| 摘要 |
<p>PURPOSE:To turn on power source after controlling of revolutions and synchronously drive pair rolls by low-frequency-starting the other of separate synchronous motors. CONSTITUTION:The synchronous motor 11 of the lower roll is low-frequency- started by controlling a frequency converter 15. After the output frequency and voltage of the frequency converter 15 have coincided with the frequency and voltage of the power source, the output voltage of the frequency converter 15 is made once zero and the synchronous motor 11 of the lower roll is started. Next, the synchronous motor 10 of the upper roll is low-frequency-started and when its speed has become nearly 100%, the deviations between the relative angle positions of cross pins 6a, 7a are eliminated or kept within a permissible value by controlling the revolution of the synchronous motor 10 based on the detection signal of the deviations between the relative angle position of both cross pins 6a, l7a from relative angle deviation detecting device 14. Next, the voltage phase difference between the input and output sides of the frequency converter 15 is detected and the revolution of the synchronous motor 10 is controlled by this signal, whereby the voltage phase difference is eliminated and the upper and lower rolls 4, 5 are synchronously driven.</p> |
