Brushless excitation system of alternator.pptx

Brushless excitation system of alternator

1. Brushless Excitation System of an Alternator

2. Session Outcomes: Explain the working principle of the brushless excitation system in an alternator. Describe the key components of the brushless excitation system and their functions. Analyze the advantages of using a brushless excitation system over a conventional excitation system.

3. Introduction The brushless excitation system is a common type of excitation system used in large synchronous machines. A system that provides the necessary field current(DC ) to the rotor winding of an alternator Essential for voltage regulation & Control Q

4. TURBO GENERATOR EXCITATION SYSTEM

5. Main Components & Working Principle 1.Main Exciter : Generates AC power for the alternator rotor field winding. 3-phase generator with field on stator and armature on rotor. 2. Rotating Rectifier Assembly : Converts AC to DC for rotor excitation. Silicon diode bridge, mounted on shaft 3. Pilot Exciter : A small generator that excites the main exciter. It is 3-phase generator with permanent magnet field or poles on rotor and 3-phase armature winding on stator. 4. Automatic Voltage Regulator (AVR): Controls the output voltage by adjusting the excitation current.

6. Schematic diagram AC DC DC AC

7. PMG PMG cooling fan Main Exciter armature Rectifier wheel

8. Increased reliability due to the absence of brushes. Reduced maintenance costs. No risk of brush wear or sparking. Suitable for high-speed applications. Improved response to transient conditions. Power Generation: Used in hydro and thermal power stations. Marine Applications: Alternators in ships. Industrial Use: Large motors and alternators in industries. Advantages Applications

9. Conclusion The brushless excitation system is a crucial part of modern alternators due to its reliability and efficiency. It's widely used in large power generation systems, providing stable performance with minimal maintenance. Future developments may lead to even more advanced excitation systems.

10. Question   1. What is the primary role of the Pilot Exciter in the brushless excitation system? a) Generate AC for the main alternator b) Provide initial excitation for the main exciter c) Rectify AC to DC d) Regulate output voltage   2. In a brushless excitation system, what does the Rotating Diode Bridge Rectifier do?   a) Generates AC b) Converts AC to DC c) Controls the main exciter d) Regulates the pilot exciter  

11. 3. Which component directly excites the main alternator’s rotor in the brushless excitation system? a) Pilot exciter b) Main exciter c) Rotating rectifier d) AVR   4. What is the function of the Automatic Voltage Regulator (AVR) in the brushless excitation system? a) To generate AC voltage b) To rectify AC to DC c) To regulate the output voltage d) To provide mechanical support to the rotor   5. What is the benefit of using a brushless system in high-speed rotating machines? a) Higher friction losses b) Lower efficiency c) Increased reliability and lower maintenance d) Increased physical size

12. Thanks