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    Ipq&f U5

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    Rohit kannojia
    Communication circuits are more sensitive to harmonics than power circuits or power transmission circuits. Harmonics can cause spurious tripping of protective relays and increase losses in transformer windings and motor windings. Harmonics are integer multiples of the fundamental frequency and produce waveform distortion. Harmonics can be eliminated by filters and their effects reduced by using fractional slot windings or skewed pole faces in machines.

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    Ipq&f U5

    Uploaded by

    Rohit kannojia
    3K views6 pages
    Communication circuits are more sensitive to harmonics than power circuits or power transmission circuits. Harmonics can cause spurious tripping of protective relays and increase losses in transformer windings and motor windings. Harmonics are integer multiples of the fundamental frequency and produce waveform distortion. Harmonics can be eliminated by filters and their effects reduced by using fractional slot windings or skewed pole faces in machines.

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    IPQ&F U5

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    Communication circuits are more sensitive to harmonics than power circuits or power transmission circuits. Harmonics can cause spurious tripping of protective relays and increase losses in transformer windings and motor windings. Harmonics are integer multiples of the fundamental frequency and produce waveform distortion. Harmonics can be eliminated by filters and their effects reduced by using fractional slot windings or skewed pole faces in machines.

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    3K views6 pages

    Ipq&f U5

    Uploaded by

    Rohit kannojia
    Communication circuits are more sensitive to harmonics than power circuits or power transmission circuits. Harmonics can cause spurious tripping of protective relays and increase losses in transformer windings and motor windings. Harmonics are integer multiples of the fundamental frequency and produce waveform distortion. Harmonics can be eliminated by filters and their effects reduced by using fractional slot windings or skewed pole faces in machines.

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    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
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    The passage discusses harmonics in power systems and their effects. Harmonics are sinusoidal voltages or currents that are integer multiples of the fundamental frequency and can cause issues like increased losses.

    Some sources of harmonics mentioned are arcing devices, heating devices, and ferromagnetic devices.

    Harmonics can be eliminated by introducing filters to provide a low impedance path for harmonic currents.

    1.

    Which of the following circuits will have more sensitivity towards Harmonics
    (A) Communication Circuits
    (B) Power Circuits
    (C) Power transmission circuits
    (D) None of these

    Answer
    Correct option is A

    2. Harmonics can cause spurious trip of the protective relays.


    (A) True
    (B) False

    Answer
    Correct option is A

    3. _________ are sinusoidal voltages or currents having frequencies that are


    integer multiples of the frequency.
    (A) Harmonics
    (B) Distortion
    (C) Notching
    (D) None of these

    Answer
    Correct option is A

    4. Which one of the following is waveform distortion:


    (A) DC offset
    (B) Electrical Noise
    (C) Notching
    (D) All of the above

    Answer
    Correct option is D

    5. Symmetrical waveforms will contain only ______ numbered harmonics.


    (A) Odd and Even both
    (B) Neither odd and even
    (C) Even only
    (D) Odd only

    Answer
    Correct option is D

    6. Harmonic Analyzer uses which of the following analysis to identify the


    predominate harmonic component.
    (A) Frequency domain analysis
    (B) Time domain analysis
    (C) Frequency-Time domain analysis
    (D) None of these

    Answer
    Correct option is A

    7. Because of the harmonics, conductor resistance will ____


    (A) Increase
    (B) Decrease
    (C) Remain same

    Answer
    Correct option is A
    8. Statement:- Harmonic voltages and currents will increase the losses in rotor
    winding and stator winding of motors.
    (A) True
    (B) False

    Answer
    Correct option is A

    9. Due to Harmonics in Transformer which of the following losses increases:


    (A) Hysteresis Loss only
    (B) Eddy Current Loss only
    (C) Both A & B
    (D) No losses will increase

    Answer
    Correct option is C

    10. When analysing a non sinusoidal waveform, it is important to know the ____
    of the harmonic components present.
    (A) Magnitude and Phase angle
    (B) Phase angle only
    (C) Magnitude only
    (D) firing angle only

    Answer
    Correct option is A

    11. Harmonics can be eliminated by introducing which of the following:


    (A) Resonant circuit
    (B) High Impedance
    (C) Filters
    (D) Low impedance path
    Answer
    Correct option is C

    12. Statement: Shielded cables and twisted pairs used more frequently in
    communication circuits to decrease the mutual coupling
    (A) True
    (B) False

    Answer
    Correct option is A

    13. Statement: When one or more harmonic components has added to the
    fundamental frequency, a non-distorted (non sinusoidal) waveform is produced.
    (A) True
    (B) False

    Answer
    Correct option is B

    14. When electrical transformer is energized, which of the following harmonic


    component is predominate:
    (A) Third Harmonic
    (B) Seventh Harmonic
    (C) Second Harmonic
    (D) Fifth Harmonic

    Answer
    Correct option is C
    15. Which of the following device is not the source of harmonics:
    (A) Arcing devices
    (B) Pure resistance loads
    (C) Heating devices
    (D) Ferromagnetic devices

    Answer
    Correct option is B

    16. Skin effect is observed in which of the circuits:


    (A) DC Circuits
    (B) AC Circuits
    (C) Both A and B
    (D) None of these

    Answer
    Correct option is B

    17. For reducing the slot harmonics in an alternator, the length of air gap is
    (A) Reduced
    (B) Increased
    (C) Remain same
    (D) None of the above

    Answer
    Correct option is B

    18. To decreased the harmonics from the voltage waveform, the suitable steps
    is/are
    (A) Skewing the pole face
    (B) Using distributed type of winding instead of concentrated type
    (C) Using fractional slot windings
    (D) All of the above

    Answer
    Correct option is D

    19. If x is the order of harmonic component, then the general expression for
    distribution factor is
    (A) xsin(β / 2m) / msin(β / 2x)
    (B) sin(xm β / 2) / msin (x β / 2)
    (C) sin(x β /m) / xmsin(m β / 2)
    (D) xmsin(β / 2) /sin(mx β)

    Answer
    Correct option is B

    20. The harmonics in rotating machines are generated due to


    (A) non-sinusoidal field form
    (B) slotting of the stator core
    (C) both (A) and (B) above
    (D) none of the above

    Answer
    Correct option is C

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