6
-118
Adjusting Energy-saving Control
The method of adjustment during energy-saving control operations differs depending on the control method.
Refer to the following when making adjustments.
V/f Control
In V/f control method, the voltage for optimum motor efficiency is calculated and becomes the output voltage
reference.
•
b8-04 (Energy-saving Coefficient) is set at the factory for motor use applied to the Inverter. If the motor
capacity differs from the motor applied to the Inverter, set the motor capacity in E2-11 (Motor Rated Out-
put). Also, adjust the output voltage in steps of 5 until it reaches minimum. The larger the energy-saving
coefficient, the greater the output voltage.
•
To improve response when the load fluctuates, reduce the power detection filter time constant b8-05. If b8-
05 is set too small, however, motor rotations when the load is light may become unstable.
•
Motor efficiency varies due to temperature fluctuations and differences in motor characteristics. Conse-
quently, control motor efficiency online to optimize efficiency by causing minute variations in voltage
using the search operation. Constant b8-06 (Search Operation Voltage Limiter) controls the range that con-
trol the voltage using the search operation. For 200 V Class Inverters, set the range to 100%/200 V, and for
400 V Class Inverters, set the range to 100%/400 V. Set to 0 to disable the search operation.
Vector Control
In vector control method, control the slip frequency so that motor efficiency is maximized.
•
Taking the motor rated slip for the base frequency as optimum slip, calculate the optimum slip for motor
efficiency for each frequency. In vector control, be sure to perform autotuning, and set the motor rated slip.
•
If the motor performs hunting when using energy-saving control in vector control, reduce the set value in
b8-02 (Energy-saving Gain), or increase the set value in b8-03 (Energy-saving Filter Time Constant).
