Chapter 5 Function parameter
98
Ch
ap
ter 5
Deceleration
1
Deceleration and stop
2
F8.27
Frequency switching points for
momentary power cut deceleration
50.0%~100.0%
90%
☆
F8.28
Recovery voltage judgment time of
momentary power cut
0.00s~100.00s
0.50s
☆
F8.29
Judgment voltage of momentary power
cut
50.0%~100.0%(standard bus
voltage)
80.0%
☆
Bus voltage
Time(t)
Deceleration
time 3
Voltage protection of
momentary power out F8.27
Running frequency
Recovery acceleration time
F8.26=1
Deceleration
Judgment voltage of
momentary power cut action
F8.29
Recovery voltage judgment time F8.28
Voltage protection of
momentary power outF8.27
Running frequency
（F8.26=2:Deceleration）
Time(t)
Time(t)
Deceleration time 4
Deceleration
time 3
Deceleration
time 4
Diagram 5-28:
Schematic diagram of momentary power cut action
This feature means that when the momentary power cut happens or the voltage suddenly
reduces, the drive will reduce the output speed to compensate the reduced value of the inverter DC
bus voltage by using load feedback energy, in order to maintain the inverter to continue running.
If F8.26 = 1, when the momentary power cut happens or the voltage suddenly reduces, the
inverter will decelerate, when the bus voltage is back to normal, the inverter will normally
accelerate to the set frequency to run. To determine whether the bus voltage returns to normal or
not, check whether the bus voltage is normal and lasts for longer than the set time by F8.28.
If F8.26 = 2, when the momentary power cut happens or the voltage suddenly reduces, the
inverter will decelerate till to stop.
F8.30 Load drop protection selection
Invalid
0
0
☆
Valid
1
F8.31 Load drop detection level
0.0%~100.0% (Rated current)
10.0%
☆
F8.32 Load drop detection time
0.0s~60.0s
1.0s
☆
If the load drop protection function is active, when the inverter output current is less than the
load drop detection level (F8.31)and the duration is longer than the load drop detection
time(F8.32), the inverter output frequency is automatically reduced to 7% of the rated frequency.
During the load drop protection, if the load recovers, the inverter automatically resumes to the set
frequency to run.
