Perancangan Sistem Catu Daya Bertegangan Rendah Arus Besar Menggunakan MOT (Microwave Oven Transformers) pada Aplikasi Spot Welding

Abstract

This study aims to design and develop a high-current, low-voltage power supply system using a modified Microwave Oven Transformer (MOT) for spot welding applications. The system was designed by modifying the secondary winding of the MOT to reduce the output voltage and increase the output current, while also implementing a rectifier circuit and filter capacitors to produce a stable DC output. The research employed an experimental method with a quantitative approach, involving variations in current (30%–99%) and welding duration (10–50 ms) to observe their effects on electrical parameters (final current and voltage) as well as the strength of weld joints on Nickel Strip material. Test results showed that increasing the current led to higher output current and voltage. The optimal weld strength was achieved at 60%–80% current, with the welded joint capable of withstanding loads up to 8,000 grams. At the highest current (99%), the joint strength reached 16,000 grams but showed signs of failure due to overheating. In conclusion, the MOT-based power supply system was successfully developed to produce a stable high DC current suitable for spot welding. The system is considered feasible for light welding applications and small-scale industrial prototypes, with a recommendation to integrate a cooling mechanism to enhance its durability during extended operation.