Danfoss FC 300 Series, Programming Manual

Page: 142 / 216

3.15.2 14-1* Mains On/Off
Parameters for configuring line failure monitoring and
handling. If a line failure appears, the adjustable frequency
drive will try to continue in a controlled manner until the
power in the DC link has been exhausted.
14-10 Line Failure
Option: Function:
14-10 Line Failure is typically used where very
short line power interruptions (voltage dips) are
present. At 100% load and a short voltage
interruption, the DC voltage on the main
capacitors drops quickly. For larger drives, it only
takes a few milliseconds before the DC level is
down to about 373 V DC and the main IGBT cuts
off and loses control over the motor. When line
power is restored, and the IGBT starts again, the
output frequency and voltage vector do not
correspond to the speed/frequency of the motor,
and the result is normally an overvoltage or
overcurrent, mostly resulting in a trip lock.
14-10 Line Failure can be programmed to avoid
this situation.
Select the function to which the adjustable
frequency drive must act when the threshold in
14-11 Mains Voltage at Mains Fault has been
reached.
14-10 Line Failure cannot be changed while motor
is running.
Controlled ramp-down:
The adjustable frequency drive will perform a
controlled ramp-down. If 2-10 Brake Function is
Off [0] or AC brake [2], the ramp will follow the
Overvoltage Ramping. If 2-10 Brake Function is [1]
Resistor Brake, the ramp will follow the setting in
3-81 Quick Stop Ramp Time .
Controlled ramp-down [1]:
After power-up, the adjustable frequency drive is
ready for start. Controlled ramp-down and trip [2]:
After power-up, the adjustable frequency drive
needs a reset for starting.
14-10 Line Failure
Option: Function:
1. The power is back before the energy
from DC / moment of inertia from load
is too low. The adjustable frequency
drive will perform a controlled ramp-
down when 14-11 Mains Voltage at
Mains Fault level has been reached.
2. The adjustable frequency drive will
perform a controlled ramp-down as
long as energy in the DC link is present.
After this point, the motor will be
coasted.
Kinetic backup:
The adjustable frequency drive will perform a
kinetic backup. If 2-10 Brake Function is Off [0] or
AC brake [2], the ramp will follow the Overvoltage
Ramping. If 2-10 Brake Function is [1] Resistor
Brake, the ramp will follow the setting in
3-81 Quick Stop Ramp Time .
Kinetic Backup [4]: The adjustable frequency drive
will keep on running as long as there is energy in
the system due to the moment of inertia
produced by the load.
Kinetic Backup [5]: The adjustable frequency drive
will ride through on speed as long as the energy
is present from moment of inertia from the load.
If the DC voltage goes below 14-11 Mains Voltage
at Mains Fault , the adjustable frequency drive will
perform a trip.
Parameter Descriptions FC 300 Programming Guide
3-120 MG.33.MA.22 - VLT
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