TW 16

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TW 1617 Synchronous Machine

• Construction
• Principle
• Characteristics
• Selection criterias
• Equivalent circuit
• Calculation on the basis of equivalent circuit

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TW16.0-16.6 Components
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TW16.0-16.6 Components
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TW16.0-16.6 Components
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TW16.0-16.6 Components
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TW16.0-16.6 Components
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TW16.0-16.6 Components
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TW16.0-16.6 Components
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TW16.0-16.6 Components
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TW16.0-16.6 Components
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TW16.0-16.6 Components
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TW16.0-16.6 Components
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TW16.0-16.6 Components
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TW16.7 Size Factors

• Small machines lower efficiencies
• Big machines better efficiencies
• 1000MW generator almost 99!!!
• Think again of magnetics and scale rules
• Therefore rather one big machine than more
  smaller machines
• 1 efficiency thousands of per day in power
  plant!!!

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TW16.89 Principle

• Synchronous machine is uncommutated dc machine
  inside out
• Stator is equal to asynchronous motor stator
• Rotating field is therefor the same
• No slip, but elastic, magnetic coupling between
  rotor and revolving field

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TW16.89 Principle
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TW16.89 Principle
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TW16.89 Principle
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TW16.91011 Equivalent Circuit
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TW16.91011 Equivalent Circuit
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TW16.12-14 Machine under Load
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TW16.12-14 Machine under Load
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TW16.12-14 Machine under Load
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TW16.12-14 Machine under Load
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TW16.12-14 Machine under Load
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TW16.15 Synchronization

• 1) Generator frequency bus frequency
• 2) Generator voltage bus voltage
• 3) Phase generator phase bus
• 4) Phase sequence generator phase
• sequence bus

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TW16.15 Synchronization
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TW16.16-18 Infinite Bus

• Infinite bus is a power supply where frequency
  and amplitude are constant under all load
  conditions
• The public electricity grid is an infinite bus
  feeding power into it by an ac generator does not
  increase the frequency or voltage.

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TW16.16-18 Infinite Bus
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TW16.16-18 Infinite Bus
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TW16.19 Torque Angle Torque
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TW16.19 Torque Angle Torque
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TW16.20 Active Power
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TW16.23 Active Power
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TW16.20 Active Power
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TW16.21 Control Active Power

• More power only more torque
• More torque more fuel per cycle
• Synchronous machine on infinite bus so no speed
  variations!
• Speed variations only possible when machine in
  island mode

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TW16.22 Transient Reactance

• Sudden load changes give much lower synchronous
  reactance
• Steady state has the usual reactance
• Large machines need up to 10 secs to reach normal
  Xs after transients!
• Good for voltage regulation at transients
• Bad for circuit breakage high current

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TW16.24 Machine Efficiency

• Check Magnetics chapters again and the note about
  scaling laws!
• The bigger the machines, the higher the
  efficiency.
• 16.24 is an example of the explained scaling laws
  in the magnetics lectures.

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TW17 Synchronous Motors

• 17.0-17.1 Read

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TW17.23 Motor Start Up

• Squirrel cage winding
• Start up with external motor
• Pull in torque rotor synchronizes with stator
  field

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TW17.4-7 Motor Under Load
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TW17.4-7 Motor Under Load
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TW17.4-7 Motor Under Load
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TW17.4-7 Motor Under Load
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TW17.8 Reluctance Torque
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TW17.8 Reluctance Torque
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TW17.8 Reluctance Torque
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TW17.8 Reluctance Torque
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TW17.8 Reluctance Torque