Term 3.txt

  1. What is the Auto-start Sequence of a generator
    • Penstock is full
    • Exciter CB closes
    • Brakes release
    • Cooling water valve opens
    • Lift pump starts
    • Gate Lock Solenoid and Governor Shut Down Solenoid will pick up
    • Wicket Gates open to breakaway position (30-40%)
    • No-Load Speed Solenoid picks up (changing gate limit to 15%)
    • Lift Pump shuts down
  2. What is the purpose of the Exciter
    To control the generators terminal voltage by regulating the strength of the magnetic field on the rotor
  3. What is the purpose of the Governor
    To control the speed of the generator by regulating the flow of water
  4. What is the purpose of the Thrust Bearing
    To support the weight of the rotor, shaft and turbine
  5. What is the purpose of the Guide Bearing
    To keep the shaft aligned to prevent rotor stator contact
  6. What is the purpose of the Lift Pump
    To apply high pressure oil to the thrust bearing on start up and shut down
  7. What is the purpose of the field CB
    To open in case of a fault in the exciter circuit
  8. What is cavitation
    When a rapid pressure change in liquid causes empty cavities to be created and quick implode
  9. Why is the tailrace level above the height of the turbine
    To ensure seals stay lubricated when the unit is not in use
Author
SMD
ID
353491
Card Set
Term 3.txt
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