Group 25: Critical Speeds - ABB ACS550-01 User Manual

ACS550 User's Manual

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 = OFF – Disables the critical speeds function.
1 = ON – Enables the critical speeds function.
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
CRIT SPEED SEL
• Set 2502
CRIT SPEED
• Set 2503
CRIT SPEED
• Set 2504
CRIT SPEED
• Set 2505
CRIT SPEED
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
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
2504 CRIT SPEED 2 LO
Sets the minimum limit for critical speed range 2.
• See parameter 2502.
2505 CRIT SPEED 2 HI
Sets the maximum limit for critical speed range 2.
• See parameter 2503.
2506 CRIT SPEED 3 LO
Sets the minimum limit for critical speed range 3.
• See parameter 2502.
2507 CRIT SPEED 3 HI
Sets the maximum limit for critical speed range 3.
• See parameter 2503.
= 1.
1 = 18 Hz.
LO
1 = 23 Hz.
HI
2 = 46 Hz.
LO
2 = 52 Hz.
HI
CRIT SPEED
= 3 (
MOTOR CTRL MODE
= 3 (
MOTOR CTRL MODE
f
output
52
46
23
18
f1L
18
1 .
HI
), then units are Hz.
SCALAR CONTROL
1 .
CRIT SPEED LO
), then units are Hz.
SCALAR CONTROL
f
REF
f1H f2L f2H
23 46 52
Start-Up
79
(Hz)