Normal operation: Ramping
If mains returns while in kinetic back-up at a speed below parameter 14-15 Kin. Back-up Trip Recovery Level, the
drive ramps down to 0 RPM using the ramp and then trips. If the ramp is slower than the system ramping down
on its own, the ramping is done mechanically and U
DC
is at the normal level (U
DC,m
x 1.35).
SP-11*1.35
Ref
U
DC
A B C D E F
e30bc923.10
0
U
DC
[V]
n [RPM]
t [S]
t [S]
Illustration 86: Kinetic Back-up Trip w/Recovery, Slow Ramp, Mains Returns Below Parameter 14-15 Kin. Back-up Trip Recov-
ery Level
Kinetic back-up, ramping to trip
If the ramp is quicker than the ramp-down speed of the application, the ramping generates current. This results
in a higher U
DC
, which is limited using the brake chopper/resistor brake.
14-11*1.35
U
DC
0
U
DC,b
Ref
A B C D E F
e30bc924.10
U
n [RPM]
t [S]
DC
[V]
t [S]
Illustration 87: Kinetic Back-up Trip w/Recovery, Quick Ramp, Mains Returns Below Parameter 14-15 Kin. Back-up Trip Recov-
ery Level
Kinetic back-up ramping to trip
The purpose of this function is to avoid mains failure trips (Alarm 36), for example, where mains is weak or can
be disturbed by other motors being started directly. When the drive detects mains failure, the drive ramps
down the motor using kinetic back-up and coasts the drive. The drive remains coasted for the time set in pa-
rameter 40-14 Mains Loss Duration - the actual ramp-down time in KB. If mains returns after that time, the drive
ramps up again. When parameter 40-14 Mains Loss Duration = 60, the drive immediately restarts the ramp up if
the start command is still valid from PLC and mains voltage is back. When parameter 40-14 Mains Loss Duration
= <60, the drive waits for the timer in parameter 40-14 Mains Loss Duration to expire before restarting ramp up.
AU275636650261en-000101 / 130R0334456 | Danfoss A/S © 2022.12
Parameter Descriptions
VLT AutomationDrive FC 301/302
Programming Guide
To Next Page
Loading...
Need help?
General