User`s manual

78
Slip Compensation Function Chapter 6-6
6-6 Slip Compensation Function
The slip compensation function calculates the motor torque according to the
output current, and sets gain to compensate for output frequency. This
function is used to improve speed accuracy when operating with a load.
Note The default setting varies with the capacity of the Inverter model.
Set Values • Set the rated slip value of the motor in use.
• This parameter is used as a slip compensation constant.
• Calculate the rated motor slip value from the rated frequency (Hz) and
rpm on the motor nameplate by using the following formula.
Note The default setting varies with the capacity of the Inverter model.
Set Values • Set the motor current with no load in percentage based on the rated
motor current as 100%.
• Contact the motor manufacturer for the motor current with no load.
• This parameter is used as a slip compensation constant.
Note This parameter is disabled with the value set to 0.0.
Set Values • Set the parameter to 1.0 first and check the operation of the Inverter.
Then fine-tune the gain with 0.1-gain increments or decrements.
If the speed is lower than the target value, increase the set value.
If the speed is higher than the target value, decrease the set value.
Set Values • This parameter is used for the response adjustment of the slip
compensation function.
• The default setting does not need any changes in normal operation.
• Change the default setting in the following cases.
The motor vibrates: Set the value to a larger value.
The motor response is low: Set the value to a smaller value.
n64 Motor Rated Slip Changes during
operation
Yes
Setting
range
0.0 to 20.0 (Hz) Unit of
setting
0.1 Hz Default setting (see note)
n65 Motor No-load Current Changes during
operation
No
Setting
range
0 to 99 (%) Unit of
setting
1% Default setting (see note)
Rated slit value (Hz) = Rated frequency (Hz) –
Rated prm Number of poles
120
n66 Slip Compensation Gain Changes during
operation
Yes
Setting
range
0.0 to 2.5 Unit of
setting
0.1 Default setting 0.0
(see note)
n67 Slip Compensation Time Constant Changes during
operation
No
Setting
range
0.0 to 25.5 (s) Unit of
setting
0.1 s Default setting 2.0