YASKAWA A1000 Series Technical Manual page 258

5.8 L: Protection Functions
L3-04: Stall Prevention Selection during Deceleration
■
Stall Prevention during deceleration can control the deceleration based on the DC bus voltage and prevent an overvoltage
fault caused by high inertia or rapid deceleration.
No.
L3-04
<1> Settings 3 through 5 are not available in OLV/PM. Settings 2 through 5 are not available in AOLV/PM and CLV/PM.
Setting 0: Disabled
When this setting is used, the drive decelerates according to the set deceleration time. With high inertia loads or rapid
deceleration, an overvoltage (ov) fault may occur. In this case use dynamic braking options or switch to another L3-04
selection.
Setting 1: General-purpose Stall Prevention
With this setting the drive tries to decelerate within the set deceleration time. When the DC bus voltage exceeds the Stall
Prevention level, the drive pauses deceleration. Deceleration continues as soon as 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
Note: 1. This setting should not be used 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 5.99 illustrates the function of Stall Prevention during deceleration.
Figure 5.99
Setting 2: Intelligent Stall Prevention
With this setting, the drive adjusts the deceleration rate so that the DC bus voltage is kept at the level set in parameter L3-
17. This way the shortest possible deceleration time is achieved while the motor is protected from stalling. The
deceleration time that has been selected is disregarded, but 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: As the deceleration time is not constant, Intelligent Stall Prevention should not be used 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.
258
Name
Stall Prevention Selection During Deceleration
200 V Class
400 V Class
Output Frequency
specified deceleration time
Figure 5.99 Stall Prevention During Deceleration
Stall Prevention Level during Deceleration
Deceleration characteristics
when Stall Prevention was
triggered during deceleration
YASKAWA ELECTRIC SIEP C710616 27C YASKAWA AC Drive A1000 Technical Manual
Setting Range
0 to 5
<1>
377 Vdc
754 Vdc
Time
Default
1