N3: Overexcitation Deceleration - YASKAWA T1000A Technical Manual

5.9 n: Special Adjustments
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.
n
n2-02, n2-03: Speed Feedback Detection Control (AFR) Time Constant 1, 2
Parameter n2-02 sets the time constant normally used by AFR.
Parameter n2-03 sets the time constant during Speed Search or regenerative operation.
No.
n2-02
n2-03
Note: Parameter n2-02 cannot be set higher than n2-03 or an oPE08 error will result.
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.
• Increase n2-03 if overvoltage occurs with high inertia loads at the end of acceleration or with sudden load changes.
• If setting n2-02 to a higher value, also increase C4-02 (Torque Compensation Delay Time Constant 1) proportionally.
• If setting n2-02 to a higher value, also increase C4-06 (Torque Compensation Delay Time Constant 2) proportionally.
u n3: Overexcitation Deceleration
n
Overexcitation Deceleration (induction motors)
Overexcitation Deceleration increases the flux during deceleration and allows shorter deceleration time settings without
the use of a braking resistor. Enabled by setting L3-04 to 4 or 5. See
Deceleration on page 220.
Notes on Overexcitation Deceleration
• As regenerative energy is mainly dissipated as heat in the motor, the motor temperature will rise if Overexcitation
Deceleration is applied frequently. In such cases, make sure the motor temperature does not exceed the maximum
allowable value or consider using a braking resistor option instead.
• During Overexcitation Deceleration 2, Hunting Prevention in V/f Control and torque limits in Open Loop Vector
Control are disabled.
• Do not use Overexcitation Deceleration in combination with a braking resistor option.
• 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
• Use parameters n3-13 through n3-23 for adjusting Overexcitation Deceleration.
• When repetitive or long Overexcitation Deceleration results in 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, C1-04,
C1-06, or C1-08). Make sure to set this time so that 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 in order to keep the DC bus voltage at the level set in 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. If
overvoltage occurs (ov), try increasing the deceleration time.
• When a Run command is entered during Overexcitation Deceleration, overexcitation operation is cancelled and the
drive will reaccelerate to the specified speed.
236
Name
Speed Feedback Detection Control (AFR) Gain
Name
Speed Feedback Detection Control (AFR) Time Constant 1
Speed Feedback Detection Control (AFR) Time Constant 2
L3-04: Stall Prevention Selection during
YASKAWA ELECTRIC SIEP C710616 30B YASKAWA AC Drive T1000A Technical Manual
Setting Range
0.00 to 10.00
Setting Range
0 to 2000 ms
0 to 2000 ms
Default
1.00
Default
50 ms
750 ms