The air gap in a generator, defined as the space between the rotor and stator, is a critical factor that significantly influences electromagnetic induction and overall machine performance. The size and uniformity of the air gap affect magnetic flux distribution, electromotive force, losses, vibration, and noise characteristics. Any eccentricity or non-uniformity in the air gap can cause electromagnetic force imbalances, leading to increased mechanical vibrations and noise, which may reduce the machine’s lifespan. Therefore, optimal air gap design is essential for maximizing generation efficiency and ensuring durability. This requires precise control of the air gap dimensions and shape through detailed electromagnetic analysis and experimental validation. This study presents an electromagnetic force analysis conducted to optimize the air gap design of a 30 kW-class high-speed (15,000 rpm) AC generator. Based on both simulation results and experimental validation, the air gap was optimized to improve power generation efficiency and enhance product durability. As a result, a rational design and testing methodology for military AC generators is proposed.

Abstract
1. 서 론
2. 고장현상 및 원인분석
3. 개선방안 검토 및 적용
    3.1 역기전력 분석
    3.2 유한요소해석을 통한 공극 최적값 도출
    3.3 입증시험
4. 결 론
References

• 김종식(Defense Agency for Technology and Quality) | Kim Jongsik Corresponding author
• 김건태(Defense Agency for Technology and Quality) | KIM Keontae