SLX9000 Adjustable Frequency Drives User Manual
MN04003020E
For more information visit: www.eaton.com 9-21
January 2009
Motor Control
Figure 9-16: Linear and Squared Change of Motor Voltage
2.6.1 Motor control mode ID600
0 Frequency control: The I/O terminal and keypad references are
frequency references and the drive controls the output frequency
(output frequency resolution = 0.01 Hz).
1 Speed control: The I/O terminal and keypad references are speed
references and the drive controls the motor speed (accuracy ± 0.5%).
2.6.2 VHz ratio selection ID108
Linear: 0 The voltage of the motor changes linearly with the frequency in the
constant flux area from 0 Hz to the field weakening point where the
nominal voltage is supplied to the motor. Linear VHz ratio should be
used in constant torque applications. See Figure 9-16.
This default setting should be used if there is no special need for
another setting.
Squared: 1 The voltage of the motor changes following a squared curve form with
the frequency in the area from 0 Hz to the field weakening point where
the nominal voltage is also supplied to the motor. The motor runs under
magnetized below the field weakening point and produces less torque
and electromechanical noise. Squared VHz ratio can be used in
applications where torque demand of the load is proportional to the
square of the speed, e.g in centrifugal fans and pumps.
V
f [Hz]
Linear
Squared
Vn
ID603
Default: Nominal
Voltage of the Motor
Field Weakening
Point
Default: Nominal
Frequency of the
Motor
ID602
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