This function is used e.g. when balanced load is
needed for mechanically connected motors or
dynamic speed drooping is needed because of
changing load.
E.g. if load drooping is set to 10 % for a motor with a
nominal frequency of 50 Hz and the motor is loaded
with nominal load (100 % of torque) the output
frequency is allowed to decrease 5 Hz from the
frequency reference.
9209
Load drooping
Pos. Description
1
Load drooping time
(ID656)
2 Actual speed [rpm]
3 Torque
P3.1.2.11 Under Volt. Control
This parameter allows the undervoltage controller to
be switched out of operation. This may be useful, for
example, if the mains supply voltage varies more than
-15 % and the application will not tolerate this
undervoltage. In this case, the regulator controls the
output frequency taking the supply fluctuations into
account.
P3.1.2.13 StatorVoltAdjust
This parameter will be automatically set
during the identification run. It is
recommended to make the identification
run, if possible. See parameter P3.1.3.4.
Stator voltage adjust parameter is used only when
Permanent magnet synchronous motor (PMS motor)
has been selected for parameter P3.1.2.2. This
parameter has no affect if Induction motor has been
selected. With an induction motor in use, the value
has been internally forced to 100 % and it cannot be
changed.
When the value of parameter P3.1.2.2 (Motor type)
parameter is changed to PMS Motor, the parameters
P3.1.4.2 (Field WeakngPnt) and P3.1.4.3 (Voltage at
FWP) will be automatically extended up to the limits
of the drive's full output voltage, retaining the defined
U/f-ratio. This internal extension is done to avoid
running the PMS motor in the field weakening area
because the PMS motor nominal voltage is typically
much lower than the full output voltage capability of
the drive.
PMS motor nominal voltage typically represents the
motor's back-EMF voltage at nominal frequency, but
depending on the motor manufacturer, it may
represent e.g. the stator voltage at nominal load.
This parameter gives an easy way to adjust the
drive's U/f curve near to the motor's back-EMF curve
without needing to change several U/f curve
parameters. The StatorVoltAdjust 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.
129
English (GB)
To Next Page
Loading...
