| 摘要 |
<p>PURPOSE:To enable approximately maximum rating operation, by obtaining root mean square of current level having highest influence on the heating of a motor and grasping/controlling the heating amount accurately thereby eliminating excessive loading of motor. CONSTITUTION:First and second RMS operating units 10a, 10b take in many instantaneous load current levels of upper and lower roll motors 5a, 5b for a predetermined time and operate root mean square values thereof, then the results are fed to a first operational amplifier 11. Current values of the upper and lower roll motors 5a, 5b are also fed to the first operational amplifier 11. The first operational amplifier 11 operates correction current outputs itc, ibc for the upper and lower roll motors 5a, 5b and feeds them respectively to current regulators 3a, 3b.</p> |
