6
-28
Field weakening option
The field weakening function is used to reduce the output voltage to the motor when the following conditions
are matched:
•
The frequency reference is above the value set in d6-02.
•
Speed agree is matched.
•
A digital input (H1-01 to H1-05) is set to 63.
In this case the output voltage is set to the value programmed in parameter d6-01 as a percentage of the corre-
sponding value for this frequency in the V/f curve.
Related parameters
Advantage of the function
•
Reducing the output voltage in quadratic loads is a simple way to save energy.
•
Having better speed and torque stability at frequencies near or above motor rated frequency.
Decreasing the voltage means decreasing the maximum torque in the same percentage.
However if the voltage is decreased only during speed agree, then the rated torque can be kept during
acceleration and deceleration.
Param-
eter
Number
Name
Description
Setting
Range
Factory
Setting
Change
during
Opera-
tion
Access
Level
RS-422A/
485
Register
LCD
Display
d6-01
Field weaken-
ing level
Set the Inverter output voltage
when the field weakening com-
mand is input.
It is enabled when the field weak-
ening command is set for a multi-
function input.
Set the level as a percentage tak-
ing the voltage set in the V/f pat-
tern as 100%.
0 to
100
80%
No
A
2A0H
Field-Weak
Lvl
d6-02
Field fre-
quency
Set the lower limit in Hz of the
frequency range where field con-
trol is valid.
The field weakening command is
valid only at frequencies above
this setting and only when the
speed is in agreement with the
current speed reference.
0.0 to
120.0
0.0 Hz
No
A
2A1H
Field-Weak
Freq
H1-01
-
H1-05
Terminal sel
S3-S7
Multifunction Digital Inputs
0 to 77
No
A
400H
to
404H
