Exam Question

### (a) Purpose of AVR in an Alternator (6 Marks)
The Automatic Voltage Regulator (AVR) is a crucial component in an alternator system, primarily designed to maintain a constant and stable output terminal voltage under varying load conditions, speed fluctuations, and temperature changes. Its purpose is multifaceted, ensuring the reliable and safe operation of the electrical power generation system.
Key purposes of an AVR include:
* **Voltage Regulation:** The primary function is to automatically regulate the alternator's output voltage within specified limits, typically ±0.5% to ±1% of the rated voltage. This is achieved by continuously monitoring the output voltage and adjusting the excitation current supplied to the main alternator's field windings. Without an AVR, changes in load (especially reactive load) or prime mover speed would cause significant voltage fluctuations, potentially damaging connected equipment or impairing their performance.