Improving The Operation Performance; Reducing The Motor Speed Fluctuation (Slip Compensation Function) - Omron VARISPEED L7 Manual

Improving the Operation Performance

Reducing the Motor Speed Fluctuation (Slip Compensation Function)

When the load is large, the motor slip also increases and the motor speed decreases. The slip compensation
function keeps the motor speed constant, regardless of changes in load. When the motor is operating at the
rated load, parameter E2-02 (Motor Rated Slip) × the slip compensation gain value in parameter C3-01 is
added to the output frequency. The function can be used in V/f control or Open Loop Vector control.
Related Parameters
Parameter
No.
C3-01 Slip compensation gain
C3-02 Slip compensation delay time
C3-03 Slip compensation limit
C3-04 Slip compensation during regeneration
C3-05 Output voltage limit operation selection
Adjusting Slip Compensation Gain (C3-01)
If C3-01 is set to 1.0, the slip compensation value at 100% load is equal to the rated slip set in parameter
E2-02.
If necessary (motor speed is too high or too low) adjust the slip compensation gain as follows:
1. With Open Loop Vector control set E2-02 (Motor Rated Slip) and E2-03 (Motor No-load Current). The
motor rated slip can be calculated using the values on the motor nameplate and the following formula:
slip (Hz) = Motor rated frequency (Hz)
The motor data can be set automatically using the autotuning function.
2. With V/f control set C3-01 to 1.0.
3. Apply a load and compare the speed reference and the actual motor speed during run with constant speed.
Adjust the slip compensation gain by 0.1 at a time. If the speed is less than the target value, increase the
slip compensation gain, if the speed is higher than the target value, reduce the slip compensation gain.
4. Setting C3-01 to 0.0 disables the slip compensation function.
Adjusting Slip Compensation Primary Delay Time Constant (C3-02)
The slip compensation delay time constant is set in ms. The setting value of C3-02 is 2000ms. Normally, there
is no need to change these settings. When the slip compensation responsiveness is low, lower the set value.
When the speed is unstable, increase the set value.
Factory
Name
Setting
1.0
2000 ms
200%
Rated motor speed (rpm)
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Control Methods
Change
during
V/f
Operation
Vector
Yes A
No A
No A
1 No -
0 No -
×
Number of motor poles
120
Open Closed
Closed
Loop Loop
Loop Vec-
Vector tor (PM)
A - -
A - -
A - -
A - -
A A -
6
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