Danfoss VLT AutomationDrive FC 300 Programming Manual page 140

Parameter Descriptions
3.15.2 14-1* Mains On/Off
Parameters for configuring mains failure monitoring and
handling. If a mains failure appears, the frequency converter
will try to continue in a controlled way until the power in the
DC link has been exhausted.
14-10 Mains Failure
Option: Function:
14-10 Mains Failure is typically used where very
short mains 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 373V DC and the main IGBT cuts
off and looses the control over the motor. When
the mains is restored, and the IGBT starts again,
the output frequency and voltage vector does
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 Mains Failure can be programmed to avoid
this situation.
Select the function to which the frequency
converter must act when the threshold in
14-11 Mains Voltage at Mains Fault has been
reached.
14-10 Mains Failure cannot be changed while
motor is running.
Controlled ramp down:
The frequency converter will perform a controlled
ramp down. If 2-10 Brake Function is Off [0] or AC
brake [2], the ramp will follow the Over Voltage
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 frequency converter is ready
for start. Controlled ramp down and trip [2]: After
power-up the frequency converter needs a reset
for starting.
DC Voltage
Output Speed rpm
Par 14-11
Mains
DC Voltage
Output Speed rpm
Par 14-11
Mains
FC 300 Programming Guide
Over Voltage Control Level
Time
Over Voltage Control Level
Time
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14-10 Mains Failure
Option: Function:
1. The power is back before the energy
from DC /moment of inertia from load is
too low. The frequency converter will
perform a controlled ramp down when
14-11 Mains Voltage at Mains Fault level
has been reached.
2. The frequency converter 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 back-up:
The frequency converter will perform a Kinetic
back-up. If 2-10 Brake Function is Off [0] or AC
brake [2] , the ramp will follow the Over Voltage
Ramping. If 2-10 Brake Function is [1] Resistor
Brake the ramp will follow the setting in
3-81 Quick Stop Ramp Time.
Kinetic Back-up [4]: The frequency converter will
keep on running as long as there is energy in the
system due to the moment of inertia produced by
the load.
Kinetic Back-up [5]: The frequency converter 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 frequency converter will perform
a trip.
DC Voltage
Output Speed rpm
Par 14-11
Mains
DC Voltage
Output Speed rpm
Par 14-11
Mains
NOTE
For the best Kinetic Backup performance the
advanced motor data parameters,
1-30 Stator Resistance (Rs) to 1-35 Main
Reactance (Xh), must be accurate.
[0] No This selection does not present a danger to the
function frequency converter, but a trip lock would
*
normally be the result of the short voltage
interruptions.
[1] Ctrl. ramp- This selection will keep the output frequency
down following the motor speed. The IGBT will not
Over Voltage Control Level
Time
Over Voltage Control Level
Time
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