3-42 Ramp 1 Ramp Down Time
Range: Function:
Application
dependent*
[Application dependant] Enter the ramp-down time, i.e. the deceleration time from the synchronous motor speed n
s
to 0
RPM. Choose a ramp-down time such that no over-voltage arises in the inverter due to regenerative
operation of the motor, and such that the generated current does not exceed the current limit set
in par. 4-18
Current Limit
. The value 0.00 corresponds to 0.01 s in speed mode. See ramp-up time
in par. 3-41
Ramp 1 Ramp up Time
.
Par
. 3 − 42 =
t
dec
s
x
n
s
RPM
ref
RPM
3-45 Ramp 1 S-ramp Ratio at Accel. Start
Range: Function:
50 %* [Application dependant] Enter the proportion of the total ramp-up time (par. 3-41
Ramp 1 Ramp up Time
) in which the
acceleration torque increases. The larger the percentage value, the greater the jerk compensation
achieved, and thus the lower the torque jerks occurring in the application.
3-46 Ramp 1 S-ramp Ratio at Accel. End
Range: Function:
50 %* [Application dependant] Enter the proportion of the total ramp-up time (par. 3-41
Ramp 1 Ramp up Time
) in which the
acceleration torque decreases. The larger the percentage value, the greater the jerk compensation
achieved, and thus the lower the torque jerks in the application.
3-47 Ramp 1 S-ramp Ratio at Decel. Start
Range: Function:
50 %* [Application dependant] Enter the proportion of the total ramp-down time (par. 3-42
Ramp 1 Ramp Down Time
) where the
deceleration torque increases. The larger the percentage value, the greater the jerk compensation
achieved, and thus the lower the torque jerks in the application.
3-48 Ramp 1 S-ramp Ratio at Decel. End
Range: Function:
50 %* [Application dependant] Enter the proportion of the total ramp-down time (par. 3-42
Ramp 1 Ramp Down Time
) where the
deceleration torque decreases. The larger the percentage value, the greater the jerk compensation
achieved, and thus the lower the torque jerks in the application.
3.5.5 3-5* Ramp 2
Choosing ramp parameters, see 3-4*.
3-50 Ramp 2 Type
Option: Function:
Select the ramp type, depending on requirements for acceleration/deceleration. A linear ramp will
give constant acceleration during ramping. An S-ramp will give non-linear acceleration, compen-
sating for jerk in the application.
[0] * Linear
[1] S-ramp Const Jerk Acceleration with lowest possible jerk
[2] S-ramp Const Time S-ramp based on the values set in par. 3-51
Ramp 2 Ramp up Time
and par. 3-52
Ramp 2 Ramp
down Time
NB!
If S-ramp [1] is selected and the reference during ramping is changed the ramp time may be prolonged in order to realize a jerk free
movement which may result in a longer start or stop time.
Additional adjustment of the S-ramp ratios or switching initiators may be necessary.
3 Parameter descriptions FC 300 Programming Guide
78
MG.33.M8.02 - VLT
®
is a registered Danfoss trademark
3
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