Equipment for use on a cross-winding machine comprising a speed evaluation apparatus cooperating with a winding unit of the cross-winding machine and incorporating electromagnetic pulse generator means and an electronic pulse space-evaluation circuit arrangement operatively coupled with the pulse generator means. The pulses generated by the pulse generator means are delivered to the electronic pulse space-evaluation circuit arrangement. The pulse space-evaluation circuit arrangement contains a circuit for generating sawtooth voltages, the amplitude of which is proportional to the spacing in time of each two successive pulses. This pulse space-evaluation circuit arrangement further contains circuit means operatively coupled with the circuit for generating sawtooth voltages, said circuit means generating a step-shaped output signal, the height of whose last step indicates the momentary rotational speed. There is further provided a yarn cleaning device having means for scanning the traveling yarn, a thickness measuring channel, and an adjustable length measuring channel, both said channels being operatively coupled to the output of the scanning means for generating yarn thickness and yarn defect length indicating signals, respectively. Circuit means are operatively coupled to the output of said evaluating means for adjusting the sensitivity of the adjustable length measuring channel.