Megmeet MV300 Series - Page 210

210
P97.07 = 1 means the over-voltage stall action is enabled.
During the deceleration operation of the drive, due to the load inertia, the actual dropping rate of the
motor rotating speed may be lower than the dropping rate of the output frequency. At this time the
motor will feed back the power supply to the drive, causing the DC bus voltage of the drive to increase. If
no protection measure is taken for this, the drive will trip because of over-voltage.
The over-voltage stall protection function can detect the bus voltage during the drive deceleration
operation and compare it with the stall over-voltage point defined by P97.08 (relative to the standard bus
voltage). If it exceeds the stall over-voltage point, the drive output frequency will stop falling. The
deceleration operation will not be resumed until the bus voltage is detected to be lower than the stall
over-voltage point again, as shown in Fig.6-79.
Fig. 6-79 Over-voltage stall function
The auto current limiting function refers to automatically limiting the load current to lower than the preset
auto current limiting level (P97.10) through real time monitoring on the load current, so as to prevent the
tripping caused by current overshoot. This function is especially useful for the loads with large inertia or
drastic change.
The auto current limiting level (P97.10) defines the current threshold for the auto current limiting action.
Its setting range is the percentage relative to the drive rated current. Its leave- factory value varies
depending on the model, the G-type is 150% and the P-type is 110%.
The frequency reduction rate upon current limiting (P97.11) defines the adjustment rate of the output
frequency upon the auto current limiting.
If the frequency reduction rate upon current limiting (P97.11) is too small, it is difficult to get out of the auto
current limiting state, and it may ultimately cause overload fault. If its reduction rate is too large, the
frequency adjustment will be drastic, and the drive may be always in the power generation
state, which will cause over-voltage protection.
Fre
q
uenc
y
reduction rate u
p
on current limitin
g
0.00~99.99Hz/s
(
10.00
)
P97.11
Auto current limitin
g
level 20.0~200.0%
(
150.0%/110.0%
)
P97.10
Auto current limitin
g
action selectio
n
0~1
(
1
)
P97.09