band function is compensated by dynamic feed addition with respect to height and length application_number US 8621406 A description fig1 schematically shows a side view of one half of an open end rotor spinning machine producing cross wound bobbins rotor spinning machines of this type have as known between their end frames not shown a large number of similar spinning stations 1 the components of which are driven by a single motor the spinning station 1 has an opening device 2 into which a fiber band 5 is introduced by means of the feed roller 4 the feed roller 4 is driven by a continuously adjustable feed motor 3 the fiber band 5 is fed to an opening roller 7 rotating in the housing 6 and driven by a single motor and which opens the fiber band 5 supplied into individual fibers 8 the separated fibers 8 arrive through the fiber guide channel 9 onto the conical slip face 10 of a spinning rotor and from there into the fiber collecting groove 12 from the fiber collecting groove 12 the spun yarn 16 is drawn through the fiber draw off tube 17 in the direction of the arrow 18 with the aid of a draw off mechanism 19 the spinning.