Drive Input Voltage
Stall Prevention Level during Deceleration
400 V Class
E1-01 ≥ 400 V
Vdc = 760 V
E1-01 < 400 V
Vdc = 660 V
Note: 1.
This setting should not be used in combination with a Dynamic Braking Resistor or other 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 braking option.
Figure 5.82
illustrates the function of Stall Prevention during deceleration.
Output Frequency
Deceleration characteristics
when Stall Prevention was
triggered during deceleration
Time
specified deceleration time
Figure 5.82 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 can not 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 Braking
Enables overexcitation deceleration. Overexcitation Braking (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.
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.
Name
Setting Range
Default
L3-05
Stall Prevention Selection During Run
0 to 2
1
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.
Setting 0: Disabled
Drive runs at the set frequency reference. A heavy load may cause the motor to stall and trip the drive with an oC or oL
fault.
5.8 L: Protection Functions
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SIEP C710606 20 OYMC AC Drive - V1000 User Manual
7/16/2008-13:23