Applying the synchronous reluctance motors allows increasing the energy efficiency of many industrial applications. The new standards define 5 classes of energy efficiency from the IE1 level to the IE5 level for electric motors. The article deals with the mathematical modelling issues and experimental study of magnet-free synchronous reluctance motor of ultra premium energy efficiency class IE5. The proposed mathematical model allows calculating the efficiency, the power factor, the torque ripple, the winding losses and other operating characteristics of the synchronous reluctance motor in various modes. The experimental studies by using specially developed test bench with the direct torque measurement were carried out. The thermocouples were used for measuring the winding temperature and its measurement was made in the steady state of temperature mode. The developed prototype of the synchronous reluctance motor is made in the frame of the same size and rotation axis height, as the serially produced induction motor of the same power was. The results of experimental comparison of the developed prototype of the magnet-free synchronous reluctance motor with energy efficiency class IE5 and serially produced synchronous reluctance motor with energy efficiency class IE4 are presented.