YASKAWA AC Drive-A1000 Technical Manual page 271

• Lower this setting if motor current is too high during HSB. High current can damage the motor due to overheat.
• The default setting is 150% when the drive is set for Heavy Duty, and 120% when the drive is set for Normal Duty.
No.
n3-02
n
n3-03: High Slip Braking Dwell Time at Stop
When the motor reaches a relatively low speed at the end of HSB, the output frequency is kept at the minimum output frequency
set to E1-09 for the time set to n3-03. Increase this time if the inertia is very high and the motor coasts after HSB is complete.
No.
n3-03
n n3-04: High Slip Braking Overload Time
Sets the time required for an HSB overload fault (oL7) to occur when the drive output frequency does not change during an
HSB stop due to excessive load inertia or the load rotating the motor. To protect the motor from overheat, the drive trips with
an oL7 fault if these conditions last longer than the time set in n3-04.
No.
n3-04
n Overexcitation Deceleration (induction motors)
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.
Notes on Overexcitation Deceleration
• Frequently applying Overexcitation Deceleration raises the motor temperature because regenerative energy is mainly
dissipated as heat in the motor. In cases where frequent application is required, make sure the motor temperature does not
exceed the maximum allowable value or consider using a braking resistor option in lieu of Overexcitation Deceleration.
• During Overexcitation Deceleration 2, Hunting Prevention in V/f Control and torque limits in OLV Control are disabled.
• Do not use Overexcitation Deceleration in combination with a braking resistor option.
• Overexcitation Deceleration can be used in OLV and CLV, but it lowers the accuracy of Torque Control and 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 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, C1-04, C1-06,
or C1-08). 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.
n3-13
The optimum setting for n3-13 depends on the motor flux saturation characteristics.
• Gradually increase the gain to 1.25 to 1.30 to improve the braking power of Overexcitation Deceleration.
YASKAWA ELECTRIC SIEP C710616 31B YASKAWA AC Drive – A1000 Technical Manual
Name
High Slip Braking Current Limit
Name
High Slip Braking Dwell Time at Stop
Name
High Slip Braking Overload Time
Refer to L3-04: Stall Prevention Selection during Deceleration on page
Name
Overexcitation Deceleration Gain
5.9 n: Special Adjustments
Setting Range
Determined by
100 to 200%
C6-01 and L8-38
Setting Range
0.0 to 10.0 s
Setting Range
30 to 1200 s
252.
Setting Range
1.00 to 1.40
Default
Default
1.0 s
Default
40 s
5
Default
1.10
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