The issues related to the interaction of the drive motors of the main mechanisms of a quarry excavator in the process of the joint functioning of the main mechanisms during the excavation of rocks are considered. It is shown that the transformation of the operating parameters (speeds and forces) of the main mechanisms into the power parameters realized on the bucket occurs depending on the kinematic properties of the lever mechanism connecting the main mechanisms with the bucket. The dependences of the relations between the operating parameters of the main mechanisms and the power parameters realized on the bucket on the coordinates of the top of the cutting edge of the bucket are obtained. The assessment of the degree of counteraction of the motors of the drives of the main mechanisms in the process of excavation by the coefficient of excess energy consumption was carried out. The results of the work will make it possible to create a control system for the drives of the main mechanisms adapted to the operating conditions. The purpose of the study is to increase the efficiency of operation of quarry excavators.