Yaskawa AC Drive Z1000 AC Drive HVAC Fan - Manual (Page 125)

• Overexcitation Deceleration can be most efficiently used in a V/f Control.
• Overexcitation Deceleration cannot be used with PM motors.
Parameter Adjustments
• Use parameters n3-13 through n3-23 to adjust Overexcitation Deceleration.
• 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 1 (L3-04 = 4), the drive decelerates at the active deceleration time (C1-02 or C1-04).
Set this time so no overvoltage (ov) 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
overvoltage occurs (ov).
• 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 1.40 1.10
The optimum setting for n3-13 depends on the motor flux saturation characteristics.
• Gradually increase the gain to 1.25 or 1.30 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). Lowering n3-21 can also help remedy these problems.
n n3-21: High Slip Suppression Current Level
If the motor current exceeds the value set to n3-21 during Overexcitation Deceleration due to flux saturation, the drive
automatically reduces the overexcitation gain. Parameter n3-21 is set as a percentage of the drive rated current.
Set this parameter to a relatively low value to optimize deceleration. If overcurrent, oL1, or oL2 occur during Overexcitation
Deceleration, reduce the high slip suppression current level.
No. Name Setting Range Default
n3-21 High Slip Suppression Current Level 0 to 150% 100%
n n3-23: Overexcitation Operation Selection
Limits the Overexcitation Deceleration operation selected in parameter L3-04 to forward only or reverse only.
No. Name Setting Range Default
n3-23 Overexcitation Operation Selection 0 to 2 0
Setting 0: Overexcitation Operation as Selected in L3-04 in Forward and Reverse Direction
Setting 1: Overexcitation Operation as Selected in L3-04 in Forward Direction Only
Setting 2: Overexcitation Operation as Selected in L3-04 in Reverse Direction Only
u n8: PM Motor Control Tuning
These parameters adjust the control performance in the vector control modes for permanent magnet motors.
n n8-45: Speed Feedback Detection Control Gain (OLV/PM)
Sets the gain for internal speed feedback detection control. Although this parameter rarely needs to be changed, adjustment
may be necessary under the following conditions:
• Increase this setting if motor oscillation or hunting occurs.
• Decrease this setting in increments of 0.05 to decrease drive responsiveness.
1.9 n: Special Adjustments
YASKAWA ELECTRIC SIEP YAIZ1U 03A YASKAWA AC Drive – Z1000 Programming Manual 125
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Parameter Details