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Monday, May 16, 2011

Hydro Generator- Part 3


Out-puts from a Generator - Governors

  • Governor ensures frequency at a set value by increasing / decreasing the fuel input

    Two types of Governors :
    Pneumatic : Fuel flow is controlled by valve position control. Control Input : DC Voltage
          Electronic : Fuel flow is controlled by a total servo mechanism. Control input : DC Voltage pulses 
 
Out-puts from a Generator - Voltage
  • Voltage is induced in the stator winding
  •  Terminal voltage depends upon :
  1.   No. of conductors in series per winding
  2.   Speed at which magnetic field cuts the winding
  3.   Strength of the magnetic field
 Voltage Control
  • Nominal Voltage = 415 V, 11 kV 
  • Voltage can vary due to load fluctuations 
  • Terminal voltage is controlled by
varying the Strength of magnetic field
          = varying the current through the field coil
          = varying the voltage applied to the field coil (Exciter control)
 
Typical Exciter
 
Read more in coming posts...