KEB COMBIVERT F5-A Applications Manual page 410

Protective functions
Behaviour at power recovery and below the restart value (Pn.48)
The following parameters effect the behaviour of the inverter if the mains voltage returns during the power-off
function.
Restart value (Pn.48)
Depending on the application, it can be reasonable to execute the restart on power recovery only above a de-
fined output value. This restart value is adjusted in Pn.48.
Dependent on the setpoint value source (Pn.44 bit 6 ..7) following conditions occur:
1. Control to the starting voltage (Pn.44 Bit 6...7 = 0):
A restart is carried out at power recover if the output value is higher than the restart value. The output value is
kept constant during the restart delay (Pn.52). Afterwards it is accelerated to the current setpoint value. Below
the restart value it is delayed at power recovery with the fast-stop function (DEC ramp at F5-B/C). If the power
does not recover, the controller parameters of the active current controller are decreased linearly with the base
value in v/f-characteristic operation.
2. Control to voltage setpoint Pn.50 for a base value smaller than the restart value (Pn.44 bit 6...7 = 2):
As long as the base value is greater than the restart value, the inverter behaves as in item 1.Below the restart
value the voltage setpoint value of Pn.50 is increased and with active current control (without speed detection)
the control parameters of the active current control are reduced linearly with the output value. At power recove-
ry a restart is only possible after reaching the standstill.
3. Control to voltage setpoint Pn.50 or braking torque Pn.47 (Pn.44 bit 6.,.7 = 1 or 3):
The controller parameters of the active current controller (without speed detection) are reduced below the re-
start value linearly with the output value.
At power recovery a restart is only possible after reaching the standstill.
Power Off: max. time for restart at power recovery (Pn.96)
Value range: 0 (off – 100.00 s
Default value : 0(off)
not set-programmable
This parameter has principally the same function as Pn.48 (power off restart threshold).
The drive does not restart at system recovery if the adjusted time is up but it is decelerated with quick stop to
standstill.
If both parameters are adjusted (Pn.48 and Pn.96) the condition that is reached earlier is valid.
Example: Pn.48 = 25 Hz; Pn.96 = 10 s.
a) 25 Hz fall below after 8 s - no restart after 8 s
a) 25 Hz fall below after 12 s - no restart after 10 s
Pay attention:
The maximum time contains Pn.52 (restart delay).
Example: Pn.52 = 1 s; Pn.96 = 10 s.
a)System recovery after 8.5 s - restart after 9.5 s
b) System recovery after 9.5 s - no restart because Pn.96 is exceeded.
Behaviour on reaching standstill (Pn.44 Bit 3.,.4)
Pn.44 bit 3..4 determines how the drive behaves on reaching standstill.
Pn.44 bit 3...4 = 0:
The inverter modulates independent of a rotation setting with the adjusted boost and is in status "78: power off
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