Multipoint V/f characteristic
The multipoint V/f characteristic is based on the linear V/f characteristic. An additional characteristic point enables the adaptation to applications with special torque properties.
Details
This characteristic shape is suitable for applications that require a higher torque at lower speeds. The additional characteristic point can be configured in such a way that a higher voltage is provided in the lower frequency range of the characteristic. Otherwise, the same limits apply for the Multipoint characteristic as for the linear characteristic.
Select V/f characteristic control with Multipoint characteristic:
1.
Motor control mode 0x2C00 (P300.00) = "V/f characteristic control (VFC open loop) [6]"
2.
V/f characteristic shape 0x2B00 (P302.00) = "Multipoint [2]"
Setting of the V/f characteristic:
–
Limiting factors for the V/f characteristic:
–
Rated mains voltage 0x2540:001 (P208.01)
–
Minimum frequency 0x2915 (P210.00)
–
Maximum frequency 0x2916 (P211.00)
–
The rated mains voltage is set as the base voltage 0x2B01:001 (P303.01). The rated mains voltage corresponds to the product key of the inverter . The base voltage is set to the rated motor voltage (motor nameplate specification).
–
The base frequency 0x2B01:002 (P303.02) is set to the rated motor frequency (motor nameplate data).
–
The additional characteristic point is defined based on the parameters 0x2B01:003 (P303.03) and 0x2B01:004 (P303.04).
Characteristic examples:
–
Graphic on the left: the base voltage is set equal to rated mains voltage.
–
Graphic on the right: the base voltage is set lower than the rated mains voltage.
Parameter