Patent ID: 6186434
Filing Date: 2001-02-13
Classification: B65H

Abstract:
A tension apparatus comprising:a mechanical section having an electromagnetic brake driven by an exciting current to generate an output torque, said mechanical section applying a tension to a material in continuous form which is being wounded and stretched by the output torque of said electromagnetic brake;signal output means for repeatedly outputting a PWM (Pulse Width Modulation) signal having a duty ratio corresponding to an input tension instruction value before and after a predetermined stop period;smoothing means for smoothing the PWM signal from said signal output means;maximum value holding means for holding a maximum voltage value of the smoothed PWM signal;exciting current supply means for supplying an exciting current corresponding to the held maximum voltage value to said electromagnetic brake; andreset means for resetting holding operation of said maximum value holding means on the basis of a magnitude comparison result between a current tension instruction value and a previous tension instruction value.