QUIZ - 7



  1. The standard voltage ratings of an electromagnetic relay are-
    • 110 V, 63.5 V(L-N)
      220 V, 110 V
      230 V, 154 V
      400 V, 231 V


  2. The main function of relay is-
    • Fault isolation
      Fault detection
      Fault protection
      All of the above


  3. The relay operating coil is energized by-
    • Steam engine
      Power transformer
      Instrument transformer
      None of the above


  4. Which one is correct-
    • 1 VA relay is more senstive than 5 VA relay
      1 VA relay is Less senstive than 5 VA relay
      1 VA relay is equally senstive than 5 VA relay
      None of the above


  5. An over current relay having a current setting of 125% is connected to CT of 400/5. The pick up value is-
    • 6.25 A
      10 A
      12.5 A
      15 A


  6. The pick up value of relay is 7.5 A and fault current in relay coil is 30 A. Its plug setting multiplier is-
    • 2 A
      4 A
      6 A
      8 A


  7. Induction relays are used with-
    • AC
      DC
      Both AC and DC
      None of the above


  8. In merz-price protection, the CT secondary of delta - star transformer is connected in-
    • Star- delta
      Delta-delta
      Star-star
      Delta- star


  9. The number of pilot wires required for protecting 3-phaes transmission line using transley system of protection is-
    • 6
      4
      3
      2

  10. The least expensive overcurrent protection for LV system is-
    • Isolation
      Fuse
      Oil CB
      Air CB