
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
.
Option:
Function:
130BC918.10
U
14-11*1.35
Ref
n [RPM]
t [S]
A B C D E
A
DC
U
DC
[V]
t [S]
A Normal operation
B Mains failure
C Kinetic back-up
D Mains return
E Normal operation: ramping
Illustration 3.58 Kinetic Back-up
The DC level during
[4] Kinetic back-up
equals
parameter 14-11 Mains Fault Voltage Level
x 1.35.
If the mains does not return, U
DC
is maintained
as long as possible by ramping the speed down
towards 0 RPM. Finally, the frequency converter
coasts.
If the mains returns while in kinetic back-up
mode, U
DC
increases above
parameter 14-11 Mains Fault Voltage Level
x 1.35.
This is detected in 1 of the following ways.
•
If U
DC
>
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
DC
to
parameter 14-11 Mains Fault Voltage
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.
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
Option:
Function:
[5]
Kinetic
back-up,
trip
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.
14-11*1.35
Ref
790 V
0
A
B
C
D
130BC920.10
U
n [RPM]
t [S]
DC
UDC
[V]
t [S]
A Normal operation
B Mains failure
C Kinetic back-up
D Trip
Illustration 3.59 Kinetic Back-up Trip
[6]
Alarm
[7]
Kin. back-
up, trip w
recovery
This option is valid in VVC
+
only. Kinetic back-up
with recovery combines the features of kinetic
back-up and kinetic back-up with trip. This
feature makes it possible to select between
kinetic back-up and kinetic back-up with trip,
based on a recovery speed, configurable in
parameter 14-15 Kin. Back-up 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. Back-up Trip
, normal operation is resumed. This
is equal to
[4] Kinetic Back-up
. The DC level
during
[7] Kin. back-up, trip w recovery
is
parameter 14-11 Mains Fault Voltage Level
x 1.35.
Parameter Descriptions
VLT
®
AutomationDrive FC 301/302
192
Danfoss A/S © 10/2018 All rights reserved.
MG33MP02
3
3
Содержание VLT AutomationDrive FC 302
Страница 2: ......