VARIABLE VOLTAGE-VARIABLE FREQUENCY POWER SOURCE

摘要

PURPOSE:To prevent a motor from stepping out by detecting a main circuit current, and providing means for compensating a speed command by negatively feeding back a deviation to a reference signal of a speed command if the detected value is the compared value or higher. CONSTITUTION:A current feedback signal detected by a detector 14 and rectified by a rectifier 15 is fed to an automatic current regulator 11 and a comparator 16. The comparator 16 detects a deviation between the operation level set by a command terminal 17 and a feedback signal, and delivers its output to a speed regulator 18. The regulator 18 receives a speed command signal set by a speed command terminal 5, and a deviation signal from the comparator 15 to decrease the speed command signal proportional to the deviation, thereby reducing the current to prevent the motor from stepping out due to the current limiting function.