excitation system for alternator

STUDY OF DIFFERENT TYPES OF EXCITATION

SYSTEM FOR ALTERNATOR

SANTU SUTRADHAR ROLL NO- 10201615071 ELECTRICAL ENGINEERING

SUBMITTED BY :

Power Point Representation on

KALYANI GOVT. ENGINEERING COLLEGEKALYANI : NADIA

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CONTENTS Alternator Excitation System Function Of Excitation System Types Of Excitation System Description Of Each Type Conclusion Reference

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ALTERNATOR

It Is An Electrical Machine Which Converts Mechanical Power Into Electrical Power By

The Principle Of Electro-magnetic Induction.

Alternators Are The Primary Source Of All The Electrical Energy We Consume And Also

The Largest Energy Converters. KGEC/EE 14/7/2016

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STATOR

ROTOR

3 PHASE SUPPLY

ALTERNATOR

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EXCITATION SYSTEMThe Process Of Creating And Strengthening The Magnetic Field Of The Alternator By Providing The Necessary Direct Current To The Field Winding Of The Alternator

THE DIRECT CURRENT IS SUPPLIED TO THE ROTOR BY A SEPARATE D.C. SOURCE, CALLED EXCITER.

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FUNCTION OF EXCITATION

Supply Direct Current To the Field Winding For Creating Magnetic Field

Control Voltage & Reactive Power

Perform Protective Function

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TYPES OF EXCITATION SYSTEM

1. DC Excitation System

2. AC Excitation System

3. Static Excitation System

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D.C. EXCITATION SYSTEMTWO SMALL D.C.GENERATORS ARE USED AS EXCITERS.

D C EXCITATION SYSTEM

It is the oldest of all. Due to various problem now a days it is not conventionally used for large alternators

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A.C. EXCITATION SYSTEMIt Consists Of A.C. Generator And Thyristor Rectifier

Bridge Directly Connected To The Alternator Shaft or driven by separate motor.IT IS OF TWO TYPES

1. BRUSHLESS EXCITATION SYSTEM

2. ROTATING THYRISTOR EXCITATION SYSTEM

Main exciter is separately excited

Main exciter is self excited

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BRUSHLESS EXCITATION SYSTEM Elimination of brush & slip rings Less maintenance Fast response time

Suitable For Higher Rating Alternator

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Schematic Diagram

D.C.

A.C.

A.C.D.C.

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ROTATING THYRISTOR EXCITATION SYSTEM

D.C. A.C.D.C.

A.C

.D.C .

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STATIC EXCITATION SYSTEMThere Is No Rotating Part In This Excitation System. So No Windage Loss & Small Size.

Suitable For Medium & High Capacity Alternator

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Circuit Diagram

A.C.

D.C.

A.C.

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CONCLUSION

Selection of excitation system depends on various factors Alternator Power Alternator Size Alternator Speed Maintenance Cost

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Theory & Performance of Electrical Machine by J.B. Gupta https://www.quora.com https://www.youtube.com https://www.eblogbd.com

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REFERENCES

THANK YOU

DEPARTMENT OF ELECTRICAL ENGINEERING

KGEC/EE 14/7/2016