ABB ACS550 Series, User Manual

Page: 136 / 310

136 ACS550 User’s Manual
Parameters
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
= 1.
• Set 2502
CRIT SPEED
1
LO
= 18 Hz.
• Set 2503
CRIT SPEED
1
HI
= 23 Hz.
• Set 2504
CRIT SPEED
2
LO
= 46 Hz.
• Set 2505
CRIT SPEED
2
HI
= 52 Hz.
2502 CRIT SPEED 1 LO
Sets the minimum limit for critical speed range 1.
• The value must be less than or equal to 2503
CRIT SPEED
1
HI
.
• Units are rpm, unless 9904
MOTOR CTRL MODE
= 3 (
SCALAR
:
FREQ
), then 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
CRIT SPEED
1
LO
.
• Units are rpm, unless 9904
MOTOR CTRL MODE
= 3 (
SCALAR
:
FREQ
), then units are Hz.
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.
52
46
23
18
f1L
18 f2L
46 f1H
23 f2H
52
f
output
f
REF
(Hz)