N3: Overexcitation Braking - YASKAWA U1000 Series Technical Manual

5.9 n: Special Adjustments
n2-01: Speed Feedback Detection Control (AFR) Gain

Sets the internal speed feedback detection control gain in the AFR.
No.
n2-01
Normally there is no need to adjust n2-01 from the default setting. Make adjustments in the following cases:
• If hunting occurs, increase the setting value in steps of 0.05 while checking the response.
• If response is low, decrease the setting value in steps of 0.05 while checking the response.
n2-02: Speed Feedback Detection Control (AFR) Time Constant 1

Parameter n2-02 sets the time constant normally used by AFR.
No.
n2-02
These parameters rarely need to be changed. Adjust settings only under the following conditions:
• If hunting occurs, increase n2-02. If response is low, decrease it.
• If setting n2-02 to a higher value, also increase C4-02 (Torque Compensation Primary Delay Time) proportionally.
 n3: Overexcitation Braking
Overexcitation Deceleration (Induction Motors)

Overexcitation Deceleration increases the flux during deceleration and allows shorter deceleration time settings. Enabled
by setting L3-04 to 4. See
Notes on Overexcitation Deceleration
• During Overexcitation Deceleration 2, Hunting Prevention in V/f Control and torque limits in Open Loop Vector
Control are disabled.
• Overexcitation Deceleration can be used in Open and Closed Loop Vector Control, but it lowers the accuracy of Torque
Control, and thereby the braking efficiency. It can be most efficiently used in a V/f Control.
• Overexcitation Deceleration cannot be used with PM motors.
Parameter Adjustments
• When repetitive or long Overexcitation Deceleration results in motor overheat, lower the overexcitation deceleration
gain (n3-13).
• During Overexcitation Deceleration (L3-04 = 4), the drive decelerates at the active deceleration time (C1-02, C1-04,
C1-06, or C1-08). Make sure to set this time so that no overcurrent (oC) fault occurs.
• When a Run command is entered during Overexcitation Deceleration, overexcitation operation is cancelled and the
drive will reaccelerate to the specified speed.
n3-13: Overexcitation Deceleration Gain

Multiplies a gain to the V/f pattern output value during Overexcitation Deceleration, thereby determining 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.
n3-13
The optimum setting for n3-13 depends on the motor flux saturation characteristics.
• Increase the gain gradually by 1.25 to 1.90 to improve the braking power of Overexcitation Deceleration.
• If flux saturation characteristics cause overcurrent, try lowering n3-13. A high setting sometimes causes overcurrent
(oC), motor overload (oL1), or overload (oL2).
282
Name
Speed Feedback Detection Control (AFR) Gain
Name
Speed Feedback Detection Control (AFR) Time Constant 1
L3-04: Stall Prevention Selection during Deceleration on page
Name
Overexcitation Deceleration Gain
Setting Range
0.00 to 10.00
Setting Range
Setting Range
YASKAWA ELECTRIC SIEP C710636 03A YASKAWA U1000 Technical Manual
Default
1.00
Default
0 to 2000 ms
266.
Default
1.00 to 2.00
50 ms
1.10