his article offers two different strategies for three-phase induction motor (3IM) parameters estimation (3IMPE). These two proposed strategies are namely: (i) manufacturer's datasheet method (MDSM) and, (ii) on-service method (OsM). The OsM is addressed based on actual measurements without any need to disconnect the motor from the connected load. On top of this, the electrostatic discharge optimizer (ESDO) as a new meta-heuristic optimization approach is employed for 3IMPE as well. The best results of ESDO are validated by assessments compared to other recognized optimization methods such as genetic algorithm and water cycle algorithm. To examine the outcome of the ESDO for 3IMPE using the datasheet and OsM procedures, three 3IMs with different ratings (90 kW, 45 kW and 2.2 kW) are investigated with necessary validations. Two equivalent circuits to express the 3IM performance are used such as single-and double-cage models. At last, an additional experimental model is developed using 0.75 kW 3IM to validate the simulated and theoretical results. For sake of quantifiable results, the maximum biased actual error among the demonstrated model and measured results at various speeds is within +/- 1%, which confirms the accuracy degree for studied test cases including experimental setup. Sensitivity analysis of parameters is made using Sobol sensitivity indices. It can be confirmed that the proposed methodology complete with its associated strategies via comparisons, sensitivity analysis and experimental validations are effective and viable in estimating the 3IM parameters.