4-236
cam
clutch
FLYWHEEL
Motor
Inverter
f
out
f
motor
Gear
box
Motoring : f
out
> f
motor
Overhauling : f
out
< f
motor
Figure 4.4.90 Stamping Operation
Over-voltage prevention (OVP) function monitors the DC-bus voltage and adjusts the speed reference,
acceleration and deceleration rate, to prevent the inverter from tripping on an overvoltage.
When the speed reference is reduced, the motor will start to decelerate. When the inverter is operating at a fixed
output frequency and excessive regenerative energy back to the inverter is detected the inverter will accelerate
the motor in order to reduce the DC-bus voltage. Refer to figure 4.4.91.
11-33
11-34
11-35
DC bus
voltage
DC bus filter
12-20
DC bus
voltage
+
-
11-36
Gain
Frequency
Reference
Limit
OVP
accel /
decel
time
11-37
Frequency
Reference
Fout
SFS
+
+
11-40= 0
11-40 = 1 or 2
Output
Frequency
Output Frequency
After SFS
OVP 2
accel /
decel
time
11-37
11-40 = 1
11-40 = 2
11-28
OVP2
Gain
Figure 4.4.91 OVP operation
