5.8 L: Protection Functions
218
YASKAWA ELECTRIC SIEP C710616 30B YASKAWA AC Drive T1000A Technical Manual
Note: 1.
When setting L2-05 below the default value, an AC reactor option should be installed to the input side of the power supply to prevent
damage to drive circuitry.
2.
This parameter has no effect on triggering the KEB function, even when S4-01 is set > 0. Use S4-03 to set KEB Start Voltage Level.
u
L3: Stall Prevention
When the load is too high or acceleration and deceleration times are too short, the motor may be unable to keep up with
the frequency reference, resulting in excessive slip. During acceleration, this usually causes an overcurrent fault (oC),
drive overload (oL2), or motor overload (oL1). During deceleration, it can cause excessive regenerative power to flow
back into the DC bus capacitors, eventually causing the drive to fault out from overvoltage (oV). The drive can prevent
the motor from stalling and still reach the desired speed without the user needing 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.
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, thus tripping 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:
The drive stops accelerating if the output current exceeds the Stall Prevention level set in L3-02. Acceleration will
resume again once the output current falls 15% below the level set in L3-02.
Figure 5.81
Figure 5.81 Stall Prevention During Acceleration for Induction Motors
• Open Loop Vector Control for PM:
Acceleration is stopped when the output current reaches the level set in parameter L3-02. Once the time set in
parameter L3-27 passes, the drive decelerates using the deceleration time set in L3-22 (
Time at Stall Prevention during Acceleration on page 219
). Once the output current falls 5% below the level set in
L3-02, the drive stop decelerating and starts to accelerate again.
<2> The default setting for 400 V class drives will vary depending on if the drive input voltage is over or under 400 V.
No.
<1> Setting 2 is not available for PM OLV.
Name
Setting Range
Default
L3-01
Stall Prevention Selection during Acceleration
0 to 2
1
Stall Prevention Level
During Acceleration
L3-02
15% of
L3-02
Output current
Output frequency
Time
Time
Controls the output frequency
to prevent the motor from stalling
