ABB ACH550-01 User Manual page 242

Group 25: CRITICAL SPEEDS
This group defines up to three critical speeds or ranges of
speeds that are to be avoided due, for example, to mechanical
resonance problems at certain speeds.
Code Description
2501 CRIT SPEED SEL
Sets the critical speeds function on or off. The critical speed function
avoids specific speed ranges.
0 = – Disables the critical speeds function.
OFF
1 = – Enables the critical speeds function.
ON
Example: To avoid speeds at which a fan system vibrates badly:
• Determine problem speed ranges. Assume they are found to be
18...23 Hz and 46...52 Hz.
• Set 2501
• Set 2502
• Set 2503
• Set 2504
• Set 2505
2502 CRIT SPEED 1 LO
Sets the minimum limit for critical speed range 1.
• The value must be less than or equal to 2503
• Units are rpm, unless 9904
which case units are Hz.
2503 CRIT SPEED 1 HI
Sets the maximum limit for critical speed range 1.
• The value must be greater than or equal to 2502
• Units are rpm, unless 9904
which case units are Hz.
230
= 1.
CRIT SPEED SEL
1 = 18 Hz.
CRIT SPEED LO
1 = 23 Hz.
CRIT SPEED HI
2 = 46 Hz.
CRIT SPEED LO
2 = 52 Hz.
CRIT SPEED HI
f
output
52
46
23
18
f f
1L 1H
18 23
ACH550 User's Manual
Range
0=OFF, 1=ON
f f
2L 2H
46 52
0...30000 rpm /
0...500 Hz
MOTOR CTRL MODE
0...30000 rpm /
0...500 Hz
MOTOR CTRL MODE
Parameter listing and descriptions
f (Hz)
REF
1 .
CRIT SPEED HI
= 3 ( :
SCALAR FREQ
1
CRIT SPEED LO
= 3 ( :
SCALAR FREQ
), in
.
), in