ABSTRACT
This chapter presents some basic equations for rotor-spun yarn production on a rotor spinning machine. It discusses the back-doubling phenomenon inside the rotor of rotor spinning machines. There is a draft between the lower ends of the doffing tube, that is, the navel and the collection surface of the rotor. The value of such a draft is lower than unity and is therefore called condensation and will be defined as follows. Condensation is very necessary to form or build up the rotor yarn layers of collecting surface fibers, that is, the successive layers of the fibers during their collection or condensation will generate the whole yarn body at the peeling-off point. The partial drafts or draft distribution between every two neighboring parts is the ratio between the bigger linear speed and the smaller linear speed, or can be calculated using the tex distribution of fiber flux distribution.
