The optimum excitation-current control program modifies the basic variable-voltage control mode. This function monitors the motor current and modulates the output voltage boosting the induction motor efficiency in the low-torque region typical of fan and pump motor applications.
In addition, second-order deceleration torque patterns brings the output voltage below the level of fixed-torque patterns. This conserves energy by matching the motor output with the second-order deceleration loads typical of fans. Intelligent energy saving control is possible due to the microprocessor-based current monitor loop which tracks motor energy and minimizes the inverter output voltage. This function is suited to constant-speed operation and augments the benefits of second-order deceleration patterns.
Mitsubishi Electric Automation, Inc., 500 Corporate Woods Parkway, Vernon Hills, IL 60061. Tel: 847-478-2100; Fax: 847-478-2396.