ABB ACS880 Firmware Manual page 492

492 Parameters
No. Name/Value
97.02 Minimum switching
frequency
0.000 ... 24.000
kHz
97.03 Slip gain
0 ... 200%
97.04 Voltage reserve
- 4 ... 50%
97.05 Flux braking
Disabled
Moderate
Full
97.06 Flux reference
select
Zero
User flux reference
Description
Defines a minimum switching frequency reference. The
actual switching frequency will not fall below this limit under
any circumstances.
Notes:
• This is an expert level parameter and should not be
adjusted without appropriate skill.
• The drive has internal switching frequency limits that may
override the value entered here.
Minimum switching frequency.
Defines the slip gain which is used to improve the estimated
motor slip. 100% means full slip gain; 0% means no slip
gain. The default value is 100%. Other values can be used if
a static speed error is detected despite having the setting at
full slip gain.
Example (with nominal load and nominal slip of 40 rpm): A
1000 rpm constant speed reference is given to the drive.
Despite having full slip gain (= 100%), a manual tachometer
measurement from the motor axis gives a speed value of
998 rpm. The static speed error is 1000 rpm - 998 rpm = 2
rpm. To compensate the error, the slip gain should be
increased to 105% (2 rpm / 40 rpm = 5%).
Slip gain.
Defines the minimum allowed voltage reserve. When the
voltage reserve has decreased to the set value, the drive
enters the field weakening area.
Note: This is an expert level parameter and should not be
adjusted without appropriate skill.
If the intermediate circuit DC voltage U
voltage reserve is 5%, the rms value of the maximum output
voltage in steady-state operation is
0.95 × 550 V / sqrt(2) = 369 V
The dynamic performance of the motor control in the field
weakening area can be improved by increasing the voltage
reserve value, but the drive enters the field weakening area
earlier.
Voltage reserve.
Defines the level of flux braking power. (Other stopping and
braking modes can be configured in parameter group
Start/stop mode).
See section Flux braking
Note: This is an expert level parameter and should not be
adjusted without appropriate skill.
Flux braking is disabled.
Flux level is limited during the braking. Deceleration time is
longer compared to full braking.
Maximum braking power. Almost all available current is used
to convert the mechanical braking energy to thermal energy
in the motor.
Defines the source of flux reference.
Note: This is an expert level parameter and should not be
adjusted without appropriate skill.
None.
Parameter 97.07 User flux
= 550 V and the
dc
(page 102).
reference.
Def/FbEq16
1.500 kHz
1000 = 1 kHz
100%
1 = 1%
-2%
1 = 1%
Disabled
21
0
1
2
User flux
reference
0
1