| 摘要 |
PURPOSE:To minimize the speed increase of pinch rolls right after the release of the tail end of a material from a rolling mill by limiting the output level of a speed control device to the added value of acceleration and deceleration current and friction current just before the release of the tail end of the material from the rolling mill until the lapse of the prescribed time. CONSTITUTION:All of switches SW1, SW2, SW3 make switching operation just before the release of the tail end of the material from the rolling mill. The deviation between a speed reference PREF and speed detection signal is applied to a speed control circuit 18 by such switching. On the other hand, the added value of the acceleration and deceleration current Ia and the friction current If is applied as the current reference IREF to the output end of the circuit 18 by which the level thereof is limited. A current control circuit 19 is a much higher response speed than the response speed of the circuit 18 and therefore the current minus control is executed by applying directly the current reference IREF to the input of the circuit 19. The current for the tension is thus instantaneously suppressed and the speed increase at the tail end of the material is suppressed. |
