| 摘要 |
PURPOSE:To perform an operation in a low frequency region and a quick adjustable-speed operation safely regardless of the state of load by adding manual torque boosting characteristics in which a voltage correction value is increased with the lowering of frequency. CONSTITUTION:A voltage/frequency regulator 13 outputs a first correction value K1(Im-I0) for correcting the voltage/frequency pattern of the regulator 13 in response to the magnitude of input currents. A voltage corrector 20 outputs a second correction value (a-K2f0) for correcting the voltage/frequency pattern in response to output frequency f0. The first and second correction values are added and arithmetically operated in an adder 14, the result is inputted to an adder 6 through an amplifier 19, and V0+{K1(Im-I0)+(a-K2f0)} is obtained in the adder 6, and inputted to a motor through an amplifier 7. Accordingly, the input currents of the motor in a low frequency region are increased, thus quickly elevating torque to rated torque or more. |
