Critical Speed - ABB ACS850 Firmware Manual

136 Parameters
No. Name/Value
24.04 Minimum torq ref
-1000.0 ... 0.0%
24.05 Load share
-8.000 ... 8.000
24.06 Torq ramp up
0.000 ... 60.000 s
24.07 Torq ramp down
0.000 ... 60.000 s
25

25 Critical speed

25.01 Crit speed sel
Disable
Enable
Description
Defines the minimum torque reference.
Minimum torque reference.
Scales the torque reference to a required level (torque
reference is multiplied by the selected value).
Torque reference scaling.
Defines the torque reference ramp-up time, i.e. the time for
the reference to increase from zero to the nominal motor
torque.
Torque reference ramp-up time.
Defines the torque reference ramp-down time, i.e. the time for
the reference to decrease from the nominal motor torque to
zero.
Torque reference ramp-down time.
Sets up critical speeds, or ranges of speeds, that are avoided
due to, for example, mechanical resonance problems.
Enables/disables the critical speeds function.
Example: A fan has vibrations in the range of 540 to 690 rpm
and 1380 to 1560 rpm. To make the drive to jump over the
vibration speed ranges:
• activate the critical speeds function,
• set the critical speed ranges as in the figure below.
Motor speed
(rpm)
1560
1380
690
540
1
2
3
4
Critical speeds are disabled.
Critical speeds are enabled.
Drive speed Drive speed
1 2 3 4
(rpm) (rpm)
Par. 25.02 = 540 rpm
Par. 25.03 = 690 rpm
Par. 25.04 = 1380 rpm
Par. 25.05 = 1590 rpm
FbEq
10 = 1%
1000 = 1
1000 = 1 s
1000 = 1 s
0
1