ABB ACS 400 - Page 103

92 ACS 400 User’s Manual
Group 25: Critical Freq
In some mechanical systems, certain speed ranges can cause resonance problems. With this
parameter group, it is possible to set up to two different speed ranges that the ACS 400 will skip
over.
Example: A fan system vibrates badly from 18 Hz to 23 Hz and from 46 Hz to 52 Hz. Set the
parameters as follows:
CRIT FREQ 1 LO = 18 Hz and CRIT FREQ 1 HI = 23 Hz
CRIT FREQ 2 LO = 46 Hz and CRIT FREQ 2 HI = 52 Hz
Figure 32 Example of critical frequencies setting in a fan system with bad vibrations at frequency
ranges 18 Hz to 23 Hz and 46 Hz to 52 Hz.
Code Description
2501 CRIT FREQ SEL
Critical frequencies activation.
0 =
OFF
1 = ON
2502 CRIT FREQ 1 LO
Critical frequency 1 start.
Note! If LOW > HI, no critical frequency lock-out will happen.
2503 CRIT FREQ 1 HI
Critical frequency 1 end.
2504 CRIT FREQ 2 LO
Critical frequency 2 start.
2505 CRIT FREQ 2 HI
Critical frequency 2 end.
Note! If LOW > HI, no critical frequency lock-out will happen.
f
output
52
46
23
18
f
REF
(Hz)
f1L
18
f2L
46
f1H
23
f2H
52
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