YASKAWA V1000 Series Technical Manual page 193

Setting
2 Intelligent
3 Stall Prevention with Braking Resistor
4 Overexciation Deceleration
*Default Setting
Note: Settings 3 and 4 are not available when using a PM motor.
• L3-04 = 1
This setting enables Stall Prevention during deceleration.
Briefly stops deceleration and maintains the output frequency when the DC bus voltage exceeds the Stall Prevention level listed on the previous page.
Begins decelerating again at the specified deceleration time once the voltage in the DC bus drops below the Stall Prevention level. Stall Prevention may
be triggered repeatedly to avoid an overvoltage fault, and is useful when attempting to decelerate a load at a rate beyond what the drive is capable of.
400 V class
Note: Set L3-04 to "0" or "3" when using a Dynamic Braking Resistor or some other braking option. If Stall Prevention during deceleration is enabled, it will be triggered before
the braking resistor option can operate.
• The figure below illustrates how Stall Prevention works during deceleration.
Note: When Stall Prevention is activated during deceleration, it might take slightly longer to decelerate than the specified deceleration time. As this may not be appropriate in
conveyors or other such applications where positioning is a concern, you may want to consider using a braking resistor option instead.
• L3-04 = 2
Drive automatically adjusts Stall Prevention levels for optimum performance.
It suppresses the DC bus voltage, preventing the motor from stalling during deceleration while still maintaining the desired voltage levels specified in
L3-17. Here, the deceleration time is disregarded. When the frequency is relatively high, the drive will decelerate the motor slowly, increasing the speed
only as the frequency level drops. This function is affected by other parameters that include the DC bus voltage adjustment gain (L3-20), the deceleration
rate calculations gain (L3-21), inertia calculations for the motor deceleration time (L3-24), and the load inertia ratio (L3-25).
Note: Refrain from using this function in conveyors and other applications in which the stopping position is a concern. Yaskawa recommends using a braking option instead.
• L3-04 = 3
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.
• L3-04 = 4
Enables Overexcitation Deceleration.
Overexcitation (increasing the motor flux) can shorten the deceleration time faster than disabling Stall Prevention during deceleration (L3-04 = 0).
Repetitive overexcitation, however, can result in motor overload (OL1). In such situations, either shorten the deceleration time setting or consider using
a braking resistor.
Note: Because the flux level that allows 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
n
L3-06: Stall Prevention Level during Run
n
Stall Prevention during run allows the drive to operate at a continuous speed with a constant frequency output. It prevents speed loss or overload (OL1)
that would otherwise occur due to an increase in the load.
No.
L3-05
L3-06
*The upper limit for this setting is determined by C6-01 and L8-38. This setting rarely needs to be changed.
Note: This function is not available in V/f Control. When used in Open Loop Vector for PG motors, it functions much the same as the torque limit.
Detailed Description
Settings for L3-05 appear in the table below:
Setting
0 Disabled: Drive runs a set frequency. A heavy load may cause a fault.
1 Decelerates at Decel Time 1 (C1-02)
YASKAWA ELECTRIC SIEP C710606 18A YASKAWA AC Drive – V1000 Technical Manual (Preliminary)
Drive Voltage
200 V class
E1-01 greater than or equal to 400 V
E1-01 < 400 V
Output Frequency
specified deceleration time
Name
Stall Prevention Selection during Run
Stall Prevention Level during Run
Description
Stall Prevention Level during Deceleration
VDC = 380 V
VDC = 760 V
VDC = 660 V
Deceleration characteristics
when Stall Prevention was
triggered during deceleration
Time
Setting Range
0 to 2
* Determined by C6-01 and L8-38.
30 to 150
Description
5.8 L: Protection Functions
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