Support shaft for rotating sleeves, e.g. bobbin carriers on wrapping machine, has windings to produce magnetic field that induces braking action in sleeves

摘要

A shaft (1) carries a number of conducting or ferromagnetic, freely rotating sleeves (2a, 2b, 2c). It has windings (7) placed in grooves in order to produce a uniform magnetic field along its length (X). The windings can be connected to a direct current supply to give a constant magnetic field with an even number of poles, or an alternating current to give a rotating field. Independent claims are also included for the following: (1) The process of producing a constant magnetic field along the length of the shaft (1) to give an eddy current braking effect in the sleeves (2a, 2b, 2c); (2) Using a constant magnetic field to give a braking effect by hysteresis in the alternating magnetization of the sleeves. A rotating magnetic field can also be used to give a braking effect or even a positive drive effect.