YASKAWA A1000 Technical Manual page 286

5.8 L: Protection Functions

L3-17: Target DC Bus Voltage for Overvoltage Suppression and Stall Prevention
Sets the target DC bus voltage target level used by the overvoltage suppression function (L3-11 = 1), Intelligent Stall
Prevention during deceleration (L3-04 = 2).
No.
L3-17 Target DC Bus Voltage for Overvoltage Suppression and Stall Prevention
<1> Values are specific to 200 V class drives. Double the value for 400 V class drives.
<2> This value is initialized when E1-01 is changed.

L3-20: DC Bus Voltage Adjustment Gain
Determines the proportional gain used by overvoltage suppression (L3-11 = 1), Single Drive KEB 2 (L2-29 = 1), KEB
Ride Thru 2 (H1- = 7A or 7B) and Intelligent Stall Prevention during deceleration (L3-04 = 2) in order to control the
DC bus voltage.
No.
L3-20
Adjustment for Single Drive KEB 2 (L2-29 = 1) and Intelligent Stall Prevention During Deceleration
• Increase this setting slowly in steps of 0.1 if overvoltage or undervoltage occurs at the beginning of deceleration.
• If this setting is too high, then a fair amount of speed or torque ripple can result.
Adjustment for Overvoltage Suppression
• Increase this setting slowly in steps of 0.1 if overvoltage suppression is enabled (L3-11 = 1) and a sudden increase in a
regenerative load results in an overvoltage (ov) fault.
• If this setting is too high, excessive speed or torque ripple can result.

L3-21: Accel/Decel Rate Calculation Gain
Determines the proportional gain used by overvoltage suppression (L3-11 = 1), Single Drive KEB 2 (L2-29 = 1), and
Intelligent Stall Prevention during deceleration (L3-04 = 2) in order to calculate acceleration and deceleration rates.
No.
L3-21
<1> This value is reset to its default value when the control mode is changed (A1-02). The value shown here is for Open Loop Vector Control.
Adjustment for Single Drive KEB 2 (L2-29 = 1) and Intelligent Stall Prevention During Deceleration
• Reduce L3-21 in steps of 0.05 if there is a fairly large speed or current ripple.
• Small reductions of L3-21can also help solve problems with overvoltage and overcurrent.
• Decreasing this setting too much can result in a slow DC bus voltage control response and may also lengthen
deceleration times beyond optimal levels.
Adjustment for Overvoltage Suppression
• Increase this setting in steps of 0.1 if overvoltage occurs as a result of a regenerative load when overvoltage
suppression is enabled (L3-11 = 1).
• If there is a fairly large speed ripple when overvoltage suppression is enabled, then decrease L3-21 in steps of 0.05.

L3-22: Deceleration Time at Stall Prevention during Acceleration
Sets the brief deceleration time used when stalling occurs while accelerating a PM motor. When set to 0, this function is
disabled and the drive will decelerate at the selected deceleration time when stalling occurs.
The function is effective only in Open Loop Vector Control for PM motors and if parameter L3-01 is set to 1.
No.
L3-22
286
Name
Name
DC Bus Voltage Adjustment Gain
Name
Accel/Decel Rate Calculation Gain
Name
Deceleration Time at Stall Prevention During Acceleration
YASKAWA ELECTRIC SIEP C710616 27G YASKAWA AC Drive A1000 Technical Manual
Setting Range
150 to 400 Vdc 375 Vdc
<1>
Setting Range
0.00 to 5.00 Determined by A1-02
Setting Range
0.10 to 10.00
Setting Range
0.0 to 6000.0 s
Default
<1> <2>
Default
Default
<1>
Default
0.0 s