5.8 L: Protection Functions
YASKAWA ELECTRIC SIEP C710606 44B YASKAWA AC Drive T1000V Technical Manual 193
Figure 5.71 illustrates the function of Stall Prevention during deceleration.
Figure 5.71
Figure 5.71 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.
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.
■ 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.
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 and L3-06.
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.
Setting 1: Decelerate Using C1-02
If the current exceeds the Stall Prevention level set in parameter L3-06, the drive decelerates at Decel Time 1 (C1-02).
Once the current level drops below the value of L3-06 minus 2% for 100 ms it accelerates back to the frequency
reference at the active acceleration time.
Setting 2: Decelerate Using C1-04
Same as setting 1 except the drive decelerates at decel time 2 (C1-04).
No. Name Setting Range Default
L3-05 Stall Prevention Selection during Run 0 to 2 1
Output Frequency
Deceleration characteristics
when Stall Prevention was
triggered during deceleration
Time
Specified deceleration time
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