Energy Efficiency and Power Transmission Analysis of a High-Ratio Gear Reduction System

This study presents the design and experimental performance evaluation of a custom-built high-ratio gear reduction system composed of four shafts and six spur gears. The gear arrangement consists of three transmission stages: 2:1 (Gear 1–2), 10:1 (Gear 3–4), and 5:1 (Gear 5–6), resulting in a total theoretical speed ratio of 1:100. The gears were manufactured with tooth counts ranging from 10 to 100 and diameters between 36 mm and 316 mm. The gearbox was tested under five different input conditions, with input rotational speeds ranging from 0.281 to 0.391 RPM and torque levels from 2.5 to 27 Nm applied at the driver shaft. RPM and torque were measured at all four shafts to evaluate transmission performance. The maximum recorded output speed at shaft 4 was 40.281 RPM, corresponding to an actual speed multiplication factor of approximately 103:1, which closely aligns with theoretical expectations. Power at each shaft was calculated using the equation P=τ⋅ω. Input power ranged from 0.07 W to 1.10 W, while output power varied from 0.047 W to 0.76 W. The system demonstrated efficiencies between 63.9% and 87.8%, with the highest efficiency observed at moderate torque inputs (6–23 Nm). Energy losses were primarily due to friction, backlash, and minor alignment deviations. The results confirm that the gearbox performs reliably and efficiently for high-ratio speed conversion applications. This configuration is suitable for systems requiring compact form, low input speed, and high output speed, such as laboratory instrumentation, automation mechanisms, or kinetic energy recovery setups.