The nominal voltage of the PM motor agrees to the back-EMF voltage of the motor at
nominal frequency. But in a different motor manufacturer, it can be equal to, for example,
the stator voltage at nominal load.
Stator Voltage Adjust helps you to adjust the U/f curve of the drive near the back-EMF curve.
It is not necessary to change the values of many U/f curve parameters.
The parameter P3.1.2.13 gives the output voltage of the drive in percentage of the nominal
voltage of the motor at the nominal frequency of the motor. Adjust the U/f curve of the drive
above the back-EMF curve of the motor. The motor current increases the more the U/f curve
is different from the back-EMF curve.
Field
Weakening
Point
Field Weakening
Point Voltage
Motor Nominal
Voltage
Motor Nominal
Frequency
Stator Voltage Adjust
back
-EMF
Zero Frequency
Voltage
(50..200%)
200%
100%
50%
f [Hz]
U [V]
Fig. 22: The stator voltage adjustment
P3.1.2.14 OVERMODULATION (ID 1515)
Use this parameter to disable the overmodulation of the AC drive.
Overmodulation maximises the output voltage of the drive, but increases the motor current
harmonics.
P3.1.2.15 STATOR RESISTANCE VOLTAGE DROP (ID 662)
Use this parameter to set the motor stator phase-resistance value (in star-connection
equivalent circuit). The resistance is essential for an accurate motor control.
The value is given as a percentage of voltage drop at nominal current.
NOTE!
The identification run sets a value for this parameter automatically. We
recommend that you make the identification run, if it is possible. You can make the
identification run with the parameter P3.1.2.4.
PARAMETER DESCRIPTIONS
VACON · 203
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