YASKAWA Varispeed G7 Series Instruction Manual page 351

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.
Adjust energy-saving control according to the following energy-saving adjustment flowchart (V/f control).
b8-06 (Search Operation Voltage Limiter) will automatically perform fine gain adjustments for variations in
motor characteristics after the energy-saving gain has been adjusted. First adjust the energy-saving gain with
the following energy-saving adjustment flowchart (V/f control).
Set the motor capacity to E2-11
(Motor Rated Output).
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-
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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).
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START
YES
Yaskawa standard motor?
in increments of 5% to 10% so that the output power is minimized.
END
Fig 6.68 Energy-saving Adjustment Flowchart (V/f Control)
NO
Set the motor capacity to E2-11
(Motor Rated Output).
Run the motor at the rated
frequency and load.
Adjust while changing b8-04 (Energy-saving Coefficient)
Is U1-03 (Output Current) within
the motor rated current?
YES
* Rated load:
If the motor rated load is not known,
adjust with the rated load for the applicable system.
Increase b8-04 (Energy-saving Coefficient)
in increments of 5% to 10%.
NO