| 摘要 |
PURPOSE:To prevent overload of a motor and slackening of a steel plate by comparing the rotating speed of a pinch roll with a preset speed to drive a pinch roll driving motor at a large gain when the difference is small and at a smaller gain as the difference becomes larger. CONSTITUTION:An output signal of a speed detector 6 provided on a pinch roller driving motor 5 is converted to a speed feedback signal 16 through F/V converter 9, and then a signal of deviation between the signal 16 and a speed set signal 11 is input to a speed controller 1, from which a current reference signal 13 is generated. At this time, the speed controller 1 is adapted to set resistances R1, R2, Ra-Rd and voltage Vc in such a manner that gain of an operational amplifer AM1 is large when the deviation signal 12 is within the low level small range and gain of an operational amplifier AM2 is small when an input signal is within the high level range. According to a speed reference signal of the speed controller 1, the motor 5 is controlled through a current controller 2, a thyristor and a striking device 3. |
