EE1 PEEE Refresher Class Power Part 3 notes by T. Ernst EE1 – Power Part 3 NotesFall 2011, Page 1

EE1PEEE Refresher Class

Power Part 3

notes by T. Ernst

EE1 – Power Part 3 Notes Fall 2011, Page 1

Fall 2011, Page 2

EE1 – Power Part 3 Notes

• Induction Machines• Motors• Generators

• Synchronous Machines• Motors• Generators

• Double fed induction (variable speed synchronous)

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EE1 – Power Part 3 Notes

Induction Motors•Squirrel cage

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EE1 – Power Part 3 Notes

Only generate torque when slip is not equal to 0•Slip frequency [hz]•Slip speed [RPM]

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EE1 – Power Part 3 Notes

Synchronous speed f(frequency & poles)

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EE1 – Power Part 3 Notes

What is the difference between a motor and a generator?•Slip?•Power transfer?

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EE1 – Power Part 3 Notes

Induction motor nameplate

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EE1 – Power Part 3 Notes

Induction motor nameplate

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EE1 – Power Part 3 Notes

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EE1 – Power Part 3 Notes

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EE1 – Power Part 3 Notes

Locked rotor current example: 250 HP, code F

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EE1 – Power Part 3 Notes

Locked rotor equivalent impedance

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EE1 – Power Part 3 Notes

If FL (250 HP) speed is 3450 RPM, what is speed at 200 HP?

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EE1 – Power Part 3 Notes

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EE1 – Power Part 3 Notes

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EE1 – Power Part 3 Notes

Reduced Voltage Starting•Auto-transformer•Series inductor

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EE1 – Power Part 3 Notes

Reduced Voltage Starting• ½ - ½ • Wye start – delta run