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L3: Stall Prevention
The motor may experience excessive slip because it cannot keep up with the frequency reference when the load is too high or
acceleration and deceleration times are too short. If the motor slips during acceleration, it usually causes an overcurrent fault
(oC), drive overload (oL2), or motor overload (oL1). If the motor slips during deceleration, it can cause excessive regenerative
power to flow back into the DC bus capacitors, and eventually cause the drive to fault out from overvoltage (ov). The Stall
Prevention Function prevents the motor from stalling and while allowing the motor to reach the desired speed without requiring
the user to change the acceleration or deceleration time settings. The Stall Prevention function can be set separately for
acceleration, operating at constant speeds, and deceleration.
n
L3-01: Stall Prevention Selection during Acceleration
Stall Prevention during acceleration prevents tripping with overcurrent (oC), motor overload (oL1), or drive overload (oL2)
faults common when accelerating with heavy loads.
L3-01 determines the type of Stall prevention the drive should use during acceleration.
No.
Name
Setting Range
Default
L3-01
Stall Prevention Selection during Acceleration
0, 1, 3
1
<1> Setting 3 is not available for OLV/PM.
Setting 0: Disabled
No Stall Prevention is provided. If the acceleration time is too short, the drive may not be able to get the motor up to speed
fast enough, causing an overload fault.
Setting 1: Enabled
Enables Stall Prevention during acceleration. Operation varies depending on the control mode.
• V/f Control, V/f Control with PG, and Open Loop Vector Control:
Acceleration is reduced when the output current value exceeds 85% of the level set to parameter L3-02 for a longer than the
time set to L3-27. The acceleration stops when the current exceeds L3-02. Acceleration continues when the current falls
below L3-02 for longer than the time set to L3-27.
The Stall Prevention level is automatically reduced in the constant power range.
Refer to L3-03: Stall Prevention Limit
during Acceleration/Deceleration on page 317
.
Stall Prevention Level
During Acceleration
L3-02
L3-02
-15%
Output current
Output frequency
Time
Time
Controls the output frequency
to prevent the motor from stalling
Figure 5.91 Stall Prevention During Acceleration for Induction Motors
• Open Loop Vector Control for PM:
Acceleration stops when the output current reaches the level set to parameter L3-02. When the time set to parameter L3-27
passes, the drive decelerates using the deceleration time set to L3-22 (
Refer to L3-22: Deceleration Time at Stall Prevention
during Acceleration on page 319
). Deceleration stops when the current falls below 85% of L3-02,. The drive will attempt
to reaccelerate after the time set to L3-27.
5.8 L: Protection Functions
316
YASKAWA ELECTRIC SIEP C710636 04D U1000 Industrial MATRIX Drive Technical Manual
Summary of Contents for U1000 iQpump Drive
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