[IEEE 2017 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM) & 2017 Intl Aegean Conference on Electrical Machines and Power Electronics (ACEMP) - Brasov, Romania (2017.5.25-2017.5.27)] 2017 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM) & 2017 Intl Aegean Conference on Electrical Machines and Power Electronics (ACEMP) - Determination of frequencies and vibration modes for a three phase induction motor IE3 premium efficiency