
(1) By changing the applied voltage
(2) By changing rheostat
(3) By injecting emf
(4) By cascading motors
Explanation-The speed control of induction motor from stator side is applied by
- Changing the applied voltage
- Adding rheostat in the stator circuit.
- Changing the stator no of pole
- V/f control method
Others rest speed control method is applied from rotor side like cascading control,rotor emf injecting method,adding external resistance of star connection in rotor side.
Question-33. Diversity factor is always
(3) greater than 1
(4) less than 1
Explanation-As we know that diversity factor is the ratio of sum of individual maximum demand to maximum simultaneous demand and here sum of individual maximum demand is always greater than simultaneous maximum demand because load is always connected on full load,so diversity factor is greater than 1.Diversity factor directly proportional to sum of individual maximum demand of the consumer.
Question-34.The average value of alternating current is given by
(1) 0.637 Imax
(2) 0.707 Imax
(3) 1.11 Imax
(4) 1.41 Imax
Explanation-The average value of Alternating current is 2 Im/π=0.637 Im. Average value is always calculated from half cycle of symmetrical wave and full cycle of asymmetrical wave.
Question-35.What is form factor
(1) Average value / RMS value
(2) Instantaneous value / Average value
(3) Average value / Peak value
(4) RMS value / Average value
Explanation-Form factor is defined as the ratio of RMS value to the average value.For full symmetrical sine wave rms value is 0.707 Vm And average value is 0.637 Vm,So form factor is 0.707/0.637=1.11
Question-36. Low resistances are provided with four terminals
(1) To facilitate the connection of current and potential circuits
(2) In order that the resistance value becomes definite irrespective of nature of constants at the current terminals.
(3) To eliminate the effect of thermo-electric emfs.
(4) To eliminate the effect leads
Explanation-By using four terminal here two terminal is used for current measurement and other two terminal is used for voltage measurement and its constant value is definite.
Question-37. An alternator is a machine which converts ________ into ________.
(1) Electrical energy, Heat energy
(2) Mechanical energy, Heat energy
(3) Mechanical energy, Electrical energy
(4) Heat energy, Chemical energy
Explanation-An alternator is a device which is coupled with turbine and it convert mechanical energy into electrical energy
Question-38. The liveable area of a building at any floor is called
(1) built-up area
(2) carpet area
(3) super built-up area
(4) floor area
Explanation-Any person or liveable thing lived on ground floor of the area which is know as carpet area.
Question-39. Which metal rods are used as control rods in Nuclear power station
Explanation-Cadmium and boron rod is used as a controlling rod in nuclear power station.Which works to absorb neutron and control the chain reaction.
Question-40. What is the Voltage Value for High Voltage Substation
(1) Above 400 kV
(2) 132 kV to 400 kV
(3) 66 kV to 232 kV
(4) 11 kV to 66 kV
Explanation-The voltage value of high voltage substation is 11 kv to 66 kv.
Question-41. Dynamic response consists of
(1) two parts, one steady state and the other transient state response
(2) only transient state response
(3) only steady state response
(4) steady state and transient frequency response
Explanation-Dynamic response is a response which value changes with time or due to other factor.It is consist of two parts
1.steady state response 2.transient state response
Question-42. The material of wires used for making resistance standards is usually
(4) Phosphor Bronze
Explanation-Manganin has zero temp coefficient i.e doesn’t change their characteristic due to change in temperature effect,so it is used for making resistance.
Question-43. Potier triangle is required to calculate voltage regulation in which of the following method
(1) Synchronous impedance method
(2) Ampere-turn method
(3) MMF method
(4) ZPF method
Explanation-Voltage regulation can be calculated by using four method
A)synchronous impedance method or pessimistic method
B)emf method or pessimistic method
C)zero pf method or potier triangle
Potier triangle method is also known as zero power factor method ,which is used to measure accurate value of voltage regulation.
Question-44. __________ is the torque developed by the motor when full voltage is applied to its stator winding.
(1) Starting torque
(2) Running torque
(3) Pull-in torque
(4) Pull-out torque
Explanation-When we supply full voltage to its stator winding then torque developed by induction motor is starting torque.As we know starting torque is directly proportional to V2 .
Question-45. In second quadrant converter, the load current flows ________ the load. The load voltage is ________ And Load current is ________
(1) out of, positive, positive
(2) out of, positive, negative
(3) into, positive, positive
(4) into, positive, negative
Explanation-In second quadrant converter, the load current flows out of the load. The load voltage is positive And Load current is negative.
Question-46. A chopper converts
(1) DC fixed to DC variable
(2) AC to AC
(3) AC to DC
(4) 1-phase ac to 3-phase ac
Explanation-Chopper is a device which convert a fixed dc into variable dc output or desired dc output voltage.
Question-47. Duty cycle is ratio of __________ in case of chopper.
(1) Turn on to Turn off time
(2) Turn off to Total time
(3) Total time to Turn off time
(4) Turn on to Total time
Explanation-Duty cycle of chopper is the ratio of turn on to total time
Question-48. In 8085 microprocessor, the RST6 instruction transfer programme execution to following location
Explanation-In 8085 microprocessor, the RST6 instruction transfer programme execution in 0030H.
Question-49. Transistor-Transistor Logic (TTL) is a class of digital circuits built from
(1) Transistors only
(4) BJT & Resistors
Explanation-TTL stand for Transistor –Transistor Logic family.This class of digital circuit built of BJT and resistors
Question-50. Maxwell’s Inductance-Capacitance bridge is used for measurement of inductance of
(1) Low Q-coils
(2) Medium Q-coils
(3) High Q-coils
(4) Low and High Q-coils
Explanation-There are different types of inductance measurement bridge
A)Anderson bridge (used for low Q-coils measurement)
B)Maxwell bridge (used for medium Q-coils measurement)
C)Hay’s bridge (used for high Q-coils measurement)