• Calculate the rated motor slip and set the value in Pr.245 to enable slip compensation.
Slip compensation is not performed when Pr.245 = "0 or 9999".
Synchronized speed at the time of base frequency - rated rotation speed
Rated slip =
• When the slip compensation is performed, the output frequency may become larger than the set frequency. Set Pr.1 Maximum
frequency higher than the set frequency.
• Slip compensation will be disabled in the following conditions:
Stall prevention (oL, OL) operation, regeneration avoidance operation, auto tuning
Parameters referred to
5.13.15 Speed smoothing control
The output current (torque) of the inverter sometimes becomes unstable due to vibration caused by mechanical resonance.
Such vibration can be suppressed by reducing fluctuation of the output current (torque) by changing the output frequency.
Control block diagram
• When vibration caused by mechanical resonance occurs, set 100% in Pr.653 Speed smoothing control, perform
operation at the frequency with the largest vibration, and check if the vibration is suppressed after few seconds.
• If the setting is not effective, gradually increase the value set in Pr.653 and repeat the operation to check the effect to
determine the most effective value (Pr.653).
• If the vibration increases by increasing the value in Pr.653, decrease the value in Pr.653 from 100% to check the effect.
• When the vibrational frequency at which mechanical resonance occurs (during fluctuation of torque, speed, or converter
output voltage) is measured using an instrument such as a tester, set 1/2 to 1 times of the vibrational frequency in Pr.654
Speed smoothing cutoff frequency. (Setting the resonance frequency range mitigates vibration more effectively.)
Synchronized speed at the time of base frequency
0 to 200%
0 to 120 Hz
Speed smoothing control
× 100 [%]
Check the effect by increasing and decreasing the value at around
Set the minimum frequency for the torque variation cycle.
Current for torque
5.13 (G) Control parameters