Energy characteristics and motors heating of the electric drive of a drilling rig rotor in the mode of unstable rotation of the bit

The objective of this work is to study the heating of the electric drive motor of the drilling rig rotor in the mode of non-uniform rotation of the bit. The studies of the motor heating are carried out as a result of computer modeling of the in-duction electric drive operation on the basis of a previously developed program supplemented by a subroutine for de-termining energy losses and a subroutine for calculating the heating temperature of an explosion-proof induction motor based on its thermal diagram, which make it possible to calculate the heating temperature of the main motor elements (frontal and slot parts of the stator winding, rotor, stator, housing) taking into account the changing electromechanical and technological modes of rotary drilling of a well. The results of computer modeling of rotary drilling showed that in the mode of unstable uneven rotation of the bit with a relatively low power on the motor shaft, increased time-fluctuating losses of electric power in the windings occur, leading to overheating of the motor. It is shown that the choice of the power of the electric motor of the rotor drive must be carried out taking into account possible modes of unstable rotation of the bit, the expediency of increasing the power of the rotor drive motor is substantiated not only from the standpoint of unification of electric drives of the main working mechanisms of the drilling rig, but also from the stand-point of the possibility of overheating of the electric motor in difficult modes of rotary drilling.