GB1454110A - Tension control sinterable powder compositions - Google Patents

Abstract

1454110 Automatic control systems EATON CORP 19 Dec 1973 [21 Dec 1972] 58860/73 Heading G3N The tension of material being driven between a material source and a roll is varied with the radius of material on the roll, the radius being determined by a divider from measurements of the roll angular velocity and the material linear velocity. As shown, these velocities are sensed by tachometers 24, 22 respectively and the instantaneous roll radius calculated by divider 42. The divider output is fed through amplifier 72 to summer 54 which also receives signals to compensate for roll friction and inertia, derived respectively from the derivative of the material velocity and from the roll angular velocity. Upon starting, the summer also receives a signal from circuit 46 to overcome roll striction. Summer 54 controls the roll drive torque or current so that the tension varies in proportion to the instantaneous roll radius. At low speeds of the roll, as detected by circuit 74, which includes a monostable multi-vibrator, the output of the divider 42 is replaced by a fixed value, otherwise the quotient would become indeterminate. In the divider 42, also Fig. 3 (not shown) a capacitor (88) is charged from tachometer 22 according to the material linear velocity, and discharged by a switching transistor (98) at a frequency proportional to the output of tachometer 24 i.e. the roll angular velocity. The divider output, which is a sawtooth, is averaged by amplifier 72 to produce the roll radius signal. The system is used in a winder for web or filament material e.g. paper.