| 摘要 |
PURPOSE:To simultaneously satisfy a rapid responsive and a safety as a control system and to rapidly and safely reset to a speed set value in the case of varying a speed due to external disturbance, etc., by cooperating alteration of a control constant with an increase/decrease in a load of an inverter. CONSTITUTION:A PI regulator 1 has a proportional calculator having an operational amplifier OP1, its input resistor R1 and a feedback resistor R2, an integrating calculator, an adder ADD2 for forming an output sum of both the calculators, and a short-circuiting switch SW. An inverter 2 and an induction motor 3 to be speed-controlled by the inverter 2 constitutes a forward element of a speed control system. A speed detector 4 detects an actual speed N of a motor cooperated with the motor. A load current detector 5 receives a detected current Im of a current transformer CT for detecting the output current of the inverter and outputs an output signal K.Im proportional to the detected current. A CP is a voltage comparator for generating an output when the absolute value of a speed deviation becomes larger than a signal Nas. |
