.AR Elect. MA/MB Main Gen. & Support (Welch's Highlighted Notes)

Question 1

Main Generator:

• Ratings
• Max Amp rating with no Isophase Cooling?
• Max time full load can be maintained if cooling lost?
• Max/Min MVARs?

Answer 1

Main Generator

• 24 KV, 60 Hz, 1800 rpm
• 1559 MVA at 0.9 lagging pf
• 22.8 – 25.2 kV (Generator Terminal Voltage band)
• 40,000 amps rating
• 23,000 amp rating with no isophase cooling
  
  • full load can be maintained for 30 min if cooling lost and have no permanent damage
• - 310 MVARs (max BUCK to minimize low voltage conditions on the buses)
• + 560 MVAR (max Boost Generator Limit)

Question 2

Main Generator:

• Stator windings cooled by…
• Rotor/rotating field/field strength determined by?…
• Rotor current…
• Collector Housing cooled by…

Answer 2

Main Generator

• Stator windings (cooled by H2 and SCW) send power through the 3 terminal bushings to the isophase bus.
• Rotor produces the rotating field. Field strength determined by DC current in rotor windings. (rotor cooled by H2)
• Rotor current comes from the collector rings / brushes. Rings put the DC current on the rotor windings. Brushes supply the power to the rings.
• Collector housing cooled by Chilled Water (WC).