Maximum efficiency of an induction machine operating in a wide range of speed and torque - part 2 (calculation, simulation and measurement results)

A set of equations usable to calculate directly the optimum slip frequency and line voltage of a 3phase squirrel-cage induction machine with respect to maximum efficiency was deduced in part 1 of this article. An operation in steady state at any requested speed and torque in a wide range is taken into consideration. The requested torque, speed and an extended mathematical model of the machine based on a Γ-network are the inputs of the calculation. The optimum slip frequency and line voltage are the outputs. The calculation results using the deduced analytical formulas are compared with practical measurement results and with a MATLAB simulation of the machine input power in this part 2 of the article.