134 Functional description CG Drives & Automation 01-7491-01r0
Droop Speed [349]
Speed drooping reduces the speed in proportion to the
torque. This can be used for stationary load sharing between
motors connected to the same load. The droop speed is the
requested speed reduction at nominal torque. The droop
speed is expressed in percent of nominal speed. The value
needs to be tuned to the application. A good starting value is
5%. The ramp times in [33x] impact the dynamic behavior.
Speed [rpm] = Speed Ref [rpm] - Droop Speed [%] /
100 * Torque [%] / 100 * Nominal Speed [rpm]
11.3.6 Torques [350]
Menu with all parameters for torque settings.
Maximum Torque [351]
Sets the maximum motor torque (according to menu group
“Motor Data [220]”). This Maximum Torque operates as an
upper torque limit. A Speed Reference is always necessary to
run the motor.
IxR Compensation [352]
This function compensates for the drop in voltage over
different resistances such as (very) long motor cables, chokes
and motor stator by increasing the output voltage at a
constant frequency. IxR Compensation is most important at
low frequencies and is used to obtain a higher starting
torque. The maximum voltage increase is 25% of the
nominal output voltage. See Fig. 112.
Selecting “Automatic” will use the optimal value according
to the internal model of motor. “User-Defined” can be
selected when the start conditions of the application do not
change and a high starting torque is always required. A fixed
IxR Compensation value can be set in the menu [353].
349 Droop Speed
Default: 0% (means function is turned off)
Range: 0 - 20%
351 Max Torque
Default: 120% calculated from the motor data
Range: 0–400%
NOTE: The Max Torque parameter will limit the
maxmum output current of the AC drive following the
relation: 100% Tmot corresponds to 100% Imot.
The maximum possible setting for parameter 351 is
limited by Inom/Imot x 120%, but not higher than
400%.
NOTE: The motor temperature increases very quickly
due to extensive power losses.
352 IxR Comp
Default: Off
Off 0 Function disabled
Automatic 1 Automatic compensation
User Defined 2 User defined value in percent.
T
MOT
Nm()
P
MOT
kw()x9550
n
MOT
rpm()
------------------------------------------=
= 100%
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