We consider the problem of a thread tension when a thread is reeled off from weft thread accumulator and balloons, passes through a thread conductor and moves farther with a constant speed. We apply the laws of conservation of momentum and conservation of energy to a finite part of a thread with the aim to estimate its tension and show that such consideration leads to different results if to assume a case without energy dissipation. As it follows from a number of experimental results in this case a thread often moves by jerks and vibrates although a speed of its end, by which it is pulled, and other conditions are maintained constant. To stabilize the nature of reeling off a thread it is advisable to increase of friction to dissipate an excess of kinetic energy acquired by a thread during the process
