
4-112
Stall prevention during run (08-00=x0xxb)
Stall prevention during run can only be used in V/F and SLV control mode.
This function prevents the motor from stalling by automatically reducing the output frequency during run.
If the AC Drive output current rises above the level set in parameter 08-03 for the time specified in parameter 08-22,
the AC Drive output frequency is automatically decreased following deceleration time 1 (00-15) or deceleration time 2
(00-17).
When the AC Drive output current falls
below the level set in parameter (08-03)
minus 2%, normal operation continues
and the output frequency increases to the
frequency reference using the
acceleration time 1 or acceleration time 2.
Refer to the figure at right.
08-22 (detection time)
Output
Frequency
T
dec1
(00-15)
T
dec2
(00-17)
t
2%
(Hysteresis)
08-03
Inverter
Output Current
Load
t
t
Stall prevention during deceleration (08-00=xx0xb)
Stall prevention during deceleration automatically increases the deceleration time based on the DC-bus voltage to
prevent over-voltage during deceleration. Refer to figure below for stall prevention during deceleration
When the DC-bus voltage exceeds the stall prevention level, deceleration will stop and the AC Drive will wait for the
DC-bus voltage to fall below the stall prevention level before continuing deceleration.
Stall prevention level can be set by 08-02, see table below
AC Drive model
08-02 default value
240V class
385VDC
480V class
770VDC
Stall prevention during deceleration function (08-00 to xx1xb) must be set to disabled when using a braking resistor
or braking module.
t
Output
frequency
Deceleration time is extended to
prevent overvoltage.
Deceleration
time