9000X AF Drives User Manual
MN04001004E
For more information visit: www.eaton.com 6-7
June 2009
V/f- Curve Manual Tuning
When tuning the V/f — curve manually (not using identification run) the motor shaft must be
unloaded and the motor control mode set to frequency control (P1.6.1). The following
parameters are adjusted to tune the V/f curve:
Parameters
V/f ratio selection P1.6.3
Field weakening point P1.6.4
Voltage at field weakening point P1.6.5
V/f curve midpoint frequency P1.6.6
V/f curve midpoint voltage P1.6.7
Output voltage at zero frequency P1.6.8
When using a linear V/f curve with increased zero frequency voltage ensure that the motor
current does not increase too much between 3 – 7 Hz.
Tuning Steps
Set the motor nameplate values.
Nominal voltage of motor P1.1.6
Nominal frequency of motor P1.1.7
Nominal speed of motor P1.1.8
Nominal current of motor P1.1.9
Motor Power Factor (Cos Phi) P1.1.10
Run the motor unloaded at 2/3 rated speed using a frequency reference. Read the motor
current from the monitoring menu (V7.4) or use 9000XDrive for monitoring. This current is
the motor magnetizing current. This value should match a nameplate magnetizing current
value if given.
If the motor will only be run in closed loop, skip to section on closed loop vector control
tuning.
Change the V/f- curve ratio selection to programmable-mode = 2 (P1.6.3).
Run motor with zero frequency reference and increase motor zero point voltage (P1.6.8) until
motor current is approximately same as the motor magnetizing current. (If motor is only in
the low frequency area for short periods, it is possible to use up to 80% of rated current).
Set then the midpoint voltage (P1.6.7) to 1.4142*P1.6.8 ( * Zero Point Voltage) and
midpoint frequency (P1.6.6) to value P1.6.8/100%*P1.1.7. ([ZeroPoint Voltage/100%]*Nominal
frequency of motor.)
2
P1.6.7 2 * P1.6.8 P1.6.6
P1.6.8
100
----------------
* P1.1.7==
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