YASKAWA A1000 Technical Manual page 113

n L3-04: Stall Prevention Selection during Deceleration
Stall Prevention during deceleration controls the deceleration based on the DC bus voltage and prevents an overvoltage fault
caused by high inertia or rapid deceleration.
No.
L3-04 Stall Prevention Selection During Deceleration
<1> Settings 3 through 5 are not available in OLV/PM. Settings 2 through 5 are not available in AOLV/PM and CLV/PM.
<2> Setting 3 is not available for models CIMR-Ao4A0930 and 4A1200.
Setting 0: Disabled
The drive decelerates according to the set deceleration time. With high inertia loads or rapid deceleration, an overvoltage fault
may occur. If an overvoltage fault occurs, use dynamic braking options or switch to another L3-04 selection.
Setting 1: General-purpose Stall Prevention
The drive tries to decelerate within the set deceleration time. The drive pauses deceleration when the DC bus voltage exceeds
the Stall Prevention level and then continues deceleration when the DC bus voltage drops below that level. Stall Prevention
may be triggered repeatedly to avoid an overvoltage fault. The DC bus voltage level for Stall Prevention depends on the input
voltage setting E1-01.
Drive Input Voltage
200 V Class
400 V Class
600 V Class
Note: 1. Do not use this setting in combination with a Dynamic Braking Resistor or other dynamic braking options. If Stall Prevention during
deceleration is enabled, it will be triggered before the braking resistor option can operate.
2. This method may lengthen the total deceleration time compared to the set value. If this is not appropriate for the application consider using
a dynamic braking option.
Figure 4.33 illustrates the function of Stall Prevention during deceleration.
Setting 2: Intelligent Stall Prevention
The drive adjusts the deceleration rate so the DC bus voltage is kept at the level set to parameter L3-17. This produces the
shortest possible deceleration time while protecting the motor from stalling. The selected deceleration time is disregarded and
the achievable deceleration time cannot be smaller than 1/10 of the set deceleration time.
This function uses the following parameters for adjusting the deceleration rate:
• DC bus voltage gain (L3-20)
• Deceleration rate calculations gain (L3-21)
• Inertia calculations for motor acceleration time (L3-24)
• Load inertia ratio (L3-25)
Note: The deceleration time is not constant. Do not use Intelligent Stall Prevention in applications where stopping accuracy is a concern. Use dynamic
braking options instead.
Setting 3: Stall Prevention with dynamic braking option
Enables the Stall Prevention function while using a dynamic braking resistor. Overvoltage problems in the DC bus can occur
if Stall Prevention during deceleration is disabled (L3-04) in OLV and a dynamic braking option is installed. Set L3-04 to 3
to remedy this situation.
YASKAWA ELECTRIC TOEP C710616 41B YASKAWA AC Drive - A1000 Quick Start Guide
Name
Stall Prevention Level during Deceleration
Output Frequency
specified deceleration time
Figure 4.33 Stall Prevention During Deceleration
4.6 Basic Drive Setup Adjustments
Setting Range
<1> <2>
0 to 5
377 Vdc
754 Vdc
1084 Vdc
Deceleration characteristics
when Stall Prevention was
triggered during deceleration
Time
Default
1
4
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