ABB ACS880 Firmware Manual page 330

330 Parameters
No. Name / Range /
Selection
25.8 Drooping rate
0.00 ... 100.00 %
25.9 Speed ctrl balancing
enable
Not selected
Selected
DI1
DI2
DI3
Description
Defines the droop rate in percent of the nominal motor
speed.
Drooping decreases the drive speed slightly 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.
The 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.
Speed decrease = Speed controller output × Drooping
× Nominal speed
Example: Speed controller output is 50 %, droop rate
is 1 %, nominal speed of the drive is 1500 rpm.
Speed decrease = 0.50 × 0.01 × 1500 rpm = 7.5 rpm.
Motor speed in
% of nominal
No drooping
100%
Drooping
Droop rate.
Selects the source for enabling/disabling speed
controller output balancing.
This function is used to generate a smooth, "bumpless"
transfer from a torque- or tension-controlled motor
back to being speed-controlled. When balancing is
enabled, the output of the speed controller is forced
to the value of 25.10 Speed ctrl balancing
Balancing is also possible in the ramp generator (see
parameter 23.26 Ramp out balancing
0 = Disabled
1 = Enabled
0
1
Digital input DI1 (10.2 DI delayed
Digital input DI2 (10.2 DI delayed
Digital input DI3 (10.2 DI delayed
25.08 Drooping rate
Speed controller
output / %
100%
ref.
enable).
status, bit 0).
status, bit 1).
status, bit 2).
Def / Type
FbEq 16b / 32b
- / real32
Drive load
100 = 1 % / 100 = 1 %
Not selected / uint32
0
1
2
3
4