anordning foer justering av spaenning hos flexibelt material vid upp - eller avlindning pao, i trumma eller spole.

摘要

The apparatus comprises a three phase induction motor (1) for turning the drum or spool (4) modified to have a high resistance rotor providing a torque speed characteristic of falling torque with increasing speed. The motor drive, and torque in either forward or reverse drive, is controlled by a pair of thyristor banks (14;15) selectively triggered for forward and reverse drive modes by error signals representative of variation in tension from the required value.