| 摘要 |
PURPOSE:To smooth a change of field current corresponding to a change in diameter of a coil and to prevent transient fluctuation of tension of a coil material by providing a coil diameter generation circuit capable of smoothly changing the coil diameter from an initialized coil diameter to an arithmetic coil diameter. CONSTITUTION:Electric motors for driving an unwinding coil and a winding coil are provided with pulse generators 6, 7 for detecting the rotational frequency of each coil. Output pulse signals from the generators are input to a coil diameter generation circuit 31. The coil diameter generation circuit 31 comprises a coil diameter arithmetic circuit 32 for computing the coil diameter from the above both pulse signals, an initial coil diameter memory 33 for giving the coil diameter by actual measurement before operation of the coil diameter, and a coil diameter switch circuit 51 for gently changing the initial coil diameter of the memory 33 and the arithmetic coil diameter of the above arithmetic circuit 32 to be switched. In this arrangement, a difference of the coil diameters is gradually lessened to change from the initial coil diameter to the arithmetic coil diameter. |
