Danfoss VLT AutomationDrive FC 301 Programming Manual page 507

Programming Guide | VLT® AutomationDrive FC 301/FC 302
Option Name
[5] Kinetic back-up, trip
© 2024.09
Description
A B C
U [V]
DC
U DC
SP-11*1.35
n [RPM]
Ref
Figure 84: Kinetic Back-up
A Normal operation
C Kinetic back-up
E Normal operation:
Ramping
The DC level during [4] Kinetic backup equals parameter 14-11
Mains Fault Voltage Level x 1.35. If the mains does not return, U
is maintained as long as possible by ramping the speed down
towards 0 RPM. Finally, the drive coasts. If the mains returns
while in kinetic back-up mode, U
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 Voltage Level x 1.35 x
DC
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 fulfill the criterion in point 1, and the drive tries to
reduce U to parameter 14-11 Mains Fault Voltage Level x
DC
1.35 by increasing the speed. This cannot be done as the mains
cannot be lowered.
• If the motor runs 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
mechanically 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.
AU275636650261en-003201 / 130R0334 |
Parameter Descriptions
D E A
t [S]
t [S]
B Mains failure
D Mains return
increases above parameter
DC
DC
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