The article presents a method for investigating the dependence of the energy consumption of a manipulator on its position relative to the working trajectory of the end-effector. The mathematical model is based on a system of two second-order Lagrange equations. It is formulated in terms of the variable position of the manipulator with respect to the desired trajectory. The predominant load is the forces and moments of inertia acting on the object of manipulation, the links and rotors of electric motors. Kinetic energy recuperation and losses in the actuators were not considered. The movement of the end-effector was set along a straight-line trajectory with the most common law: trapezoidal velocity profile. Formulas for calculating the instantaneous actuator powers are derived by multiplying both sides of the Lagrange equations by functions of the respective angular velocities. The energy consumption per cycle is calculated by integrating only the positive values of the power. The research demonstrated a high level of effectiveness in optimizing robot placement to reduce energy costs.