Mitsubishi Electric FR-D720S SC EC, Instruction Manual

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Motor noise, EMI measures, mechanical resonance Parameter
6 - 146
6.14.2 Speed smoothing control (Pr. 653)
Vibration due to mechanical resonance influences the inverter control, causing the output cur-
rent (torque) unstable. In this case, the output current (torque) fluctuation can be reduced to
ease vibration by changing the output frequency.
The above parameter can be set when Pr. 160 = 0.
Control block diagram
Setting method
If vibration due to mechanical resonance occurs, set 100% in Pr. 653, run the inverter at the fre-
quency which generates maximum vibration and check if the vibration will be reduced or not af-
ter several seconds.
If effect is not produced, gradually increase the Pr. 653 setting and check the effect repeatedly
until the most effective value is set in Pr. 653.
If vibration becomes large by increasing the Pr. 653 setting, gradually decrease the Pr. 653 set-
ting than 100% to check the effect in a similar manner.
Pr.
No.
Name
Initial
Value
Setting
Range
Description Parameters referred to
Refer to
Section
653
Speed smoothing control 0 0–200%
Increase or decrease the value using
100% as reference to check an effect.
—
I001816E
Fig. 6-78: Control block diagram of the speed smoothing control
NOTE
Depending on the machine, vibration may not be reduced enough or an effect may not be
produced.
Output frequency
Speed
command
Torque current
Frequency output
Voltage output
V/f control
Speed smoothing control
Pr. 653
Acceleration/
deceleration processing