Energy-saving V/f characteristic (VFC-Eco)
In the case of the energy-saving V/f characteristic control (VFC-Eco), the motor voltage of the inverter is ascertained based on a linear characteristic as a function of the rotary field frequency or the motor speed to be generated. In addition, the motor is always operated in the optimum efficiency range by means of a cosϕ control and the resulting voltage dip (reduction of copper losses in the asynchronous motor). This is useful for energy efficiency with applications such as conveyors, where the torque and energy requirements are high during acceleration, but lower as soon as the load reaches the stationary speed.
Details
Select energy-saving V/f characteristic control with linear characteristic:
1.
Motor control mode 0x2C00 (P300.00) = "V/f characteristic control (VFC open loop) [6]"
2.
V/f characteristic shape 0x2B00 (P302.00) = "Eco [3]"
Setting of the V/f characteristic:
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The limiting factors for the V/f characteristic are the rated mains voltage 0x2540:001 (P208.01), the minimum frequency 0x2915 (P210.00) and the maximum frequency 0x2916 (P211.00).
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The base voltage 0x2B01:001 (P303.01) is usually set to the rated motor voltage (motor nameplate data). The base voltage is preset to the rated mains voltage. This in turn is preset according to the product key of the inverter. 
Mains voltage
Mains voltage –
The base frequency 0x2B01:002 (P303.02) is usually set to the rated motor frequency (motor nameplate data).
Eco efficiency range:
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The Eco efficiency range (grey) is between the V/f-standard characteristic (black) and the V/f Eco characteristic (green).
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The V/f Eco characteristic (green) is defined by the operating point that results from the minimum voltage 0x2B0D:001 (P330.01) and the base frequency 0x2B01:002 (P303.02).
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The minimum voltage 0x2B0D:001 (P330.01) has to be set in percent with reference to the base voltage 0x2B01:001 (P303.01).
The actual output frequency can exceed the set maximum frequency if the gain for the slip compensation in 0x2B09:001 (P315.01) is set to a value higher than 0.
Parameter