EXPERIMENTAL CHARACTERIZATION OF MULTI-STAGE SPUR GEARBOX DYNAMICS UNDER VARIABLE TORQUE LOADS

This study investigates the dynamic performance of a multi-stage spur gearbox designed with a theoretical reduction ratio of 100:1. The gearbox comprises six involute spur gears on four shafts and was tested under input torque loads from 2.5 Nm to 27 Nm. Rotational speeds and torques were measured using digital tachometers (1%) and strain gauge sensors (0.5%). Output RPM ranged from 25.079 to 40.281, with an average deviation of 3.1% from the theoretical ratio. Input power varied between 0.07 W and 1.10 W, while output power ranged from 0.047 W to 0.76 W. Overall efficiency was observed between 63.9% and 87.8%, depending on load and speed. Linear regression analysis confirmed strong correlations: R2 0.854 for input-output RPM and R2 0.960 for torque transmission. These results indicate that while kinematic performance remains stable, frictional and alignment losses increase under high-load conditions. The findings contribute valuable empirical data to support the design and optimization of high-reduction gear systems for applications requiring low-speed, high-torque operation with predictable dynamic behavior.