ABB ACSM1 - Page 171

Parameters and firmware blocks
171
28.07 DROOPING RATE FW block: SPEED CONTROL (see above)
Defines the droop rate (in percent of the motor nominal speed). The drooping slightly decreases the
drive speed as the drive load increases. The actual speed decrease at a certain operating point
depends on the droop rate setting and the drive load (= torque reference / speed controller output). At
100% speed controller output, drooping is at its nominal level, ie, equal to the value of this parameter.
The drooping effect decreases linearly to zero along with the decreasing load.
Drooping rate can be used, eg, to adjust the load sharing in a Master/Follower application run by
several drives. In a Master/Follower application the motor shafts are coupled to each other.
The correct droop rate for a process must be found out case by case in practice.
0…100% Droop rate.
28.08 BAL REFERENCE FW block: SPEED CONTROL (see above)
Defines the reference used in the speed control output balancing, ie, an external value to be forced to
the output of the speed controller. In order to guarantee smooth operation during output balancing, the
speed controller D-part is disabled and the acceleration compensation term is set to zero.
The source for the balancing enable signal is selected by parameter 28.09 SPEEDCTRL BAL EN.
-1600…1600% Speed control output balancing reference.
28.09 SPEEDCTRL BAL EN FW block: SPEED CONTROL (see above)
Selects the source for the speed control output balancing enable signal. See parameter 28.08 BAL
REFERENCE. 1 = Enabled. 0 = Disabled.
Bit pointer: Group, index and bit
28.10 MIN TORQ SP CTRL FW block: SPEED CONTROL (see above)
Defines the minimum speed controller output torque.
-1600…1600% Minimum speed controller output torque.
28.11 MAX TORQ SP CTRL FW block: SPEED CONTROL (see above)
Defines the maximum speed controller output torque.
-1600…1600% Maximum speed controller output torque.
Drive
load
Speed controller
output / %
Motor speed (% of nominal)
100%
Speed decrease = Speed controller output × Drooping × Max. speed
Example: Speed controller output is 50%, drooping rate is 1%, maximum speed of the drive is 1500 rpm.
Speed decrease = 0.50 × 0.01 × 1500 rpm = 7.5 rpm.
100%
} 28.07 DROOPING RATE
No drooping
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