ABB ACS850 Firmware Manual page 133

No. Name/Value
23.13 SpeedErr win lo
0 ... 3000 rpm
23.14 Drooping rate
Speed decrease = Speed controller output × Drooping × Max. speed
Example: Speed controller output is 50%, droop rate is 1%, maximum speed of the drive is
1500 rpm.
Speed decrease = 0.50 × 0.01 × 1500 rpm = 7.5 rpm.
Motor speed in
% of nominal
100%
0.00 ... 100.00%
Description
Defines the lower boundary of the speed error window.
Depending on setting of parameter
this is either an absolute value or relative to speed reference.
Lower boundary of speed error window.
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, i.e. equal to the value of this parameter. The drooping
effect decreases linearly to zero along with the decreasing
load.
Droop rate can be used e.g. 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.
No drooping
Droop rate.
23.11 SpeedErr winFunc,
23.14 Drooping rate
Speed controller
output / %
100%
Parameters 133
FbEq
1 = 1 rpm
Drive load
100 = 1%