Danfoss VLT AutomationDrive FC 301 Programming Manual page 170

Parameter Descriptions
14-10 Mains Failure
Options [1] Ctrl. ramp-down, [2] Ctrl. ramp-down, trip, [5] Kinetic
back-up, trip, [7] Kin. back-up, trip w recovery are not active when
the option [2] Torque is selected in parameter 1-00 Configuration
Mode.
3 3
Option:
[5] Kinetic
back-up,
trip
168
VLT
Function:
towards 0 RPM. Finally, the frequency converter
coasts.
If the mains returns while in kinetic back-up
mode, U increases above
DC
parameter 14-11 Mains Fault Voltage Level x 1.35.
This is detected in 1 of the following ways.
•
If U > parameter 14-11 Mains Fault
DC
Voltage Level x 1.35 x 1.05.
•
If the speed is above the reference. This
is relevant if the mains comes back at a
lower level than before, for example
parameter 14-11 Mains Fault Voltage
Level x 1.35 x 1.02. This does not fulfil
the criterion in point 1, and the
frequency converter tries to reduce U
to parameter 14-11 Mains Fault Voltage
Level x 1.35 by increasing the speed.
This cannot be done as the mains
cannot be lowered.
•
If running mechanically. The same
mechanism as in point 2 applies, but
the inertia prevents the speed from
going above the reference speed. This
leads to the motor running mechan-
ically until the speed is above the
reference speed and the situation in
point 2 occurs. Instead of waiting for
that criterion, point 3 is introduced.
The difference between kinetic back-up with and
without trip is that the latter always ramps down
to 0 RPM and trips, regardless of whether mains
returns or not.
The function does not detect if mains returns.
This is the reason for the relatively high level on
the DC link during ramp down.
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®
AutomationDrive FC 301/302
14-10 Mains Failure
Options [1] Ctrl. ramp-down, [2] Ctrl. ramp-down, trip, [5] Kinetic
back-up, trip, [7] Kin. back-up, trip w recovery are not active when
the option [2] Torque is selected in parameter 1-00 Configuration
Mode.
Option:
DC
[6] Alarm
14-11 Mains Fault Voltage Level
Range:
Size
related - 600
*
V]
Function:
A B C
U [V]
DC
790 V
U DC
14-11*1.35
n [RPM]
Ref
0
A Normal operation
B Mains failure
C Kinetic back-up
D Trip
Illustration 3.62 Kinetic Back-up Trip
Function:
[180 This parameter defines the threshold voltage
at which the function in
parameter 14-10 Mains Failure is activated.
Select the detection level depending on the
supply quality. For a supply of 380 V, set
parameter 14-11 Mains Fault Voltage Level to
342 V. This results in a DC detection level of
462 V (parameter 14-11 Mains Fault Voltage
Levelx1.35).
NOTICE
Converting from VLT 5000 to FC 300:
Even though the setting of the mains
voltage at mains fault is the same for
VLT 5000 and FC 300, the detection
level is different. Use the following
formula to obtain the same detection
level as in VLT 5000:
Parameter 14-11 Mains Fault Voltage
Level (VLT 5000 level) = value used in
VLT 5000 x1.35/sqrt(2).
D
t [S]
t [S]
MG33MO02