Motor Current Limit; U/F Ratio; Principle Of Stator Voltage Adjustment - Vacon 100 Applications Manual

Vacon 100 Application
The Stator voltage adjust parameter defines the drive's output voltage in percent of the motor's
nominal voltage at the motor's nominal frequency.
The U/f curve of the drive is typically tuned slightly above the back-EMF curve of the motor. The
motor current increases the more the drive's U/f-curve differs from the motor's back-EMF -
curve.
U [V]
Field Weakening
Point Voltage
Motor Nominal
Voltage
Zero Frequency
Voltage
Figure 34. Principle of Stator voltage adjustment
P3.1.3.1 M
OTOR CURRENT LIMIT
This parameter determines the maximum motor current from the AC drive. The parameter
value range differs from size to size.
When the current limit is active the drive output frequency is decreased.
NOTE: This is not an overcurrent trip limit.
P3.1.4.1 U/
F RATIO
Selection
Selection name
number
0 Linear
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Stator Voltage Adjust
(50..200 %)
Field
Motor Nominal
Weakening
Frequency
Point
Table 112.
The voltage of the motor changes linearly as a function of output
frequency from zero frequency voltage ((P3.1.4.6) to the field
weakening point (FWP) voltage (P3.1.4.3) at FWP frequency
(P3.1.4.2) This default setting should be used if there is no special
need for another setting.
vacon • 158
9208.emf
Description
f [Hz]
3