YASKAWA GA700 Series Technical Manual page 887

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Overvoltage Suppression Function
Decreases the regenerative torque limit and increases the output frequency when the DC bus voltage increases to
prevent ov. This function can drive loads with cyclic regenerative operation, for example punch presses or other
applications with repeated crank movements. When you use this function, set L3-11 = 1 [Overvoltage Suppression
Select = Enabled].
The drive adjusts the regenerative torque limit and the output frequency during overvoltage suppression to make
sure that the DC bus voltage is not more than the level set in L3-17 [DC Bus Regulation Level].
Set these parameters as necessary when you use the overvoltage suppression function:
• L3-20 [DC Bus Voltage Adjustment Gain]
• L3-21 [OVSuppression Accel/Decel P Gain]
• L3-24 [Motor Accel Time @ Rated Torque]
• L3-25 [Load Inertia Ratio]
Note:
• When overvoltage suppression is triggered, the motor speed is more than the frequency reference. Do not use overvoltage suppression
for applications where the frequency reference and the motor speed must align.
• When you use a braking resistor, set L3-11 = 0 [Disabled].
• The overvoltage suppression function is enabled only when you operate immediately below the maximum frequency. Overvoltage
suppression does not increase the output frequency to more than the maximum frequency. Make sure that the motor and machine
specifications are correct for the application, then increase the maximum frequency.
• If there is a sudden increase to a regenerative load, ov can occur.
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L3-01: Stall Prevention during Accel
No.
Name
(Hex.)
L3-01 Stall Prevention during
Accel
(048F)
Note:
When A1-02 = 5 [Control Method Selection = OLV/PM], the setting range is 0 and 1.
Stall prevention during acceleration prevents the stalling and stopping of motors when the drive detects oC
[Overcurrent], oL2 [Drive Overloaded], or oL1 [Motor Overload] when you apply a large load during
acceleration or when you set sudden acceleration times related to load inertia.
0 : Disable
The Stall Prevention function does not operate during acceleration, and acceleration occurs for the set acceleration
time. If the acceleration time is too short, the motor does not fully accelerate during the set time, which causes the
drive to detect oL1 or oL2 and the motor to stop.
1 : Enabled
Enables the Stall Prevention During Acceleration function. Operation is different for different control methods.
• V/f Control, Open Loop Vector Control, or EZ Open Loop Vector Control
When the output current is more than the value set in L3-02 [Stall Prevent Level during Accel], the drive stops
acceleration. The drive stops deceleration when the output current is less than L3-02 - 15%. The Stall
Prevention function level automatically decreases for constant output ranges.
YASKAWA SIEPC71061705H GA700 Series Technical Manual
V/f CL-V/f OLV CLV AOLV
Sets the method of the Stall Prevention During Acceleration.
12.9 L: Protection Functions
Description
OLV/PM AOLV/PM CLV/PM EZOLV OLV/PM
Default
(Range)
1
(0 - 3)
12
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