YASKAWA CIMR-VU BA0001 Technical Manual page 224

5.8 L: Protection Functions
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 braking option.
Figure 5.84 illustrates the function of Stall Prevention during deceleration.
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
Refer to these parameter descriptions for details.
Note: As the deceleration time is not constant, Intelligent Stall Prevention should not be used in applications where stopping accuracy is a concern.
Use braking options instead.
Setting 3: Stall Prevention with Braking Option
Enables the Stall Prevention function while using a braking resistor. Use this setting if overvoltage occurs with L3-04 disabled
when using a braking resistor. This makes it possible to reduce the deceleration time.
Setting 4: Overexcitation Deceleration
Enables overexcitation deceleration. Overexcitation Deceleration (increasing the motor flux) shortens the deceleration time
compared to deceleration with no Stall Prevention (L3-04 = 0). Repetitive or long overexcitation deceleration can result in
motor overheat. In such situations, either shorten the deceleration time setting or use a braking resistor option.
Use parameters n3-13 and n3-23 for fine-tuning this function.
Note: Because the allowable flux level for overexcitation varies based on the flux saturation characteristics of the motor, set the proper
overexcitation level by adjusting the excitation gain in parameter n3-13. Motor characteristics and inertia of the machine influence the
deceleration time during overexcitation deceleration.
Setting 7: Overexcitation Deceleration 3
Provides faster deceleration than normal Overexcitation Deceleration (L3-04 = 4) by increasing the amount of overexcitation
current applied to the motor.
Note: When operation permits, use normal Overexcitation Deceleration (L3-04 = 4).
n L3-05: Stall Prevention Selection During Run
Stall Prevention During Run can prevent a motor from stalling by automatically reducing the speed when a transient overload
occurs while the motor is running at constant speed.
This parameter selects the Stall Prevention During Run method.
No.
L3-05
Note: 1. This function is not available in Open Loop Vector Control. Use the torque limit function instead.
2. When output frequency is 6 Hz or less, Stall Prevention During Run is disabled regardless of the setting in L3-05/06.
224
Output Frequency
specified deceleration time
Figure 5.84 Stall Prevention During Deceleration
Name
Stall Prevention Selection During Run
Deceleration characteristics
when Stall Prevention was
triggered during deceleration
YASKAWA ELECTRIC SIEP C710606 18F YASKAWA AC Drive – V1000 Technical Manual
Time
Setting Range
0 to 2
Default
1