Danfoss VLT AutomationDrive FC 301 Programming Manual page 161

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.
Option: 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 Voltage at Mains
Faultx1.35. This is detected in 1 of the following
ways.
•
If U
DC
at Mains Faultx1.35x1.05.
•
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 Voltage at Mains
Faultx1.35x1.02. This does not fulfil the
criterion in point 1, and the frequency
converter tries to reduce U
parameter 14-11 Mains Voltage at Mains
Faultx1.35 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.
[5] Kinetic The difference between kinetic back-up with and
back-up, without trip is that the latter always ramps down
trip 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.
MG33ML02
Programming Guide
> parameter 14-11 Mains Voltage
to
DC
Danfoss A/S © 02/2016 All rights reserved.
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: Function:
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 3.57 Kinetic Back-up Trip
[6] Alarm
[7] Kin. back- Kinetic back-up with recovery combines the
up, trip w features of kinetic back-up and kinetic back-up
recovery with trip. This feature makes it possible to select
between kinetic back-up and kinetic back-up
with trip, based on a recovery speed, config-
urable in parameter 14-15 Kin. Backup Trip
Recovery Level. If mains does not return, the
frequency converter ramps down to 0 RPM and
trips. If mains returns while in kinetic back-up at
a speed above the value in parameter 14-15 Kin.
Backup Trip Recovery Level, normal operation is
resumed. This is equal to [4] Kinetic Back-up. The
DC level during [7] Kinetic back-up is
parameter 14-11 Mains Voltage at Mains
Faultx1.35.
A B C D
t [S]
t [S]
159
3 3