Coil diameter tracking system and tension regulation system using such tracking system

Claim 1

Apparatus for rolling material from a pay-off reel driven by a first motor drive to a rewind reel driven by a second motor drive, comprising: means for measuring the instantaneous diameter d X of one of said reels and for deriving a first signal representative of d X during the rolling operation; means for calculating the instantaneous diameter D X of the other of said reels in accordance with the formula: ##EQU19## where D 1 is the initial diameter of one of said reels and d 1 is the initial diameter of the other of said reels and for deriving a second signal representative of D X ; first means responsive to said first signal for controlling the motor drive associated with said one reel in relation to the ratio φ 1 /d X , where φ 1 is the flux of the motor drive associated with said one reel; second means responsive to said second signal for controlling the motor drive associated with said other reel in relation to the ratio φ 2 /D X , where φ 2 is the flux of the motor drive associated with said other reel; said first and second control means being controlled independently to provide desired tensions upon said pay-off and rewind reels, respectively.