| 摘要 |
<P>PROBLEM TO BE SOLVED: To estimate the rotational speed of a driving roll without using a speed sensor such as a PLG (pulse generator). <P>SOLUTION: An estimation apparatus for estimating the rotational speed of a hearth roll 10 which is rotated and driven by a motor 14 comprises a current transformer (CT) 30 for detecting a driving current supplied from a power converter 26 to the motor 14 during the rotation of the hearth roll 10, a high-pass filter (HPF) 32 for extracting cyclic fluctuation contained in the driving current detected by the transformer 30 as a high-frequency component, and a speed calculating section 34 for estimating the rotational speed of the driving roll on the basis of the cyclic fluctuation of the driving current which is detected. <P>COPYRIGHT: (C)2003,JPO |
