During the experiment, the program PP203 was used to record the torque and rotational speed of the rotor. The parameters of the tested rotor designs were determined based on the data recorded with the program RB01. The data contained in the PP203 files were exported to Microsoft Excel, which calculated the average values of rotor torque and speed and the standard deviations of the analyzed values for the given time of operation. The average torque required to overcome grinding resistance was determined according to equation 5: