Parameter Adjustments
• When repetitive or long Overexcitation Deceleration causes motor overheat, lower the overexcitation gain (n3-13) and reduce
the overslip suppression current level (n3-21).
• During Overexcitation Deceleration (L3-04 = 4), the drive decelerates at the active deceleration time (C1-02, C1-04, C1-06,
or C1-08). Set this time so no overcurrent (oC) fault occurs.
• During Overexcitation Deceleration 2 (L3-04 = 5), the drive decelerates using the active deceleration time while adjusting
the deceleration rate to keep the DC bus voltage at the level set to L3-17. The actual stopping time will be longer or shorter
than the set deceleration time depending on the motor characteristics and the load inertia. Increase the deceleration time if
overcurrent (oC) occurs.
• Entering a Run command during Overexcitation Deceleration cancels overexcitation operation and the drive reaccelerates
to the specified speed.
n
n3-13: Overexcitation Deceleration Gain
Multiplies a gain to the V/f pattern output value during Overexcitation Deceleration to determine the level of overexcitation.
The drive returns to the normal V/f value after the motor has stopped or when it is accelerating to the frequency reference.
No.
Name
Setting Range
Default
n3-13
Overexcitation Deceleration Gain
1.00 to 2.00
1.10
The optimum setting for n3-13 depends on the motor flux saturation characteristics.
• Gradually increase the gain to 1.25 or 1.90 to improve the braking power of Overexcitation Deceleration.
• Lower n3-13 when flux saturation characteristics cause overcurrent. A high setting sometimes causes overcurrent (oC),
motor overload (oL1), or drive overload (oL2).
u
n5: Feed Forward Control
Enabling Feed Forward improves the responsiveness of the drive to speed reference changes in applications where a high
speed control proportional gain setting (ASR gain, C5-01, C5-03) would lead to problems with overshoot, undershoot, or
oscillation.
gives an example of overshoot reduction by Feed Forward. Parameters related to this function and
the function principle are illustrated in
. Feed Forward can only be used in CLV, CLV/PM, or AOLV/PM (A1-02
= 3, 6, or 7).
1050
Overshoot
Conventional Speed Control
Feed Forward Control
Time (s)
Motor Speed (r/min)
Motor Speed (r/min)
Time (s)
900
750
0
1050
900
750
0
0
0.5
1
0
0.5
1
Suppresses
overshoot at the
end of acceleration
Figure 5.103 Overshoot Suppression by Feed Forward Control
5.9 n: Special Adjustments
336
YASKAWA ELECTRIC SIEP C710636 04D U1000 Industrial MATRIX Drive Technical Manual
Summary of Contents for U1000 iQpump Drive
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