| 摘要 |
PURPOSE:To prevent an overcurrent from flowing a thyristor which constructs a converter at the regenerative operation time by limiting an output command to low by detecting a power source voltage. CONSTITUTION:A voltage detector 26 for detecting an AC power source voltage and a minimum value selector 27 which inputs the voltage signal of the detector and the output command 12a of a speed control calculator 12, compares both and applies a signal of low level to a voltage control calculator 14 as a corrected output command. Thus, it prevents an overcurrent from flowing to a thyristor band of the regenerative side for forming a converter. |
